Forage-Animal Relationships under Grazing Conditions

FORAGE-ANIMAL RELATIONSHIPS UNDER GRAZING CONDITIONS

Sponsoring Institution

National Institute of Food and Agriculture

Project Status

COMPLETE

Funding Source

HATCH

Reporting Frequency

Annual

Accession No.

0082599

Grant No.

(N/A)

Cumulative Award Amt.

(N/A)

Proposal No.

(N/A)

Multistate No.

(N/A)

Project Start Date

Feb 18, 2009

Project End Date

Feb 17, 2014

Grant Year

(N/A)

Program Code

[(N/A)]- (N/A)

Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001

Performing Department
Overton-TAMU Agr Res Cntr

Non Technical Summary
The need for definitive, comparative information on forage sustainability, grazing systems, animal performance, and economic implications in Texas becomes evident when considering that forages supply approximately 70% of the nutrients consumed by the $7.1 billion Texas livestock industry. More than 90% of the feed supply in cow-calf operations and 60% in slaughter beef operation are derived from forages. Collectively, forages on pasture and rangeland occupy nearly 70% of the 130.5 million acres of land area in Texas. Much of this area includes land that is either marginally or completely unsuited for row crop production. Forages, therefore, are the primary crop in Texas that supports livestock, wildlife, and recreation as well as being an inseparable component of resource conservation and environment-sustainability. Forage-animal agriculture continues to function on a segmented production scheme that often has separate ownership and management options for the individual cow-calf, stocker, and feeder components. The unprecedented, rapid increases in energy-related costs of fuel, feed grains, fertilizers, and seeds during 2006 to 2008 created major changes in infrastructure and management strategies for pasture-animal production. These economic conditions enforced the need for enhanced efficiency from plant-food nutrients via nutrient recycling and increased efficiency of animal production. A 2008 survey questionnaire sent to 25 land grant university forage-animal researchers in the eastern half of the US ranked the top four research needs as: 1) pasture systems and efficiency of production; 2) interface with energy concerns; 3) forage cultivar evaluations and persistence; and 4) environmental impacts. Additional research needs ranked fifth was soil fertility and nutrient management, and ranked sixth out of eleven was animal performance and behavior. Forage germplasm and cultivars will be evaluated for productivity, persistence, and nutritive value in small plots and in pastures. Stocking strategies and fertility regimens will provide a quantified assessment of the impact of nutrient cycling on soil plant food nutrient accumulation forage stand maintenance, species diversity and invasion, and animal performance. Post-weaning stocking of Tifton 85 and Coastal bermudagrass during summer months and small grain plus ryegrass during winter months will provide a database for assessing performance, risks, and economic potential for management. Continued ownership during feedlot residence and resultant carcass attributes will enhance birth-to-harvest databases for use in modeling and decision aids for management operations who chose a component or a total system approach to forage-animal production. These data bases along with an array of production costs and animal prices will provide definitive stocking-management strategies for producers who may range from a novice to a multi-faceted integrated operator.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	1610	1060	20%
205	1620	1010	10%
205	1620	1020	10%
205	1621	1060	10%
205	1631	1020	10%
205	1644	1020	10%
307	3310	1010	20%
307	3320	1020	10%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 205 - Plant Management Systems; 307 - Animal Management Systems;

Subject Of Investigation
3320 - Meat, beef cattle; 3310 - Beef cattle, live animal; 1620 - Warm season perennial grasses; 1644 - Winter annual legumes; 1610 - Pasture; 1621 - Cool season perennial grasses; 1631 - Winter annual grasses;

Field Of Science
1060 - Biology (whole systems); 1010 - Nutrition and metabolism; 1020 - Physiology;

Keywords

Goals / Objectives
1. Evaluate forage germplasm and cultivars for dry matter production, nutritive value, persistence, and sustainability under various defoliation regimens. 2. Ascertain the impact of stocking rate and fertilization regimens on soil nutrient status, forage stand maintenance, biodiversity of forages, and nutrient cycling in bermudagrass pastures. 3. Quantify the effects of stocking strategies, stocking methods, and forage utilization systems on pasture and animal performance parameters from birth-to-harvest. 4. Describe biological efficiencies and project economic implications of production systems using forage-animal interface database.

Project Methods
OBJ 1: Germplasm and cultivars of bermudagrass, switchgrass, tall fescue, annual ryegrass, clovers, small grains, tall fescue, cowpeas, and lablab will be grown in replicated plot-sized areas and/or pasture units. Seasonal and total dry matter production and nutritive value will be assessed on forage defoliated at different regimens of height and frequency via clipping and/or grazing. Forage measurements include mass, vigor, stand maintenance, protein, fiber components, and digestibility. Principal procedures will include PROC GLM and PROC MIXED for the completely randomized and randomized complete block designs. OBJ 2: At each of three stocking rates for both Coastal and common bermudagrass, overseeding x fertility treatments will include: (a) ryegrass plus N fertilizer and (b) clover without N. Soil nutrient status (pH, N, P, K, etc) carbon, soil compaction, root-rhizome density, forage mass, stand maintenance and density, vigor, species diversity and composition, and animal performance per animal and per unit land area will be quantified. Nutritive value will include protein, fiber components, digestibility, etc. Each pasture will be blocked for taking soil samples to various depths, assessment of forage stand, and species diversity. Bermudagrass plants exhibiting differentiation in leaf and stem growth attributes in addition to seed coloration and formation will be sampled and analyzed for genetic diversity. This experiment will be analyzed via SAS using PROC MIXED. OBJ 3: At weaning, calves will be grazed on Tifton 85 and Coastal bermudagrass (fall calves), or small grain-ryegrass or tall fescue (winter calves). Pastures will be grazed at three or more stocking rates on a continuous and/or rotational stocking method. Forage parameters to be taken include mass, nutritive value, stubble height, and pasture utilization. Lifetime performance of animals and stocking strategies will be used for both segmented and life-time performance parameters. Statistical procedures of PROC GLM and PROC MIXED, will be used to assess potential relationships between previous forage treatment, feedlot performance, and carcass traits. Growth rate of calves will be assessed to detect the influence of previous treatment(s) on feedlot performance and carcass traits. OBJ 4: Data collected from the previously-listed objectives as well as data from previous years' research from selected long-term stocked pastures will have significant implications for management of sustained pasture-animal production. Use of these data will be used to develop mathematical expressions for decision aids, management grids, expert systems, and research initiatives. Cooperative relationships will include statisticians, agricultural economists, plant physiologists, animal nutritionists, and others who have expertise in the transformation of biological parameters into models for use by professionals and producers interested in sustained, economic production for forage-based livestock systems.

Progress 02/18/09 to 02/17/14

Outputs
Target Audience: The major target audiences served by this project are beef cow-calf producers forage and hay producers, stocker operators, soil-forage-animal scientists. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Presentations at professional society meetings. Presentations of research findings to stakeholders at state meetings. How have the results been disseminated to communities of interest? peer review journals, Texas A&M Research Reports What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Long-term stocking of bermudagrass pastures and fertility regimens on content and distribution of soil Phosphorus. Continued evaluation of additional soil nutrients under long-term stocking ofpastures. Quantify relationships between forage allowance and liveweight gains for young cattle atdifferent stocking rates on rye-ryegrass and Tifton 85 bermudagrass pastures. Evaluation of stocking rates and forage allowance on performance of F-1 Hereford x Brahmancows and Simmental-sired calves. Quantified birth-to-harvest attributes of calves on various stocked pastures during both pre- and post-weaning stages, and on to feedlot, and carcass trait data.

Publications

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: Maton rye and TAM-90 annual ryegrass were sod-seeded into bermudagrass pastures and stocked continuously (CONT) or rotationally (ROTN) each at three levels of forage mass. Stocking rates of weaned calves (550 lbs each) were used to quantify gain per animal (ADG) and gain per acre. Stocking rates of 2.0, 2.6, and 3.2 calves/acre, respectively, for low, medium, and high, were used to create forage mass differences. Pastures were stocked from late December to mid-May. The 8-paddock ROTN system consisted of a 2-day graze and 14-day deferment cycle. Forage mass and forage quality samples were taken at 14-day intervals throughout the stocking period of both CONT and ROTN. Results of this experiment were disseminated to agronomists and animal scientists through abstracts and poster presentation at professional society meetings. Production and economic implications of these stocking systems were delivered to stakeholders via regional and state-wide meetings, and via research technical reports. Dixie crimson clover and Iron-and-Clay cowpeas were planted into a cropping systems experiment to quantify effect on soil N and C, and on grain production from grain sorghum. Crimson was established as a green manure crop and cowpeas were planted as a companion crop to assess N-fixation and subsequent impact on soil attributes and crop production. Four fertilization rates of N were used to evaluate differences between organic and inorganic sources of N. Results from this experimentation were disseminated to professional soil and crop scientists at regional and national society meetings. Production and economic impact of legumes vs N-fertilization were disseminated. PARTICIPANTS: Dr. G.R. Smith was a collaborator on evaluation of legume and ryegrass for forage. Drs. R.D. Randel, L.O. Tedeschi and T.D.A. Forbes were collaborators in the animal nutrition and physiology components of this project. TARGET AUDIENCES: Research and extension scientists and stakeholders in the humid southeaster US are interested in sod-seeding bermudagrass pastures with small grain and ryegrass for stocker cattle. Specific interests include stocking rates and resultant gains per animal and per unit land area. Scientists and stakeholders are also interested in use of legumes as replacement for N fertilization in cropping systems. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Stocking rate was the most important management strategy affecting ADG and gain per acre. The ADG for low, medium, and high stocking rates, respectively, was 2.9, 2.2, and 1.1 lbs/day. There was no difference in ADG between CONT vs ROTN stocking systems. Gain per acre was about 1000 lbs/ac for both low and medium stocked pastures, and 400 lbs/ac for high stocked pastures. Forage mass of 1650 lbs/ac was optimum for maximum ADG; thus stocking rate can be increased based on forage mass to increase gain per acre. The optimum forage allowance of forage DM:animal body weight for maximum ADG was optimum at 1.0, or a 1:1 relationship. The forage mass to ADG relationships allow stakeholders to use appropriate stocking rates to optimize economic returns per unit land area. Pasture input costs and estimates of animal performance provides information for management strategies targeted at purchase price, margin, and sell prices for stocker operations. Use of crimson clover as a cover-crop and green manure crop contributed 100 lbs/ac N to the system when soil-incorporated. An interaction between the clover cover crop and 80 lbs/ac N fertilizer increased grain yield of Pioneer 84G62 to 2000 lbs/ac. The biomass yield of grain sorghum was not affected by clover planting. The companion crop, cowpeas, did not contribute N for grain or biomass production and the competitive aspect of cowpeas reduced grain yields by more than 70%. Thus, the competition for moisture and light exerted by cowpeas proved to dramatically reduce grain sorghum production. Hence, cowpeas should be used as a green manure crop in years proceeding grain sorghum and not be used as a potential N-fixing, companion plant. Management strategies using legume cover crops and green manure crops offer positive implications for stakeholders; whereas, the joint planting of cowpeas and grain sorghum is not a viable production alternative.

Publications

Aguiar, A.D., T.D.A. Forbes, F.M. Rouquette, Jr., L.O. Tedeschi and R.D. Randel. 2012. Evaluating the statistical variation n estimating forage dry matter intake of g razing Brahman bulls using n-alkanes. J. Agri. Sci. doi:10.1017/S0021859612000354.
Cleere, J.J., F.M. Rouquette, Jr., A.D. Herring, J.W. Holloway, H. Lippke, B.G. Warrington, C.R. Long, K.R. Pond, M.F. Miller, G.E. Aiken. 2012. Stocker growth on rye and ryegrass pastures affects subsequent feedlot gains and carcass traits. Online. Forage and Grazinglands doi:10.1094/FG-2002-0524-01-RS.
Husmoen, D., D.M. Vietor, F.M. Rouquette, Jr. and J.T. Cothren. 2012. Variation of responses to water stress between Tifton 85 and Tifway or Coastal bermudagrass. Crop Sci. 52:2385-2391.
Wiley, L.M., L.O. Tedeschi, T. D. A. Forbes, F.M. Rouquette, Jr., R.D. Randel, S.E. Dowd. 2012. A comparison of ruminal microbial populations of residual feed intake-indexed Brahman bulls under grazing conditions. American Society of Animal Science - Southern Section. February 6-8, Birmingham, AL. Abstract
Adams, K.K., L.R. Chenault, J. Valenta, R.N. Vaughn, A.K. Torres, K.J. Kochan, T.H. Welsh, R.D. Randel, F.M. Rouquette, A.D. Herring and P.K. Riggs. 2012. Expression profiling of testicular sense and antisense RNA transcripts of Brahman bulls. ADSA-ASAS Abst. M34. Phoenix, AZ.
Rouquette, F.M., Jr., J. Kerby, G. Nimr and K. Norman. 2012. Continuous versus rotational stocking of rye and ryegrass pastures at different stocking rates and forage allowance. 2012. ADSA-ASAS Abst. M68. Phoenix, AZ.
Rouquette, F.M., Jr., R. Randel, J. Paschal, T. Machado and C. Long. 2012. Relationship between carcass traits and tenderness with residual feed intake and residual average daily gain of Brahman steers. 2012. ADSA-ASAS Abst. T124. Phoenix, AZ.
Corriher, V., F. Rouquette, G. Smith and V. Haby. 2012. Persistence of alfalfa sod seeded in bermudagrass utilized for hay versus stocking. ASA, CSSA, and SSSA Abst. 257-27. Cincinnati, OH.
Neely, C., F. Rouquette, G. Smith, C. Morgan, F. Hons and W. Rooney. 2012. Integrating crimson clover (Trifolium incarnatum L.) and cowpea (Vigna unguiculata L. [Walp]) into grain sorghum (Sorghum bicolor L. [Moench]) cropping systems to improve crop yield, soil nitrogen, and soil carbon. ASA, CSSA, and SSSA Abst. 363-3. Cincinnati, OH.
Neely, C.B., F.M. Rouquette, Jr., G.R. Smith, C.L.S. Morgan, F.M. Hons, W.L. Rooney, B. Higginbotham. 2012. Green manuring and intercropping legumes: impacts on a high-biomass sorghum production system. Texas Plant Protection Association Abst. Bryan, TX.

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: Sustainable pasture-livestock systems are dependent upon comparative information and knowledge of soil fertility, forage DM production and persistence, forage nutritive value, forage utilization strategies, stocking methods, and animal nutritive requirements. Coastal (COS) and common (COM) bermudagrass (BG) pastures were stocked at different, controlled stocking rates (STK) beginning in 1969 to assess forage persistence, stand maintenance, and animal performance. From 1969 through 1984, all pastures received identical fertility rates at three STK. During the fall of 1984, a fertility regimen of nitrogen (N) plus overseeded annual ryegrass (RYG) vs. no-N plus overseeded annual clover (CLV) were superimposed on each BG x STK treatment. On average, COS pastures were stocked at about 1.0, 1.8, and 3.0 cow-calf pair/ac (1500 lbs/pair) and COM pastures were stocked at about 0.8, 1.4, and 2.0 pair/ac. Forage mass ranged from 500 to 1000 lb/ac at high STK, 1250 to 2000 lb/ac at medium STK, and more than 2500 lb/ac at low STK. Percent stand of both COS and COM was reduced by increased STK and no-N fertilizer. Bahiagrass was the primary non-BG invasive species on no-N pastures. Invasive BG ecotypes were more abundant at 73% and 86% of stand on high STK COS, respectively, with no-N + CLV and N + RYG. On COM pastures, invasive BG ecotypes were present at about 25% and 40%, respectively, on no-N + CLV and N + RYG; but ecotype invasion was not affected by STK. Within each STK x fertility regimen for both COS and COM, a 2- to 3-cm plant-root core was taken from visually-evident BG ecotype invasive areas. Approximately 125 representative plant-root cores were transferred to 10-cm clay plots for additional phenotype and genetic analyses. Each plant core was fingerprinted using amplified fragment length polymorphism (AFLP) markers, analyzed via coefficient of genetic similarity matrix, and clustered in genetically-related groups. A dendogram was created from a similarity matrix using appropriate statistical software. Using the AFLP markers, there were four distinct BG ecotype groups identified in COS pastures and five groups identified in COM pastures. There were several intermittent, non-related BG ecotypes in both COS and COM. The COS and COS-similar ecotypes were different from COM and COM-similar ecotypes in plant height, leaf length, leaf width, and leaf coarseness. The inflorescence characteristics of ecotypes for heading amount, raceme number, and raceme length ranked similar to those for growth traits. The originally planted COS and COM were used as standards for identifying genetic relationships with invasive ecotypes. Prolonged, high STK under continuous stocking can cause substantial stand loss of both COS and COM pastures. With the aggressive and persistent nature of the invasive ecotypes, BG species continued to provide a nearly complete ground cover under N-fertilization regimens. Under low STK, the originally-planted COS and COM made up about 70% to 75% of the BG. After 38-yrs of stocking, pastures were most sustainable when stocked at moderate to low STK and when receiving N fertilization. PARTICIPANTS: Drs. G.R. Smith and L.R. Nelson were collaborators on evaluation of legume and ryegrass for forage. Drs. R.D. Randel, L.O. Tedeschi and T.D.A. Forbes were collaborators in the animal nutrition and physiology components of this project. TARGET AUDIENCES: Research and Extension scientists and stakeholders in the humid southeastern US who are interested in stand maintenance and persistence of bermudagrass pastures on Coastal Plain soils as impacted by fertility regimen and stocking densities. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Input costs for fertilizer, feed, hay, etc for pasture-livestock systems should be evaluated for positive economic returns based on value of animal product for a specific vegetational region. As price per cwt of calves increase, management strategies will include added nitrogen fertilization of pastures to enhance forage mass and stocking rates. As cattle prices decline, management strategies include a reduction of all fertilization and especially phosphorus and potassium since nitrogen is responsible for grass production. The vegetational zone reflects climatic conditions and unique soil type-fertility status for forages. Stand maintenance and persistence of bermudagrass pastures in humid environments are diminished by reduced nitrogen fertilization and increased stocking rate. In the southern region of the US there are numerous bermudagrass ecotypes that may invade into hybrid or improved dry matter production bermudagrass pastures. Often, these invasive ecotypes will provide similar forage mass and nutritive value as common bermudagrass; however these ecotypes are less productive than improved cultivars such as Coastal bermudagrass. The primary impact of this long-term stocking experiment documents that bermudagrass sustainability and persistence are directly linked to soil fertility and defoliation regimens. Hybrid and improved cultivars of bermudagrass are most sustainable under moderate to high forage mass available for consumption and/or defoliation and with nitrogen fertilization.

Publications

Aguiar, A.D., L.O. Tedeschi, F.M. Rouquette, Jr., K. McCuistion, J.A. Ortega-Santos, R. Anderson, D. DeLaney and S. Moore. 2011. Determination of nutritive value of forages in south Texas using an in vitro gas production technique. Grass and Forage Science. doi:10.1111/j.1365-2494.2011.008098.x.
Rouquette, F.M., Jr., W.F. Anderson, K.R. Harris-Shultz and G.R. Smith. 2011. Stand maintenance and genetic diversity of bermudagrass pastures under different grazing management strategies during a 38-year period. Crop Sci. 51:2886-2894.
Rouquette, F.M., Jr., D.K. Hansen, G.W. Webb and G.D. Potter. 2011. Growth of yearling horses and costs related to pasture and supplemental feed alternatives. Forage & Grazinglands. Online. doi: 10.1094/FG-2011-0222-01-RS.
Nelson, L.R., J. Crowder and F.M. Rouquette, Jr. 2011. Registration of Nelson annual ryegrass. J. Plant Registrations 5:45-48.
Rouquette, F.M., Jr., J.L. Kerby, G. Nimr and K.D. Norman. 2011. Tifton 85 bermudagrass pastures stocked continuous or rotationally with weaned calves at two stocking rates. ASA-CSSA-SSSA. Abst. 107-8. San Antonio, TX.
Neely, C.B., F.M. Rouquette, Jr., G.R. Smith, C.L. Morgan, F. Hons, W.L. Rooney and B. Higginbotham. 2011. Legume contributions to soil and yield of high-biomass sorghum cropping systems. ASA-CSSA-SSSA. Abst. 225-5. San Antonio, TX.
Smith, G.R., F.M. Rouquette, Jr. and R. Jessup. 2011. Disease resistance in lablab bean. ASA-CSSA-SSSA. Abst. 235-6. San Antonio, TX.
Corriher, V.A., F.M. Rouquette, Jr. and G.R. Smith. 2011. Establishment of warm season annual legumes in bermudagrass sod or prepared seedbed. ASA-CSSA-SSSA. Abst. 237-8. San Antonio, TX.
Wiley, L.M., L.O. Tedeschi, T.D.A. Forbes, F.M. Rouquette, Jr., R.D. Randel, F.R.B. Ribeiro and S.E. Dowd. 2011. A comparison of ruminal and large intestinal microbial population of residual feed intake-indexed Brahman bulls under grazing conditions. ASAS-So. Sect. Abst. Corpus Christi, TX.
Rouquette, F.M., Jr., J.L. Kerby, G. Nimr and K.D. Norman. 2011. Supplement and stocking strategies for heavy-weight fall-born calves backgrounded on Tifton 85 bermudagrass. ADSA-ASAS Abst. T141. New Orleans, LA.
Williamson, B.C., M.L. Looper, F.M. Rouquette, Jr., G.E. Aiken, S.F. Tabler, J.B. Wolley and C.F. Rosenkrans. 2011. Effects of stocking rate and supplementation on carcass traits of beef cattle grazing winter annual forages. ADSA-ASAS Abst. T146. New Orleans, LA.
Rouquette, F.M., Jr., W.F. Anderson, K.R. Harris-Shultz and G.R. Smith. 2011. Impact of long-term stocking rates and fertility strategies on stand maintenance and genetic diversity of bermudagrass pastures. Beef Cattle Res. in TX. http://animalscience.tamu.edu/academics/beef/research/index.htm

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Pasture-livestock management strategies to enhance sustainability as well as biological and economic efficiencies are dependent upon baseline, comparative databases for soil fertility, forage DM and persistence, forage nutritive value, utilization strategies, stocking rates, supplementation, and resultant animal performance. Tifton 85 bermudagrass has enhanced nutritive value and DM production characteristics that can provide acceptable stocker gains per animal and per acre. A two-year study with Tifton 85 was conducted to compare gain per animal (ADG) and gain per acre for stockers at two stocking rates (STR) under both continuous (CONT) and rotational (ROTN) stocking. The ROTN consisted of an 8-paddock system wherein stockers were moved to a new paddock after a 2-day residence, and with a 14-day deferment period. Within each year as well as the two-year average, there was no difference in ADG between CONT (1.30 lbs/da) and ROTN (1.24 lbs/da). Fall-born Simmental-sired steers and heifers gained the same at 1.26 lbs/da. Stockers on low STK of 3.9 hd/ac had ADG of 1.50 lbs/da which was different than those on high STK of 5.3 hd/ac with an ADG of 1.06 lbs/da. The two-year average gain per acre was 683 lbs for low STK and 643 lbs for high STK. For this class of stockers, the low STK of about 4 hd/ac had both biological and economic advantage over high STK. A three-year grazing study comparing Tifton 85 bermudagrass pasture (PAS) and a daily 36% protein supplement (SUP) of .4% body weight (BW) soybean meal:cracked corn (2:1) showed a .62 lbs/da increase in ADG using SUP for fall-born calves in Trial 1. The PAS ADG of 1.23 lb/da was increased to 1.84 lb/da with 3.3 lbs/da SUP, and the conversion of SUP:extra gain was 5.6:1. At stocking rates of 4.6 to 5.0 700-lb stockers/ac, gain per acre was increased from 523 lbs to 831 lbs/ac with SUP. In Trial 2, stocking rate (SR) x SUP showed decreased ADG as SR increased from 5 to 9 700-lb calves/ac. With increasing SR, extra gain due to SUP increased which resulted in improved SUP:extra gain ratios of 6.2:1, 3.3:1, and 3.4:1, respectively, for low, medium, and high SR. Gain per acre was maximum at medium SR plus SUP at 1161 lbs/ac during this 90-day period. During each of three years, fall-born calves were stocked at five to six 700 lb hd/ac on Tifton 85 bermudagrass (PAS) from July through September and received varying, daily protein or energy supplementation (SUP). In Trial 1, cracked corn (CRN) and pelleted corn gluten (GLU) fed daily at 0.8% body weight (BW) resulted in the greatest ADG of about 2 lbs/da. Other SUP of 0.4% BW of GLU, CRN, or soybean meal:corn (2:1) resulted in ADG of about 1.6 lbs/da. All SUP had higher ADG than PAS at about 0.8 lb/da. Stocker gain per acre during this 90-da period ranged from 412 lbs/ac for PAS to 1237 lbs/ac for 0.8% BW CRN. In Trial 2, GLU fed at either 0.4% or 0.8% BW resulted in an additional 0.8 to 0.4 lbs/da compared to PAS. In Trial 2, supplement to extra gain was not as cost-effective as in 2005, and ranged from 3.3:1 with adequate available forage to nearly 16:1 for 0.8% BW with restricted forage. PARTICIPANTS: Dr. G.R. Smith, Texas AgriLife Research Overton; Dr. T.D.A. Forbes, Texas AgriLife Research Uvalde; Dr. R.D. Randel, Texas AgriLife Research Overton TARGET AUDIENCES: Research and extension scientists and stakeholders concerned and interested in stocking strategies and stocking rates for stocker cattle on Tifton 85 bermudagrass pastures. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Increased costs of fertilizers and feed have caused enhanced management awareness for efficiency of pasture and livestock production. One aspect of increased biological efficiency and economic returns is associated with continuous ownership of calves from weaning to the feeder stage. These management strategies are associated with stocker performance on either winter annual forages such as small grains and ryegrass and/or summer perennial grasses such as Tifton 85 bermudagrass. Research results from these stocker studies provide a comparative database for gain per animal and gain per acre. Calculations using purchase-sales prices and stocking rates allows for estimation of economic returns and subsequent risk.

Publications

Forbes, T.D.A., F.M. Rouquette, Jr., L.O. Tedeschi, R.D. Randel and F.R.B. Ribeiro. 2010. A comparison of anatomical and compositional differences of residual feed intake (RFI)-indexed Brahman bulls Undergrazing conditions. J. Anim. Sci. 88(E-Suppl. 2):57 (Abst. # M128).
Neely, C.B., F.M. Rouquette, Jr., G.R. Smith, C.L. Morgan and W.L. Rooney. 2010. Using legumes to reduce nitrogen fertilization and enhance soil nitrogen and carbon for grain sorghum cropping systems. Texas Plant Protection Association.
Forbes, T.D.A., A.D. Aguiar, L.O. Tedeschi, F.M. Rouquette, Jr., G.E. Carstens and R.D. Randel. 2010. Performance and efficiency on pasture of cattle with divergent phenotypes for residual feed intake. Proceedings of the 4th Grazing Livestock Nutrition Conference. July 9-10, 2010, Estes Park, CO. Abst. p. 207.
Hughes, C.A., J.A. Carter, T.D.A. Forbes, F.M. Rouquette, Jr., L.O. Tedeschi, R.D. Randel and F.R.B. Ribeiro. 2010. Use of real-time ultrasound (RTU) measurements and carcass traits to assess internal fat in residual feed intake (RFI)-indexed Brahman bulls under grazing conditions. J. Anim. Sci. 88(E-Suppl. 2):700 (Abst. # W352).
Rouquette, Jr., F.M., W.F. Anderson, K. Harris-Shultz and G.R. Smith. 2010. Phenotype traits of bermudagrass ecotypes from pastures stocked at different intensities during a 40-year period. ASA-CSSA-SSA. Abst. 81-4. Long Beach, CA.
Smith, G.R. and F.M. Rouquette, Jr. 2010. Improvement of seed production traits in lablab bean. ASA-CSSA-SSSA. Abst. 291-4. Long Beach, CA.
Rouquette, Jr., F.M. and G.R. Smith. 2010. Review: Effects of biological nitrogen fixation and nutrient cycling on stocking strategies for cow-calf and stocker programs. Prof. Anim. Sci. 26:131-141.
Curley, K.O., Jr., D.A. Neuendorff, A.W. Lewis, F.M. Rouquette, Jr., T.H. Welsh, Jr. and R.D. Randel. 2010. The effectiveness of vasopressin as an ACTH secretogogue in cattle differs with temperament. Physiology and Behaviour 101:699-704. PM ID:20728458.
Aguiar, A.D., L.O. Tedeschi, F.M. Rouquette, Jr., T.D.A. Forbes, C.M. Hensarling and R.D. Randel. 2010. Statistical variation in predicting dry matter intake of Brahman bulls using then-alkane technique. J. Anim. Sci. 88(E-Suppl. 2):57 (Abst. # M127).

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: Pasture-livestock management strategies to enhance sustainability as well as biological and economic efficiencies are linked to soil-plant-animal relationships. These strategies are dependent upon baseline, comparative databases for soil fertility, forage DM and persistence, forage nutritive value, utilization strategies, stocking rates, and resultant animal performance. Stocking strategies for cool-season annual grass pastures of small grain + ryegrass may be enhanced by consideration of the bimodal forage DM production characteristics. With a minor forage DM peak in the fall and a major forage DM peak during March-May, Maton rye + TAM-90 annual ryegrass pastures were evaluated for forage utilization and stocker gains by: 1) initial stocking on Dec 22 (EARLY) at Fixed stocking rates (SR) of low (1.5 hd/ac) and medium (2.2 hd/ac); 2) EARLY stocking using Variable SR increasing from low to medium (1.5 to 2.3 hd/ac) and from low to high (1.5 to 3.0 hd/ac); and 3) deferred stocking until Jan 20 (DEFER) at Fixed SR of medium (2.1 hd/ac) and high (2.7 hd/ac). Stocker ADG from initiation to termination on May 4 using two replicate pastures for each treatment for EARLY-Fixed SR was 3.4 lbs/da for low and 2.4 lbs/da for medium SR. Both the EARLY-Variable SR of low to medium and the DEFER-Fixed medium SR resulted in stocker ADG of 2.9 lbs/da. The EARLY-Variable SR of low to high at 2.3 lbs/da was similar to the EARLY-Fixed medium animal gains. Stocker ADG from pastures that were DEFER-Fixed high SR had the lowest performance at 1.5 lbs/da. On these Fixed, high SR pastures, forage defoliation was substantially severe to reduce forage growth during April; hence, most stockers showed negative ADG during the last 30 days on pasture. From an economic management strategy, stockers on these high SR pastures should have been removed during early April. Tifton 85 bermudagrass was stocked at two SR (2.9 and 4 hd/ac) from June 12 to October 3 and stocker ADG and gain/ac were compared for continuous (CONT) and rotational (ROTN) stocking. The ROTN stocking included an 8-paddock system with cattle moved after 2 days residence on all SR. Replicate pastures gave near identical ADG for CONT and ROTN stocking with 1.94 lbs/da at low SR for both stocking methods and 1.50 lbs/da at high SR for both stocking methods. Resultant gain per acre for the 114-day period was 640 lbs/ac for low SR and 685 lbs/ac for high SR. Although additional factors may require consideration, the immediate economically viable stocking strategy would favor the low SR methods. The high SR pastures were subject to increased biological risks associated with climatic factors and reduced forage availability, and increased economic risks associated with additional input costs for cattle. Stocking strategies for post-weaning, continuous ownership phases can provide additional, positive economic returns to management if pasture costs associated with fertilization are not excessive in relationship to price of cattle. PARTICIPANTS: Dr. G.R. Smith, Texas AgriLife Research Overton; Dr. T.D.A. Forbes, Texas AgriLife Research Uvalde; Dr. R.D. Randel, Texas AgriLife Research Overton TARGET AUDIENCES: Research and extension scientists and stakeholders concerned and interested in stocking strategies and stocking rates for stocker cattle on either small grain + ryegrass pastures or Tifton 85 bermudagrass pastures. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Increased costs of fertilizers and feed have caused enhanced management awareness for efficiency of pasture and livestock production. One aspect of increased biological efficiency and economic returns is associated with continuous ownership of calves from weaning to the feeder stage. These management strategies are associated with stocker performance on either winter annual forages such as small grains and ryegrass and/or summer perennial grasses such as Tifton 85 bermudagrass. Research results from these stocker studies provide a comparative database for gain per animal and gain per acre. Calculations using purchase-sales prices and stocking rates allows for estimation of economic returns and subsequent risk.

Publications

Aquiar, A.D., L.O. Tedeschi, F.M. Rouquette, Jr., T.D.A. Forbes, C.M. Hensarling and R.D. Randel. 2009. Predicting dry matter intake of grazing Brahman bulls selected for high and low feed efficiency. J. Anim. Sci. 87(E-Suppl.2):223.
Lancaster, P.A., G.E. Carstens, D.H. Crews, T.H. Welsh, Jr., T.D.A. Forbes, D.W. Forrest, L.O. Tedeschi, R.D. Randel, and F.M. Rouquette, Jr. 2009. Phenotypic and genetic relationships of residual feed intake with performance and ultrasound carcass traits in Brangus heifers. J. Anim. Sci. 87:3887-3896.
Rouquette, F.M., Jr. and G.R. Smith. 2009. Effects of biological N fixation and nutrient cycling on stocking strategies for cow-calf and stocker programs. J. Anim. Sci. 87 (E-Suppl)
Rouquette, F.M., Jr., L.A. Redmon, G.E. Aiken, G.M. Hill, L.E. Sollenberger, and J. Andre. 2009. ASAS Centennial Paper: Future needs of research and extension in forage utilization. J. Anim. Sci. 87:438-446.
Smith, G.R., F.M. Rouquette, Jr., and I.J. Pemberton. 2009. Lablab Bean: A new multi-purpose forage and seed crop for Texas. Proceedings of the 14th Australasian Plant Breeding Conference. 10-14 August 2009 Cairns Convention Centre, Tropical North Queensland, Australia.

Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: Sustainable and efficient pasture-livestock production systems are uniquely interrelated with soil-plant-animal relationships. Management strategies to optimize biological and economic returns are dependent upon comparative knowledge of soil fertility, forage DM production and persistence, forage nutritive value, forage utilization strategies, stocking methods, and animal requirements. A long-term stocking rate experiment on Coastal (COS) and common (COM) bermudagrass was initiated in 1969 to assess forage persistence and stand maintenance using an array of cool-season annual clovers and/or annual ryegrass. In the fall of 1984, a fertility regimen of nitrogen (N) plus ryegrass compared to no-N plus clover was implemented for both COS and COM to quantify the effect of stocking intensity on impact of nutrient cycling on forage and animal parameters. A primary, sustainable forage trait measurement was that of assessing the genetic makeup of bermudagrass and species composition diversity in the various stocked COS and COM pastures. Pastures were stocked from about mid-February through September with average stocking rates of 0.8, 1.4, and 2.0 1500-lb cow-calf pair (PAIR) per acre for COM pastures and 1.0, 1.8, and 3.0 PAIR per acre for COS pastures. These stocking intensities resulted in available forage DM for consumption at about 500 to 1000 lbs/ac for high (HI), 1250 to 2000 lbs/ac for moderate (MD), and > 2500 lbs/ac for low (LO) stocked pastures. All pastures were sub-divided into 10 blocks for visual scoring of species composition by two observers. For COM pastures receiving N + ryegrass, there were no differences in bermudagrass stand among stocking intensities with an average of about 60-65% COM, and 35-40% other bermudagrass ecotypes. For COM pastures receiving no N + clover and stocked at HI or MD intensities, there was about 25% COM, 25% other bermudagrass ecotypes, and 50% bahiagrass. At the LO stocked COM pastures, there was about 75% COM and 25% other bermudagrass ecotypes. For the COS pastures receiving N + ryegrass and stocked at the HI intensity, there was about 15% COS and 85% other bermudagrass ecotypes; whereas, at the MD and LO stocking intensities, there was about 75% COS and 25% other bermudagrass ecotypes. The long-term stocked COS pastures receiving no N + clover had about 20 to 25% COS on either HI or MD stocking intensities and about 80% COS on the LO stocked pastures. Other bermudagrass ecotypes had invaded at the level of about 20% on LO to 70% on HI stocked pastures. The MD stocked COS pastures were also invaded with about 30% bahiagrass. Substantial genetic diversity of bermudagrass ecotypes was indicated by polymorphic bands in both COM and COS pastures as shown from an Amplified Fragment Length Polymorphism analyses. Both genetic and phenotypic observations of plants from MD and HI stocked pastures indicated presence of a natural common x Coastal hybrid development. Stand maintenance of desired cultivars of bermudagrass may be best achieved using low to moderate stocking rates that allowed for > 2500 lbs/ac DM of available forage, and especially if N fertilizer was drastically reduced or eliminated. PARTICIPANTS: Drs. G.R. Smith and V.A. Haby were collaborators on soil chemistry and analyses, and legume cultivar components of this project. Drs. T.D.A. Forbes and R.D. Randel were participants in the animal nutrition and physiology components of this project. TARGET AUDIENCES: Research and extension scientists and stakeholders concerned and interested in nutrient cycling and stand maintenance of bermudagrass on Coastal plain soils as affected by stocking densities and fertility regimen. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Increased costs of energy-related products such as fertilizer, feed, and fuel have created major management shifts in pasture-livestock production operations. Periodic soil sampling at multiple depths has verified minimal soil nutrient contamination from fertility regimens or stocking rates from long-term stocking experimentation. Stand maintenance of bermudagrass was best for low stocked pastures which had > 2500 lbs/ac DM of available forage. With increasing stocking rates on either Coastal or common bermudagrass pastures, there was an increasing presence of other bermudagrass ecotypes. Bahiagrass proved to be a major invader of common bermudagrass pasture that had not received N fertilizer for the previous 25 years. The persistence and competitiveness of bahiagrass on non-N fertilized, Coastal Plain soils was substantiated in these long-term stocked pastures. Cow and calf performance on a per head basis was not restricted due to forage species diversity and invasion by other ecotypes. However, gain per acre declined as Coastal bermudagrass pastures were replaced with other bermudagrass ecotypes.

Publications

Smith, G.R., G.W. Evers, F.M. Rouquette, Jr., and I.J. Pemberton. 2008. Improvement of reseeding in crimson clover. North American Alfalfa Improvement & Trifolium Conference. Dallas, Texas. (Abst) 20:10.
Wickersham, T.A., F.M. Rouquette, Jr., J.E. Sawyer, and R.O. Dittmar III. 2008. Effect of urea inclusion and cooking time on intake of blocks containing greasy cottonseed meal by beef cows. Am. Soc. Anim. Sci. Indianapolis, IN. (Abst) 137:TH49.
Smith, G.R., F.M. Rouquette, Jr., and I.J. Pemberton. 2008. Registration of Rio Verde lablab. J. of Plant Reg. 2:15.
Behrends, S.M., R.K. Miller, F.M. Rouquette, Jr., R.D. Randel, B.G. Warrington, T.D.A. Forbes, T.H. Welsh, Jr., G.E. Carstens, H. Lippke, and J.W. Holloway. 2008. Relationship of temperament, growth, carcass characteristics and tenderness in beef steers. http://dx.doi.org/10.1016/j.meatsci.2008.09.003.
Rouquette, F.M., Jr., L.A. Redmon, G.E. Aiken, G.M. Hill, L.E. Sollenberger, and J. Andrae. 2008. Animal Science Centennial Symposium: Research and extension needs in forage utilization in the future. Am. Soc. Anim. Sci. Indianapolis, IN. (Abst) 545:155.
Rouquette, F.M., Jr., T.D.A. Forbes, B.G. Warrington, J.W. Holloway, K.R. Hawks, R.K. Miller, and C.R. Long. 2008. Tifton 85 bermudagrass and supplemental corn gluten for direct harvest off-pasture of Bonsmara and Simmental crossbred steers. So. Assn. Agric. Sci. Dallas, Texas. (Abst) 42:76.
Rouquette, F.M., Jr. 2008. Pasture-beef cattle management options with increased costs of fertilizer, feed gains and fuel:stocking strategies and nutrient cycling. Res. Center Tech Report 2008-01:27-52.
Rouquette, F.M., Jr., W.F. Anderson, G.R. Smith, and V.A. Haby. 2008. The effect of long-term stocking intensities and fertility regimen on stand purity in bermudagrass pastures. Am. Soc. Agron. Houston, Texas. (Abst) 568-5:289.
Forbes, T.D.A, F.M. Rouquette, Jr., B.G. Warrington, K.R. Hawks, R.K. Miller, and J.W. Holloway. 2008. Effect of corn supplementation on pasture performance and carcass characteristics of cross-bred Bonsmara steers grazing winter annual pasture. So. Assn. Agric. Sci. Dallas, Texas. (Abst) 43:76.
Smith, G.R. F.M. Rouquette, Jr., G.W. Evers, G.A. Peterson, and W. Alison. 2008. Neches White Clover: A new cultivar for the U.S. Southern Region. Am. Soc. Agron. Houston, Texas. (Abst) 726-3:341.

Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: Biological and economic efficiencies of livestock performance from pastures are dependent upon experiences as well as information on soil fertility, seasonal and total forage DM forage, nutritive value, stocking rate, stocking strategies, and activity requirements of livestock. A long-term, nutrient cycling experiment was initiated in fall 1984 to assess N vs no-N fertilizer on both common and Coastal bermudagrass pastures. Soil measurements to quantify and account for NO3-N, P, K, and pH showed positive relationships with fertilizer applied; however, all soil nutrients were significantly lower than threshold environmentally-sensitive levels. Omission of N fertilizer and high stocking rates for more than 20 years allowed invasion by bahiagrass and mixed genotypes of common bermudagrass. Pastures moderately to low stocked and overseeded with clovers and no-N, showed acceptable stand maintenance and reduced gain/acre of about 30% compared to N-fertilized pastures. Tifton 85 bermudagrass was stocked with either 8-mo fall-born 1/2 Simmental x 1/4 Brahman x 1/4 Hereford (SIMX) steers and heifers or 15-mo Bonsmara (BONX) steers from mid June thru September and received only pasture (PAS) or a daily, hand-fed supplement of corn gluten at .8% BW (.8 GLU). During two consecutive years, BONX had higher respective ADG, 1.58 and 1.31 lbs/da, compared to SIMX at 1.17 and 1.04 lbs/da. At stocking rates (SR) of 4 hd/ac in year 1 and 5 hd/ac year 2, the 2-year average gain/ac for .8 GLU was 750 lbs/ac and for PAS was 460 lbs/ac. The additional 300 lbs/ac gain using .8% GLU has management implications concerning SR and risk aversion during the summer. Yearling SIMX steers and heifers were stocked on Maton rye plus TAM 90 annual ryegrass (RYRG) from 1-08-06 until 5-08-07 to assess performance on pasture (PAS) vs supplementation. Hand-fed daily supplements included .4% BW, .8% BW, and 1.2% BW cracked corn (CRN), and .4% BW and .8% BW corn gluten (GLU). The ADG from two replicate pastures for SIMX were 2.91, 3.11, 3.31, 3.40, 3.45, and 3.75 lbs/d, respectively, from PAS, .4 CRN, .4 GLU, .8 CRN, .8 GLU, and 1.2 CRN. With SR set at 2 hd/ac for 120-d, gain/ac for SIMX ranged from 700 lbs/ac on non-supplemented PAS to 900 lbs/ac on 1.2% CRN. The BONX yearling steers were stocked at 2 hd/ac on both RYRG and MAX Q-Jesup Tall Fescue, and received PAS vs .8 CRN on two replicate pastures per treatment. The ADG from RYRG was 2.36 lb/da on PAS and 2.78 lbs/da on .8 CRN for 120-d with respective gain/ac of 566 lbs/ac (PAS) and 667 lbs/ac (.8 CRN). Performance from tall-fescue stocked for 90 days was 2.58 lbs/da (PAS) and 3.01 lbs/da (.8 CRN) with gain/ac at 456 lbs/ac (PAS) and 542 lbs/ac (.8 CRN). Increased ADG and gain/ac using supplementation on cool-season pastures were used largely in substitution capacities. Costs associated with supplement, method of delivery, and supplement:extra gain ratio are factors governing economy of implementation of supplementation strategies. PARTICIPANTS: Dr. G.R. Smith and Dr. V.A. Haby were collaborators on soil chemistry and legume cultivar components of this project. Dr. T.D.A. Forbes and Dr. R.D. Randel were collaborators on the animal nutrition and physiology components of this project. TARGET AUDIENCES: Research and extension scientists and stakeholders concerned with biological and economic information resulting from this project.

Impacts
Increased awareness and concern pertaining to environmental issues and profitable livestock enterprises continue to receive primary emphases with long-term nutrient cycling and birth-to-harvest performance. Bermudagrass pastures receiving N-fertilization and overseeded with annual ryegrass vs no-N fertilization and overseeded with clovers have been grazed at three stocking rates with cows and calves for a 23-year period. Regular soil analyses verified the low impact of fertilizer N, P, and K as well as stocking rate on soil nutrient contamination. High stocked pastures without N fertilization have exhibited significant forage species composition shifts toward increased percent bahiagrass and common bermudagrass ecotypes. Stockers grazing rye + ryegrass pastures with or without energy supplementation and gains of 3 lb/hd/da were available for either direct harvest at stocking termination in May or a reduced feedlot residence. Stockers stocked on Tifton 85 bermudagrass at 5 hd/ac with and without a protein supplement resulted in gain/ac of about 750 lbs/ac during a 100-day grazing period. The ADG of more than 1.5 lbs/da provided a source of cattle which required less feedlot residence. Costs of fertilizer and feed rations demand reduced inputs or increased efficiency of forage utilization and animal performance. These cow-calf and stocker experiments provide comparative databases for economic decisions and directions for new research.

Publications

Nelson, L.R., J. Crowder, F.T. Tarver, G.W. Evers, and F.M. Rouquette, Jr. 2007. Registration of TAMTBO annual ryegrass. J. Plant Registrations 1:127-128.
Forbes, T.D.A. and F.M. Rouquette, Jr. 2007. Forage-animal interface:grazing behavior and nutrient intake. Encyclopedia of Animal Science. Taylor & Francis Group, Madison Ave, New York, NY. http://www.informaworld.com.
Falkenberg, S.M., R.K. Miller, J.W. Holloway, F.M. Rouquette, Jr., R.D. Randel, G.E. Carstens, B.G. Warrington, T.D.A. Forbes, and H. Lippke. 2007. Evaluation of the relationship between temparment, growth, carcass characteristics and tenderness in beef steers. 2007 Beef Cattle Research in Texas. http://coals.tamu.edu. pp. 43-60.
Rouquette, F.M. Jr., K.D. Norman, and L. Ortega. 2007. Economic perspective of stocking rates and supplementation for stocker steers and heifers grazing rye and ryegrass pastures. 2007 Beef Cattle Research in Texas. http://coals.tamu.edu. pp. 145-152.
Rouquette, F.M. Jr., J.L. Kerby, and G.H. Nimr. 2007. Influence of continuous vs rotational stocked rye-ryegrass pastures at different stocking rates on steer performance. 2007 Beef Cattle Research in Texas. http://coals.tamu.edu. pp. 153-158.
Rouquette, F.M. Jr., J.L. Kerby, G.H. Nimr, and J.M. Vendramini. 2007. Stocking rate and supplement level effects on stockers grazing rye-ryegrass pastures. 2007 Beef Cattle Research in Texas. http://coals.tamu.edu. pp. 159-164.
Rouquette, F.M. Jr., I.T. Brigman, G.E. Carstens, and R.K. Miller. 2007. Winter pasture stocking rate effects on carcass composition and meat tenderness of two breedtypes. 2007 Beef Cattle Research in Texas. http://coals.tamu.edu. pp. 165-172.
Smith, G. R., I. J. Pemberton, F. M. Rouquette, Jr., and G. W. Evers. 2007. Forage legumes for Texas and the US southern region. Proceedings 2007 Southern Pasture and Forage Crop Improvement Conference. Tallahassee, Florida. http://spfcic.okstate.edu/proceedings/2005/proceed.htm.
Hawks, K.R., R.K. Miller, T.D.A. Forbes, F.M. Rouquette, Jr., J.W. Holloway, and B.G. Warrington. 2007. Maximizing carcass characteristics of grass-and grain-fed Bonsmara steers using electrical stimulation. J. Anim. Sci. San Antonio, TX. J. Anim. Sci. 85 (Suppl. 1):601. (abstract).
Gutiernez-Banuelos, J., S. Prince, D.R. Tolleson, G.E. Carstens, T.D.A. Forbes, F.M. Rouquette, Jr., R.D. Randel, and T.H. Welsh. 2007. Use of fecal near-infrared reflectance spectroscopy to predict residual feed intake in growing calves. So. Assn. Agric. Scientist, Anim. Sci. Mobile, AL. J. Anim. Sci. 85 (Suppl. 2):32. (abstract).
Rouquette, F.M., Jr. and L. Ortega. 2007. Economic strategies for stocking rates and supplementation of stockers grazing rye-ryegrass pastures. J. Anim. Sci. San Antonio, TX. J.Anim. Sci. 85 (Suppl. 1):335. (abstract).

Progress 01/01/06 to 12/31/06

Outputs
Management strategies for sustainable and economic livestock performance from pastures are linked to soil-plant-animal relationships which influence forage production and utilization. Some of these strategies include knowledge of soil nutrient status, forage cultivars, stocking rate, stocking method, and class of livestock responses. During the past 22 years, nutrient cycling studies have been conducted with common (CM) and Coastal (CS) bermudagrass pastures. These warm-season perennial grass pastures were overseeded in the autumn with clover (CLV) without nitrogen (N) fertilizer or annual ryegrass (RYG) plus fertilizer N. Three stocking rates (SR) of cows and calves grazing from mid-February through September each year were used on each treatment combination of CM and CS plus CLV-N and RYG+N. Soil phosphorus (P), nitrate-nitrogen (NO3-N), potassium (K), and pH were parameters measured during this period. During an 11-year period without application of P fertilizer, soil P remained relatively constant at about 30 ppm. Under low SR, soil P was depleted faster in the soil profile compared to high SR. Soil NO3-N concentrations were strongly related to fertilizer N application. Annual rates of more than 400 lbs/ac N resulted in NO3-N soil levels of 15 to 30 ppm; whereas, annual rates of about 200 lbs/ac had soil NO3-N levels of 5-10 ppm. Pastures that did not receive N fertilizer during a 22-year period had soil NO3-N levels of less than 5 ppm. Stocking rate was not a contributing factor to soil NO3-N levels. Soil pH was significantly affected (decreased) with annual applications of N fertilizer (34-0-0), and was not affected by bermudagrass species nor SR. Bermudagrass pastures should be soil sampled on a routine basis (at 1 to 3 year intervals), and during the same season to determine fertilizer and lime requirements. Pastures overseeded with clover and without added N fertilizer for 22 years showed some indications of weed invasion and slightly reduced DM production compared to N-fertilizer pastures. However, costs of beef production for bermudagrass pastures on a fertilizer cost per pound of calf gain basis favored the CLV and non-N fertilized pastures compared to the N+RYG pastures. Winter-born and fall-weaned calves from nutrient cycling experiments were used to ascertain relationships between stocking rates and level of supplementation (SUP) on stocker calves grazing Maton rye + TAM-90 annual ryegrass (PAS). Steers and heifers grazed PAS only or with daily SUP at 0.4% or 0.8% BW of a cracked corn plus Rumanian ration. Each PAS + SUP level (n=3) were stocked at 3 levels of 1.5, 2.1, and 3 550-lb hd/ac from mid-December to mid-May. Without SUP, stockers gained 2.80, 2.21, and 1.13 lbs/da with respective, increasing SR, and gain/ac was optimized at 700 lbs/ac at 2.1 hd/ac. Using SUP increased ADG to more than 3 lbs/da on both low and medium SR, and increased ADG from 1.1 (PAS) to 2.0 lbs/da (SUP) at both 0.4 and 0.8% SUP rates. Biological efficiencies of SUP:extra gain was optimized at high SR, and economic efficiencies to reduce risks of SR depended on ration cost and method of delivery.

Impacts
Long-term grazing studies on bermudagrass pastures comparing nitrogen fertilizer and overseeded ryegrass vs no nitrogen and overseeded clover showed minimal risks of contamination due to fertility or stocking rates on Coastal Plain sandy soils. The nitrogen-fertilized pastures produced more forage DM, allowed for higher stocking rates, and had more vigorous bermudagrass stand. The non-nitrogen fertilized pastures overseeded with clovers produced the most economical costs of calf gain.

Publications

Smith, G. R. I. J. Pemberton, F. M. Rouquette, Jr., and G. W. Evers. 2006. Progress in breeding forage legumes for disease resistance and adaptation to adverse environments in Texas and the US southern region. 13th Australasian Plant Breeding Conference Proceedings. Christchurch, New Zealand. April 18-21, 2006.
Silveira, M.L., F.M. Rouquette, Jr., J.L. Kerby, G.H. Nimr, V.A. Haby, and G.R. Smith. 2006. Changes in soil phosphorus in common and coastal bermudagrass pastures during 35 years of various stocking and fertility regimens. Overton Res. Ctr. Tech. Rept. 2006-1:39-40.
Silveira, M.L., F.M. Rouquette, Jr., J.L. Kerby, G.H. Nimr, V.A. Haby, and G.R. Smith. 2006. Changes in soil nitrate-nitrogen of common and coastal bermudagrass pastures subjected to long-term stocking rates and fertility regimens. Overton Res. Ctr. Tech. Rept. 2006-1:41-42.
Silveira, M.L., F.M. Rouquette, Jr., J.L. Kerby, G.H. Nimr, V.A. Haby, and G.R. Smith. 2006. Changes in soil potassium concentrations in the top 6-inch soil depth in common and coastal bermudagrass pastures during 35 years of stocking and fertility regimens. Overton Res. Ctr. Tech. Rept. 2006-1:43-44.
Silveira, M.L., F.M. Rouquette, Jr., J.L. Kerby, G.H. Nimr, V.A. Haby, and G.R. Smith. 2006. Soil depth distribution of phosphorus in coastal bermudagrass pastures subjected to long-term stocking rates and fertility regimens. Overton Res. Ctr. Tech. Rept. 2006-1:45-46.
Silveira, M.L., F.M. Rouquette, Jr., J.L. Kerby, G.H. Nimr, V.A. Haby, and G.R. Smith. 2006. Soil depth distribution of nitrate-nitrogen in coastal and bermudagrass pastures subjected to long-term stocking rates and fertility regimens. Overton Res. Ctr. Tech. Rept. 2006-1:47-48.
Silveira, M.L., F.M. Rouquette, Jr., J.L. Kerby, G.H. Nimr, V.A. Haby, and G.R. Smith. 2006. Soil depth distribution of potassium in common and coastal bermudagrass pastures under 30 years of grazing at different stocking rates. Overton Res. Ctr. Tech. Rept. 2006-1:49-50.
Rouquette, F.M., Jr., J.L. Kerby, G.H. Nimr, I.J. Pemberton, and G.R. Smith. 2006. Time of harvest of lablab and cowpeas on production and nutritive value of leaf and stem components. Overton Res. Ctr. Tech. Rept. 2006-1:75-76.
Rouquette, F.M., Jr., J.L. Kerby, G.H. Nimr, I.J. Pemberton, and G.R. Smith. 2006. Effect of seeding rate of cowpeas and lablab on dry matter production and nutritive value. Overton Res. Ctr. Tech. Rept. 2006-1:77-78.
Rouquette, F.M., Jr., C.R. Stichler, and J.M. Murphy. 2006. Seven-year bermudagrass production at Pecos, Texas under irrigation. Overton Res. Ctr. Tech. Rept. 2006-1:85-86.
Rouquette, F.M., Jr., J.L. Kerby, G.H. Nimr, and J.M. Vendramini. 2006. Stocking rate and level of supplement effects on performance of stocker steers and heifers grazing rye-ryegrass pastures. Overton Res. Ctr. Tech. Rept. 2006-1:107-108.
Rouquette, F.M., Jr. and Leonardo Ortega. 2006. Economic assessment of stockers grazing rye-ryegrass pastures at three stocking rates and three levels of supplement. Overton Res. Ctr. Tech. Rept. 2006-1:109-110.

Progress 01/01/05 to 12/31/05

Outputs
Management considerations employed to optimize biological and economic livestock performance and to sustain pasture productivity are inseparately linked to strategies to enhance forage production and utilization. Strategies include stocking rate, stocking method, defoliation regimen, forage cultivar, and soil nutrient management. For the past 21 years, nutrient management-nutrient cycling experiments have been conducted with common (CM) and coastal (CS) bermudagrass pastures. Both CM and CS pastures were overseeded in separate pastures with Apache arrowleaf clover (ARL) without nitrogen (N) fertilizer or TAM-90 annual ryegrass (RYG) plus N fertilizer and all species combinations stocked with cows and calves at three stocking rates (LO, ME, HI) from February through September each year. Pastures receiving N and overseeded with RYG produced more forage, supported higher stocking rates, and had greater liveweight gains per acre than pastures receiving no N and overseeded with ARL. Summer calf gains/acre were more than 25% higher on CS compared to CM pastures. From February through September and at ME and HI stocking rates, calf gain/acre from RYG+N pastures was 25 to 40% higher than calf gains from ARL without N. The CS pastures with RYG+N produced 1050 and 1150 lbs calf gain/ac, respectively, when stocked at 2.3 and 4.1 1500-lb animal units/ac. The CM pasture with RYG+N produced 900 and 950 lbs calf gain/ac, respectively, when stocked at 1.5 and 3.3 1500-lb animal units/ac. Fertilizer costs/lb calf gain, however, ranged from $0.09 to $0.16/lb on non-N fertilized pastures and $0.18 to $0.35/lb on N-fertilized pastures. Fall born steers and heifers weaned in June grazed Tifton 85 bermudagrass with and without supplementation (SUPL) until mid-September. Calf ADG from pasture only (PAS) was 1.56 lbs/da. Daily SUPL with 0.4% BW of either a 2:1 (soybean meal:cracked corn), cracked corn, or pelleted corn gluten produced, respective, ADG of 2.08, 2.07, and 1.97 lbs/da. Daily SUPL with 0.8% BW cracked corn or pelleted corn gluten had ADG of 2.41 and 2.22 lbs/da, respectively. Initial stocking rate was five 770-lb calves per acre. Efficiency of SUPL:extra gain was about 7.8:1 at the 0.4% BW level and about 9:1 at the 0.8% BW level. Thus, cost/lb extra gain due to corn or corn gluten SUPL was about $0.45 to $0.55/lb. Winter born calves weaned in October grazed Maton rye+TAM-90 annual ryegrass from mid-December to mid-May. Steers and heifers were grazed at 1.5, 2.1, and 2.9 hd/ac, and received PAS or daily SUPL of 0.4% and 0.8% BW cracked corn containing Rumensin. Calves stocked at 2.9 hd/ac had ADG of 1.13, 1.94, and 2.10 lbs/da, respectively, from PAS, 0.4%, and 0.8% BW SUPL. Calves stocked at 2.1 hd/ac had ADG of 2.21, 2.86, and 3.11 lbs/da, respectively, from PAS, 0.4%, and 0.8% BW SUPL. Calves stocked at 1.5 hd/ac had ADG of 2.8, 3.13, and 3.24 lbs/da, respectively, from PAS, 0.4% and 0.8% BW SUPL. Efficiency of SUPL:extra gain was best on HI stocked pastures and least on LO stocked pastures.

Impacts
Long-term, nutrient cycling studies have shown that overseeded cool-season annual clovers can supply adequate N for bermudagrass and at lower costs per pound of gain than overseeded annual ryegrass plus N. Although annual ryegrass plus N produces more dry matter during the summer months, allows for higher stocking rates, and is more resilient to high grazing pressure, economy of production and environmental impact are more favorable with the legume and no-N management system.

Publications

Rouquette, F. M., Jr., K. N. Grigsby, D. K. Hansen, G. D. Potter, and W. C. Ellis. 2005. Effect of SUPL on performance and faecal particle size distribution for yearling horses and weaned calves grazing coastal bermudagrass. XX Intl Grasld. Cong. Dublin, Ireland. Wageningen Academic Publ. The Netherlands. P. 158.
Redmon, L. A., G. M. Clary, J. J. Cleere, G. W. Evers, V. A. Haby, C. R. Long, L. R. Nelson, F.M. Rouquette Jr., and G. R. Smith. 2005. Land Stewardship for the 21st Century: pasture and livestock management workshop for novices. XX Intl Grasld. Cong. Dublin, Ireland. Wageningen Academic Publ. The Netherlands. P. 796.
Haby, V. A., A. T. Leonard, G. M. Clary, F. M. Rouquette Jr., and L. A. Redmon. 2005. Lucerne production and economics on stakeholder ranches on Coastal Plain acid soils. 2005. XX Intl Grasld. Cong. Dublin, Ireland. Wageningen Academic Publ. The Netherlands. P. 848.
Falkenberg, S M., R. K. Miller, J. W. Holloway, F. M. Rouquette Jr., R. D. Randel, and G. E. Carstens. 2005. Ex. Velocity effects on growth, carcass characteristics, and tenderness in half-blood Bonsmara steers. Beef Cattle Res. in Texas. 2005. Texas A&M Univ. Dept. Anim. Sci. pp 105 to 110.
Rouquette, F. M. Jr., J. J. Cleere, C. R. Long, and R. D. Randel. 2005. Birth to Harvest attributes of Brahman and Brahman-influenced steers. Southern Coop-Series Bull Tropically Adapted Breeds-Regional Project S-1013. pp. 38 to 57 (accepted, in press).

Progress 01/01/04 to 12/31/04

Outputs
Primary considerations to optimize biological and economic livestock performance and to sustain pasture productivity are inseparably linked to strategies to enhance forage utilization such as stocking rate, method of stocking, defoliation regimens, forage cultivars, and soil nutrient management. For the past 20 years, a long-term, nutrient management-nutrient cycling experiment has been targeted at documenting soil nutrient status, forage production, forage species composition in pastures, and animal performance from both common (CM) and coastal (CS) bermudagrass pastures. Both CM and CS pastures were overseeded in separate pastures with `Apache' arrowleaf clover (ARL) without nitrogen (N) fertilizer or `TAM-90' annual ryegrass (RYG) plus N fertilizer and all species combinations stocked with cows and calves at three stocking rates (LO, ME, HI) from February through September each year. Expressed as one cow-calf unit (AU) equivalent to 1500 lbs BW, combined steer and heifer calf gains per acre for the 7.5 month grazing period were as follows: 1) CM + ARL at .8 AU/ac (LO) = 463 lbs/ac, at 1.4 AU/ac (ME) = 662 lbs/ac, and at 2.4 AU/ac (HI) = 565 lbs/ac calf gain; 2) CM + RYG at .95 AU/ac (LO) = 591 lbs/ac, at 1.5 AU/ac (ME) = 891 lbs/ac, and at 2.8 AU/ac (HI) = 963 lbs/ac calf gain; 3) CS + ARL at 1.0 AU/ac (LO) = 633 lbs/ac, at 1.6 AU/ac (ME) = 780 lbs/ac, and at 2.7 AU/ac (HI) = 789 lbs/ac calf gain; and 4) CS + RYG at 1.3 AU/ac (LO) = 699 lbs/ac, at 1.9 AU/ac (ME) = 1065 lbs/ac, and at 3.1 AU/ac (HI) = 1149 lbs/ac calf gain. Forage and animal production favored CS pastures overseeded with RYG and N fertilization; however, pasture costs per pound of calf gain favored ARL without N. Winter-born, fall-weaned steers were grazed on `Maton' rye + `TAM-90' annual ryegrass pastures from mid-December to mid-May. Small grain-ryegrass pastures in East Texas have a bimodal DM production characteristic, and the rapid forage growth from March to mid-May often allows for a doubling or tripling of the initial fall stocking rate. In response to this forage DM production, a grazing experiment was initiated to evaluate two stocking rates (LO, one 525 lb steer/ac; and ME, two 525 lb steers/ac) and two stocking strategies (Fixed stocking rate [FIX] which remained constant from initiation to termination, and variable stocking rate [VAR] in which both LO and ME were increased to 3 steers/ac in early March). The two stocking rates and two stocking strategies were stocked continuous (CON) and rotational (RTN) using an 8-paddock, 2- to 3-da residence and 14- to 21-day rest system. Steer ADG was uniform at about 2.7 lbs/da across all LO stocking treatments. However, gain per acre was about 850 lbs/ac from VAR vs. 440 lbs/ac from FIX. At the ME stocked pastures, ADG declined from 2.6 lbs/da on CON to 2.3 lbs/da on RTN. Gain per acre on ME ranged from 835 to 910 lbs/ac for VAR and 675 to 710 for FIX. Management strategies to match forage utilization with forage growth rates during rapid DM production periods in the spring can greatly enhance efficiency of forage utilization, be cost effective, incorporate reduced risk, and be economically rewarding.

Impacts
Long-term, nutrient cycling studies have shown that overseeded cool-season annual clovers can supply adequate N for bermudagrass and at lower costs per pound of gain than overseeded annual ryegrass plus N. Although the annual ryegrass plus N produces more dry matter, allows for higher stocking rates, and is more resilient to high grazing pressure, economy of production and environmental impact are more favorable with the legume and no-N management system.

Publications

Woods, S. A., F. M. Rouquette, Jr., G. E. Carstens, J. L. Kerby, G. H. Nimr, T. D. A. Forbes, and W. C. Ellis. 2004. Performance of stockers grazing Tifton 85 bermudagrass and receiving different levels of protein supplementation. Overton Res. Ctr. Tech. Rept. 2004-1:67-68.
Wright, A. L., F. M. Hons, F. M. Rouquette, Jr. 2004. Long-term management-impacts on carbon and nitrogen dynamics of grazed bermudagrass pasture. Soil Biology and Biochemistry 36:1809-1816.
Aiken, G. E., F. M. Rouquette, Jr., S. F. Tabler, and M. L. Looper. 2004. Prediction of future carcass traits in stocker cattle at the conclusion of grazing. Prof. Anim. Sci. 20:246-254.
Smith, G. R. and F. M. Rouquette, Jr. 2004. Establishment and management of apache arrowleaf clover. Overton Res. Ctr. Tech. Rept. 2004-1:31-32.
Smith, G. R., F. M. Rouquette, Jr., and S. Brown. 2004. Improved cultivars of lablab for Texas. Overton Res. Ctr. Tech. Rept. 2004-1:33-34.
Haby, V. A., A. T. Leonard, and F. M. Rouquette, Jr. 2004. Guidelines for successful alfalfa establishment on acid soils. Overton Res. Ctr. Tech. Rept. 2004-1:47-48.
Rouquette, F. M., Jr., J. L. Kerby, G. H. Nimr, and L. A. Redmon. 2004. Three-year stand survival of selected cool-season perennial grasses in east Texas. Overton Res. Ctr. Tech. Rept. 2004-1:49-50.
Rouquette, F. M., Jr., G. H. Nimr, and J. L. Kerby. 2004. Nutritive value of stockpiled bermuagrass under continuous or strip-stocked management. Overton Res. Ctr. Tech. Rept. 2004-1:59-60.
Rouquette, F. M., Jr., J. L. Kerby, and G. H. Nimr. 2004. Continuous stocked vs strip-stocked stockpiled Coastal bermudagrass during fall-winter. Overton Res. Ctr. Tech. Rept. 2004-1:57-58.

Progress 01/01/03 to 12/31/03

Outputs
Strategies to enhance forage utilization such as stocking rate, method of stocking, defoliation regimens, forage species, and soil nutrient management are primary considerations to optimize biological and economic livestock performance and to sustain pasture productivity. In a long-term nutrient management experiment, common (CM) and Coastal (CS) bermudagrasses were each oversown with `Apache` arrowleaf clover (AR) or `TAM 90` annual ryegrass (RG). These pastures make up the nutrient cycling study involving RG + N fertilizer vs clover, such as AR, without N fertilizer since 1985. Using cows and calves as test animals, calf ADG from February to mid June was not affected by CM or CS bermudagrass. Calf ADG was affected by stocking rate (SR) and ranged from 1.8, 2.9, to 3.6 lbs/da from AR pastures stocked, respectively, at 1.74, 1.25, and 0.75 cow-calf units (1500 lbs) per acre. Calf ADG from RG pastures ranged from 2.5, 3.3, to 3.4, respectively, at SR of 1.74, 1.25, and 0.75 cow-calf units per acre. From mid June through September, all CS supported higher SR than CM pastures, and all RG + N pastures supported higher SR than AR + no N. During the approximate 200-da grazing period, suckling calf total gain per acre was 588, 593, and 420 lbs/ac, respectively, from high (H), medium (M), and low (L) stocked CM + AR; and 865, 727, and 567 lbs/ac, respectively from H, M, and L stocked CS + AR pastures. Total suckling calf gain per acre during the 200-da period for H, M, and L stocked CM + RG was 910, 889, and 548 lbs/ac, respectively; and 1215, 1155, and 713 lbs/ac, respectively, from H, M, and L stocked CS + RG pastures. Total calf gain per acre advantage in favor of RY + N vs. AR + no N for CM was 322, 296, and 128 lbs/ac, respectively, from H, M, and L stocked pastures. The calf gain per acre advantage from N-fertilized vs. no N CS patures was 350, 428, and 146 lbs/ac, respectively, from H, M, and L SR. Thus, at low SR, the clover (AR) with no N fertilizer was likely the most appropriate, economic management practice to implement. Fall-born calves weaned in late June were backgrounded on Tifton 85 bermudagrass until late September. Steers and heifers were allotted to four treatments: 1) Pasture only (PAS); 2) PAS + .2% BW of a 2:1 (Soybean meal:Corn) ration containing Rumensin (.2 SUP); 3) PAS + .4 SUP; and 4) PAS + .8 SUP. Resultant stocker ADG was 1.51, 1.79, 2.02, and 2.44 lbs/da, respectively, from PAS, .2 SUP, .4 SUP, and .8 SUP. Respective stocker gains per acre were 680, 806, 909, and 1098 lbs/ac from these treatments on all pastures which were stocked at five stockers per acre (600 lb = 1 stocker). Conversion of supplement:extra gain was 6.1:1, 6.7:1, and 7.4:1, respectively, for .2 SUP, .4 SUP, and .8 SUP. Except for prolonged dry conditions from mid-August through September, stocker ADG would likely have been higher, and with expected forage mass, SR could have been six to eight 600 lb stockers/ac. Thus, gain per acre potential from Tifton 85 pastures and stockers receiving a protein supplement during a 120 to 150-day period could approach 2000 lbs/ac.

Impacts
Forage-animal performance from different fertility regimens, stocking rates, methods of stocking, backgrounding, and resultant feedlot gains provide the basic structure for economic, environmental, and social decisions to accommodate risk and management of pasture-grazing systems in the humid US.

Publications

Aiken, G. E., F. M. Rouquette, Jr. and R. K. Miller. 2003. Stocking Rate Effects on Ultrasound Measures of 12th to 13th Rib Fat Thickness and Ribeye Area. In 2002 Beef Cattle Research in Texas. Texas A&M University System. College Station, TX . p. 9-12.
Cleere, J. J., A. D. Herring, J. W. Holloway, H. Lippke, C. R. Long, F. M. Rouquette, Jr., B. G. Warrington, K. R. Pond and M. F. Miller. 2003. Winter Pasture Grazing Performance Effects on Feedlot and Carcass Traits in Cattle. In 2002 Beef Cattle Research in Texas. Texas A&M University System. College Station, TX. p. 35-38.
Rouquette, F. M., Jr., J. L. Kerby, G. H. Nimr and W. C. Ellis. 2003. Tifton 85, Coastal Bermudagrass, and Supplement for Backgrounding Fall Born Calves During the Summer. In 2002 Beef Cattle Research in Texas. Texas A&M University System. College Station, TX. p. 62-66.
Strauch, T. A., D. A. Neuendorff, C. G. Brown, C. Cobb, J. L. Kerby, R. D. Randel and F. M. Rouquette, Jr. 2003. Evaluation of the Fibrolytic Enzyme Cattle-Ase on Growth and Puberty of Crossbred Romosinuano and F-1 (Hereford X Brahman) Heifers. In 2002 Beef Cattle Research in Texas. Texas A&M University System. College Station, TX. p.67-70.
Rouquette, F. M., Jr., R. D. Randel, C. R. Long, C. C. Chase, J. C. Paschal and R. K. Miller. 2003. Feedlot Performance and Carcass Traits of Romosinuano Crossbred Steers. In 2002 Beef Cattle Research in Texas. Texas A&M University System. College Station, TX. p. 120-123.
Rouquette, F. M., Jr., C. Chase, R. Randel and C. R. Long. 2003. Performance of Romosinuano-Sired Calves from Angus x Brahman (F-1) Cows from Birth to Yearling.. In 2002 Beef Cattle Research in Texas. Texas A&M University System. College Station, TX. p. 4-7.
Johnson, A. F., D. M. Vietor, F. M. Rouquette, Jr., and V. A. Haby. 2003. Fate of Phosphorus in dairy wastewater and poultry litter applied on grassland. J. Environ. Qual. (In press)
Taliaferro, C., F. M. Rouquette, Jr., and P. Mislevy. 2003. Bermudagrass and Stargrass. ASA Monograph Warm-Season Grasses. (In press)
Smith, G. R., F. M. Rouquette, Jr., and I. J. Pemberton. 2003. Registration of Apache arrowleaf clover. Crop Science. (In press)
Redmon, L. A., G. M. Clary, J. J. Cleere, G. W. Evers, V. A. Haby, C. R. Long, L. R. Nelson, R. D. Randel, F. M. Rouquette, Jr., G. R. Smith and T. L. Thrift. 2003. Ranching for Novices: A New Curriculum for a New Clientele. Journal of Natural Resources and Life Sciences Education. (In press)
Koch, J. W., T. H. Welsh, R. K. Miller, J. O. Sanders, D. G. Riley, D. K. Lunt, J. W. Holloway, T. D. A. Forbes, H. Lippke, F. M. Rouquette, Jr. and R. D. Randel. 2003. Influence of Bos taurus and Bos indicus Breedtype on Production of Cortisol. In 2002 Beef Cattle Research in Texas. Texas A&M University System. College Station, TX. p. 146-148.
Wright, A. L., F. M. Hons, and F. M. Rouquette, Jr. 2003. Long-term accumulation of soil carbon and nitrogen in grazed bermudagrass pastures. In Forage Research in Texas. CPR 5267.

Progress 01/01/02 to 12/31/02

Outputs
Management strategies to enhance forage utilization including stocking rate, method of stocking, defoliation regimens, forage species, and soil nutrient management are primary concerns for biological and economic optimum livestock performance and sustainable pasture systems. In a long-term nutrient management study, Common (CM) and Coastal (CS) bermudagrasses were oversown with ryegrass or clover, Tifton 85 (T85) bermudagrass was oversown with ryegrass, and all pastures grazed at three stocking rates (SR) with cows and calves. Fall-born suckling calf performance from March to early June at SR of about 0.8, 1.35, and 1.8 cow-calf units (1500 lbs) per acre was about 2.0, 2.75, and 3.15 lbs/da, respectively. Winter-born suckling calf ADG from mid-June to late September for high, medium, and low SR was about 1.1, 2.1, and 2.2 lbs/da, respectively, for CM; 1.1, 2.2, and 2.75 lbs/da, respectively, for CS; and 2.4, 2.8, and 3.2 lbs/da, respectively, for T85. The enhanced digestibility of ADF components of T85 allowed for increased calf ADG during the summer months. Corresponding SR for these calf ADG were about 3.0, 1.75, and 1.0 cow-calf units/ac, respectively. Fall-born, early summer weaned calves grazed CS and T85 with and without a 2 lb per hd per day 28 percent protein supplement (SUP) during July, August, and September. Resultant ADG for steers and heifers was 1.01, 1.30, 1.69, and 2.02 lbs/da, respectively, for CS, CS plus SUP, T85, and T85 plus SUP. The ADG of F-1 Hereford x Brahman steers was increased by about 0.7 lb/da on these same treatments with respective ADG of 1.64, 2.04, 2.33, and 2.89 lbs/da. Although there was an approximate 0.3 lb/da gain due to supplementation, the supplement:extra gain ratio was about 6:1 which was less efficient than anticipated. The increased nutritive value of T85 bermudagrass offers additional opportunities for management for backgrounding steers or replacement heifers. Fall-born, summer weaned heifers were backgrounded on CS hay with and without SUP and with and without a fibrolytic enzyme, Cattle-ASE. During the first 126 days, heifers receiving the fibrolytic enzyme had higher ADG and a higher percent that reached puberty. Winter-born calves weaned in late September were grazed on rye-ryegrass pastures at different SR from January to mid-May and then transported to Lubbock, TX for feedlot finishing to assess the effect of pasture gains on subsequent feedlot performance and carcass traits. Feedlot performance was affected by previous pasture growth rate of steers when stocked at medium and high SR. There were no compensating gains from steers grazed at low SR. Since steers were finished to a common end-point of about 0.4 inch backfat, the only differences in carcass traits were hot carcass weight and total carcass value. In addition, steers on high SR had smaller ribeye area of carcass. Thus management strategies to optimize or maximize pasture ADG were most beneficial biologically and economically when considering lifetime performance of livestock.

Impacts
Forage-animal performance from different fertility regimens, stocking rates, methods of stocking, backgrounding, and resultant feedlot gains provide the basic structure for economic, environmental, and social decisions to accommodate risk and management of pasture-grazing systems in the humid US.

Publications

Strauch, T. S., D. A. Neuendorff, C. G. Brown, C. Cobb, J. L. Kerby, R. D. Randel, and F. M. Rouquette, Jr. 2002. Effects of the fibrolytic enzyme Cattle-AseT on growth of prepuberal Romosinuano crossbred heifers. Overton Res. Ctr. Tech. Rept. 2002-1:97-98.
Clary, Greg, Kelli Norman, Jim McGrann, F. M. Rouquette, Jr. 2002. Texas beef industry database (BEEFSYS). Overton Res. Ctr. Tech. Rept. 2002-1:123-124.
Smith, G. R., F. M. Rouquette, Jr., and I. J. Pemberton. 2002. Apache arrowleaf clover. Overton Res. Ctr. Tech. Rept. 2002-1:23-24.
Smith, G. R., I. J. Pemberton, F. M. Rouquette, Jr., and G. W. Evers. 2002. Forage production of Apache arrowleaf clover. Overton Res. Ctr. Tech. Rept. 2002-1:25-26.
Haby, V. A., F. M. Rouquette, Jr., and A. T. Leonard. 2002. Requirements for successful alfalfa establishment on acid soils. Overton Res. Ctr. Tech. Rept. 2002-1:31-32.
Rouquette, F. M., Jr., J. Kerby, G. Nimr, and V. Haby. 2002. Persistence of alfalfa varieties under three stocking methods on coastal plains soils in east Texas. Overton Res. Ctr. Tech. Rept. 2002-1:33-34.
Redmon, L. A., J. L. Kerby, G. H. Nimr, and F. M. Rouquette, Jr. 2002. Persistence of cool-season perennial grasses in east Texas. Overton Res. Ctr. Tech. Rept. 2002-1:39-40.
Cleere, J. J., F. M. Rouquette, Jr., A. D. Herring, and C. R. Long. 2002. Effect of rye-ryegrass stocking rate, breed types, and sex of calf on feedlot performance. Overton Res. Ctr. Tech. Rept. 2002-1:73-74.
Cleere, J. J., F. M. Rouquette, Jr., A. D. Herring, and C. R. Long. 2002. Effect of pasture stocking rate, breed types, sex of calf and feedlot performance on carcass traits. Overton Res. Ctr. Tech. Rept. 2002-1:75-76.
Cleere, J. J., F. M. Rouquette, Jr., A. D. Herring, H. Lippke, B. G. Warrington, J. W. Holloway, and C. R. Long. 2002. Effect of previous stocking rate of rye-ryegrass pasture and four breed types of calves on feedlot performance. Overton Res. Ctr. Tech. Rept. 2002-1:77-78.
Cleere, J. J., F. M. Rouquette, Jr., A. D. Herring, H. Lippke, B. G. Warrington, J. W. Holloway, and C. R. Long. 2002. Previous stocking rate on winter pasture, four breed types, and feedlot performance on carcass traits. Overton Res. Ctr. Tech. Rept. 2002-1:79-80.
Rouquette, F. M., Jr., J. Kerby, G. Nimr, and G. Smith. 2002. Cow-calf performance from Common, Coastal, and Tifton 85 bermudagrass when grazed at three stocking rates. Overton Res. Ctr. Tech. Rept. 2002-1:81-82.
Rouquette, F. M., Jr., J. Kerby, and G. Nimr. 2002. Backgrounding stocker calves post-weaning on Tifton 85 bermudagrass alone or Coastal bermudagrass plus supplementation. Overton Res. Ctr. Tech. Rept. 2002-1:83-84.
Rouquette, F. M., Jr., J. Kerby, G. Nimr, J. Sanders, and D. Lunt. 2002. Continuous 8-paddock, and 16-paddock grazing at two stocking rates with different breed types. Overton Res. Ctr. Tech. Rept. 2002-1:85-86.
Rouquette, F. M., Jr., J. Kerby, G. Nimr, H. Lippke, B. Warrington, B. Holloway, J. Sanders, and D. Lunt. 2002. Influence of environment, pre-feedlot growth rate, and breed types on feedlot performance. Overton Res. Ctr. Tech Rept. 2002-1:87-88.
Rouquette, F. M., Jr., J. Kerby, G. Nimr, H. Lippke, B. Warrington, B. Holloway, J. Sanders, D. Lunt, and R. Miller. 2002. Carcass trait effects from environment, growth rate on pasture, and breedtypes. Overton Res. Ctr. Tech. Rept. 2002-1:89-90.
Rouquette, F. M., Jr., J. Kerby, G. Nimr, C. Chase, R. Randel, and C. R. Long. 2002. Birth weights, weaning weights, and average daily gain of Romosinuano-sired calves from first and second calving Angus x Brahman (F-1) cows. Overton Res. Ctr. Tech. Rept. 2002-1:91-92.
Rouquette, F. M., Jr., J. Kerby, G. Nimr, C. Cobb, D. A. Neuendorff, R. Randel, and T. A. Strauch. 2002. Stocker performance of Romosinuano crossbred steers grazing bermudagrass and receiving a supplement. Overton Res. Ctr. Tech. Rept. 2002-1:93-94.
Redmon, L. R., F. M. Rouquette, Jr., and M. J. Florence. 2002. Use of mefluidide to alter growth and nutritive value of pearl millet. J. Plant Nutrition (in press).
Aiken, G. E., F. M. Rouquette, Jr., and R. K. Miller. 2002. Grazing treatment effects on ultrasound measures of carcass-related traits. The Prof. Anim. Sci. 18:368-372.
Huston, J. R., F. M. Rouquette, Jr., W. C. Ellis, H. Lippke, and T. D. A. Forbes. 2002. Supplementation of Grazing Beef Cattle. Technical Monograph 12. Texas Agric. Exp. Sta. Texas A&M Univ. College Sta., TX 94pp.

Progress 01/01/01 to 12/31/01

Outputs
Forage utilization strategies, which include stocking rate, method of grazing, defoliation regimens, forage species, and soil nutrient management, are important management concerns for biological and economic optimum livestock performance and sustainable pasture systems. Common (CM) and Coastal (CS) bermudagrass have been grazed at 3 stocking rates (SR) at TAMU-Overton from 1969 to date with cows and calves. All pastures were identically fertilized through the summer-fall of 1984. In the autumn of 1984, all pastures were divided into 2 pastures to meet objectives for a nitrogen (N) vs no-N nutrient cycling experiment. The N pastures were sod-seeded with `TAM-90' annual ryegrass (RYG); whereas the no-N pastures were overseeded with a mixture of `Tibbee' crimson clover and `Apache' arrowleaf clover (CLV). At the high SR (2 pair/ac), calf ADG was highest on RYG pastures compared to CLV pastures (1.9 vs 1.5 lbs/da). At the medium SR (1.25 pair/ac), calf ADG ranged from 2.25 to 2.75 lbs/da and was affected by bermudagrass. At the low SR (0.75 pair/ac), calf ADG was about 3.15 lbs/da and tended to be slightly higher for CLV pastures. Winter-born calves weaned in the autumn were grazed on `Maton' rye + TAM-90 ryegrass from January to Mid-May at 2 stocking rates to achieve different growth rates on pasture for subsequent feedlot-carcass experiments. Three breed types, 100% Brahman (BRM), 50% Brahman (.5BR), and 25% Brahman (.25BR) were grazed at different stocking rates. Across grazing methods, ADG at the high SR were 1.4 lb/da (BRM), 1.0 lb/da (.5BR), and 1.6 lb/da (.25BR); whereas at the low SR, ADG were 2.0 lb/da (BRM), 2.2 lb/da (.5BR), and 2.8 lb/da (.25BR). In the feedlot phase there was no clear trend for compensating gain, thus, cattle that had high ADG on pasture continued to gain as good or better than pasture cattle with low ADG. Days on feed was less for low SR pasture cattle to reach targeted 0.4 inch backfat. Real-time ultrasound scans were made at the initiation and termination of the winter pasture grazing phase to ascertain the effects of liveweight gain on pasture to backfat and ribeye area. Both fat and ribeye area accretions followed similar trends as liveweight gains due to SR. Accretion of fat over the ribeye relative to the expansion of the ribeye area declined linearly with increased SR. The final fat relative to the final ribeye area showed a curvilinear decline with increased SR. Fall-born calves weaned in June were grazed on either `Tifton-85' (T-85) bermudagrass without supplementation or CS with 2 lbs/da of a 1:1 (Corn : Soybean Meal) supplement. During a 75-day summer grazing-feedlot backgrounding period, ADG was similar for both treatment groups at 1.45 lbs/da. Thus, the higher nutritive value of T-85 provided for the same stocker ADG as CS plus supplementation. The use of T-85 for summer stocker grazing appears to have positive implications on expanded retained ownership or commercial summer stocker operations in the southeastern USA.

Impacts
Forage and animal performance data from different fertility regimens and stocking rates provide the basic structure for economic, environmental, and social decisions for risk aversion and management of pasture systems in the humid southeastern US.

Publications

F. M. Rouquette, Jr., V.A. Haby, J. O. Fritz, and M. Collins. 2001. Boron fertilization effects on nutritive parameters of alfalfa. Proc. Int'l. Grasld. Cong. Brazil XIX:382-384.
G. R. Smith and F. M. Rouquette, Jr. 2001. Improvement of rose clover winter forage production. Proc. Int'l. Grasld. Cong. Brazil XIX:566-567.
Aiken, G. E., F. M. Rouquette, Jr. and A. H. Brown, Jr. 2001. Sources of error for ultrasound measurements of steer compositional traits in grazing studies. Proc. Int'l Grasld. Cong. Brazil XIX:1043-1044.

Progress 01/01/00 to 12/31/00

Outputs
Primary management concerns for optimum livestock performance and sustainable forage-pasture systems include forage utilization strategies, method of grazing, stocking rate, defoliation regimens, and forage species. Common (COM) and Coastal (CST) bermudagrass pastures used in long-term nutrient cycling experiments at TAMU Overton were overseeded with either 'Tibbee' crimson clover (CLV), or 'TAM 90' ryegrass (RYG). During two consecutive years, winter-born Angus x Brahman (F-1) heifers were fall-weaned, backgrounded on hay and supplement, and initiated full-time continuous grazing of CLV and RYG in early February. Both CLV and RYG pastures were stocked at 3 rates. Pastures stocked from 1.5 to 4 heifers/ac produced 2-year ADG of 3.4 to 1.05 lbs/da. Liveweight gain per acre across stocking rates was 430 to 820 lbs/ac in year 1 and 454 to 920 lbs/ac in year 2. The 2-year data showed greater ADG from overseeded CST (2.35 lbs/da), compared to overseeded COM (2.11 lbs/da). There was also a slight (P=.08) advantage in ADG for heifers grazing RYG (2.28 lbs/da), compared to heifers grazing CLV (2.18 lbs/da). Stocking rate (SR) affected (P=.001) ADG in both years and averaged 2.81 lbs/da for low SR, 2.44 lbs/da for medium SR, and 1.45 lbs/da for high SR. Body condition scores (BCS) of heifers grazing RYG were greater (fatter) than heifers grazing CLV (6.45 vs 6.10). The BCS were affected most by SR and ranged from 5.6, 6.4, to 6.9 respectively, for high, medium, and low SR. Replacement heifers which weighed 500 to 550 lbs at initiation of grazing RYG or CLV pastures can make excellent ADG and reach appropriate weights for breeding without protein or energy supplementation. Pasture costs per lb heifer gain ranged from about $.10 to $.25/lb and was stocking rate dependent. In another 2-year grazing experiment, 'Maton' rye and RYG pastures were stocked with 600-lb (initial weight) steers, from early December to mid-May. Steers grazed on either continuously stocked (CONT), or rotationally stocked (ROTN) pastures, each at three SR. The ROTN treatment was an 8 paddock system with a 2- to 3-day residence time. Initial SR were 1.6, 2.2, and 2.8 steers/ac, respectively, for low, medium, and high. The 2-year ADG was similar for CONT (2.95 lbs/da) and ROTN (2.91 lbs/da). The ADG of steers on ROTN was improved over steers on CONT pastures for both medium (2.37 vs 2.12 lbs/da), and high SR (1.35 vs 0.96 lbs/da). The 2-year gains per acre were about 740 lbs/ac for low SR CONT, low SR ROTN, and medium SR CONT. Medium SR ROTN had 824 lbs/ac, high SR ROTN had 604 lbs/ac, and high SR CONT had 435 lbs/ac gain. The impact of method of grazing was evident at higher stocking rates with the period of deferment on ROTN pastures which allowed for more forage dry matter production. Costs per pound of gain for the 2-year period were affected by year and method of grazing and ranged from about $.15 to $.20 on all low and medium SR, and $.17 to $.90 for high SR.

Impacts
Forage and animal performance data from different fertility regimens and stocking rates provide the basic structure for economic, environmental, and social decisions for risk aversion and management of pasture systems in the humid southeastern US.

Publications

Rouquette, F. M., Jr., J. L. Kerby, G. H. Nimr, and G. M. Clary. 2000. Final stocker weights and economic summary of rye-ryegrass pastures as influenced by grazing method and stocking rate. Overton Res. Ctr. Tech. Rept. 2000-1:99-100.
Clary, G. M. and F. M. Rouquette, Jr. 2000. Economic assessment of steers pastured at three stocking rates under a continuous grazing system. Overton Res. Ctr. Tech. Rept. 2000-1:101-102.
Clary, G. M. and F. M. Rouquette, Jr. 2000. Economic assessment of steers pastures at three stocking rates under a rotational grazing system. Overton Res. Ctr. Tech. Rept. 2000-1:103-104.
Rouquette, F. M., Jr., A. T. Leonard, and V. A. Haby. 2000. Nutritive value of alfalfa leaf and stem as affected by harvest date and boron rate. Overton Res. Ctr. Tech. Rept. 2000-1:37-38.
Rouquette, F. M., Jr., A. T. Leonard, and V. A. Haby. 2000. Nutritive value and relative feed value of 'Alfagraze' alfalfa during the summer hay harvest period. Overton Res. Ctr. Tech. Rept. 2000-1:39-40.
Redmon, L. A., J. L. Kerby, G. H. Nimr, and F. M. Rouquette, Jr. 2000. Cool-season perennial forage grasses for cow-calf and stocker production in East Texas. Overton Res. Ctr. Tech. Rept. 2000-1:41-42.
Najjar, N. F., F. M. Rouquette, Jr., D. M. Vietor, V. A. Haby, G. W. Evers, J. Muir, R. Jones, and M. J. McFarland. 2000. Nonpoint source phosphorus from grazinglands. Overton Res. Ctr. Tech. Rept. 2000-1:89-90.
Haby, V. A., A. T. Leonard, F. M. Rouquette, Jr., G. M. Clary, and L. A. Redmon. 2000. On-farm alfalfa establishment demonstrations in the Southern Region Sustainable Agriculture Research and Education Program. Overton Res. Ctr. Tech. Rept. 2000-1:95-96.
Rouquette, F. M., Jr. and G. M. Clary. 2000. Pasture costs for cows and calves grazing ryegrass + nitrogen or clover + potassium. Overton Res. Ctr. Tech. Rept. 2000-1:97-98.
Aiken, G. E., and F. M. Rouquette, Jr. 2000. Potential of real-time ultrasound technology as a research tool in grazing experiments. In Proc. Am. Forage and Grasl. Conf. Madison, WI. AFGC. Georgetown, TX.
Haby, V. A., A. T. Leonard, and F. M. Rouquette, Jr. 2000. Alfalfa production on Coastal Plain soils. In Proc. Am. Forage Grasl. Conf. Madison, WI. AFGC. Georgetown, TX.
Rouquette, F. M., Jr., J. L. Kerby, G. H. Nimr, V. A. Haby, and G. R. Smith. 2000. Stocking rate and overseeded bermudagrass pasture effects on Angus x Brahman (F-1) heifer performance. Overton Res. Ctr. Tech. Rept. 2000-1:13-14.
Rouquette, F. M., Jr., J. L. Kerby, G. H. Nimr, and D. P. Hutcheson. 2000. Evaluation of Cattle-AseT on gain of yearling heifers grazing bermudagrass. Overton Res. Ctr. Tech. Rept. 2000-1:15-16.
Rouquette, F. M., Jr., J. L. Kerby, and G. H. Nimr. 2000. Steer performance affected by grazing method and stocking rate. Overton Res. Ctr. Tech. Rept. 2000-1:17-18.
Rouquette, F. M., Jr., J. L. Kerby, and G. H. Nimr. 2000. Feedlot performance of steers and heifers grazed at three stocking rates on rye-ryegrass pastures. Overton Res. Ctr. Tech. Rept. 2000-1:19-20.
Aiken, G. W., S. F. Tabler, J. L. Kerby, G. H. Nimr, and F. M. Rouquette, Jr. 2000. Ultrasonic measures of backfat depth and ribeye area for steers grazing rye-ryegrass at three stocking rates. Overton Res. Ctr. Tech. Rept. 2000-1:21-22.
Rouquette, F. M., Jr., J. L. Kerby, and G. H. Nimr. 2000. Carcass characteristics of steers and heifers previously grazed at three stocking rates and feedlot finished. Overton Res. Ctr. Tech. Rept. 2000-1:23-24.
Koch, J. W., T. H. Welsh, R. K. Miller, J. O. Sanders, D. G. Riley, D. K. Lunt, J. W. Holloway, T.D.A. Forbes, H. Lippke, F. M. Rouquette, Jr., and R. D. Randel. 2001. Influence of Bos taurus and Bos indicus breedtype on production of cortisol. Overton Res. Ctr. Tech. Rept. 2000-1:25-26.
Smith, G. R. and F. M. Rouquette, Jr. 2000. Improvement of rose clover winter forage production. Overton Res. Ctr. Tech. Rept. 2000-1:31-32.
Clary, G. M. and F. M. Rouquette, Jr. 2000. Economic assessment of feedlot and overall stocker-feedlot performance for steers and heifers, 1998-99. Overton Res. Ctr. Tech. Rept. 2000-1:105-106.

Progress 01/01/99 to 12/31/99

Outputs
Forage utilization strategies, method of grazing, stocking rate, defoliation regimens, and forage species are important management concerns for optimum livestock performance and sustainable pasture systems. Common and Coastal bermudagrass pastures have been grazed at 3 stocking rates at TAMU-Overton from 1969 to date with cows and calves. From 1969 through 1984, annual fertilization was 200-100-100 lbs/ac of N-P2O5-K2O and pastures were overseeded with annual ryegrass and various clovers (crimson, arrowleaf, subterranean, ball, red, white). From 1985 to 1997, each bermudagrass stocking rate pasture was divided into two overseeding x fertilizer treatments: (1) ryegrass + N only, and (2) clover + K only. From 1990-1997, N applications (250 lbs N/ac per year) were made only during the ryegrass growing period with no N applied to exclusive bermudagrass. Two cow-calf herds were used to assess animal performance at different stocking rates (fall calvers from February to June; winter calvers from June to September). The objective of this experiment was to quantify pasture-animal performance from various stocking rate x fertility regimens. Even though bermudagrass did not receive N during the summer months, stocking rates on exclusive bermudagrass ranged from about 0.70 to 3.4 cow-calf units (approx. 1500 lbs/cow-calf unit) per acre, suckling calf ADG ranged from less than 1.0 lb/day on high stocked to nearly 2.5 lbs/day on low stocked pastures, and bermudagrass pasture productivity ranged from 100 to 360 lbs/ac calf weight from mid-June to September. Total seasonal gains per acre were generally higher on high or medium stocked pastures (550 to 700 lbs) compared to low stocking rates (300 to 500 lbs). On both common and Coastal bermudagrass pastures, gain per acre was optimum-maximum on high (2.0 AU/ac) or medium (1.2 AU/ac) stocked pastures that had been overseeded with ryegrass and N fertilization. At lower stocking rates (.8 AU/ac), however, differences in gain per acre between N vs non-N fertilization were not as great. But, the residual forage that remained (risk factor) on low stocked Coastal bermudagrass pastures was 2 to 4-fold that on common bermudagrass pastures. Bermudagrasses on sandy soils are efficient in utilizing plant food nutrients from existing or previously applied sources. In humid environments, year-long bermudagrass pastures may be productive, sustainable, and vigorous during prolonged periods (years) of non-N fertilization.

Impacts
Forage and animal performance data from different fertility regimens and stocking rates provide the basic structure for economic, environmental, and social decisions for risk aversion and management of pasture systems in the humid southeastern US.

Publications

Ellis, W. C., Poppi, D. P., Matis, J. H., Hill, T. M., and Rouquette, F. M., Jr. 1999. Dietary-digestive-metabolic interactions determining the nutritive potential of ruminant diets. Jung, H. G. and G. C. Fahey, Jr. (eds.) p. 423-481. IN Nutritional Ecology of Herbivores, Proc. V Int'l. Symp. on the Nutrition of Herbivores. Anim. Sci. Soc., Savoy, IL.
Holloway, J. W., Warrington, B. G., Randel, R. D., Rouquette, F. M., Jr., and Long, C. R. 1998. Tropically adapted beef cattle: preweaning performance on South Texas rangeland. Uvalde Research and Extension Center. Bottom Lines-L3.
Holloway, J. W., Warrington, B. G., Randel, R. D., Rouquette, F. M., Jr., and Long, C. R. 1998. Tropically adapted beef cattle: Postweaning heifer development on South Texas rangeland. Uvalde Research and Extension Center. Bottom Lines-L4.
Holloway, J. W., Warrington, B. G., Randel, R. D., Rouquette, F. M., Jr., and Long, C. R. 1998. Tropically adapted beef cattle: Reproduction of first-calf females on South Texas rangeland. Uvalde Research and Extension Center. Bottom Lines-L7.
Holloway, J. W., Warrington, B. G., Rouquette, F. M., Jr., and Long, C. R. 1998. Tropically adapted beef cattle: Brood female performance on South Texas rangeland. Uvalde Research and Extension Center. Bottom Lines-L8.
Holloway, J. W., Warrington, B. G., Forrest, D. W., Owens, M. K., Rouquette, F. M., Jr., and Long, C. R. 1998. Late maturing females have greater fertility on rangeland...sometimes. Uvalde Research and Extension Center. Bottom Lines-L16.
Forbes, T.D.A., Rouquette, F. M., Jr., and Holloway, J. W. 1998. Tuli-sired heifers have similar intakes and heat adaptation as Brahman crossbred heifers. Uvalde Research and Extension Center. Bottom Lines-L19.
Steward, W. M., Haby, V. A., Rouquette, F. M., Jr., and Redmon, L. A. 1999. Make balanced fertility a priority this summer. News and Views. Potash & Phosphate Institute.
Brockett, J. R., Rouquette, F. M., Jr., Turner, J. W., Coleman, S. W., and Miller, R. K. 1999. Tropical sire breed comparisons for birth to slaughter growth, carcass composition, and sensory characteristics as influenced by stocker environment. J. Anim. Sci. 77(Suppl. 1):4.
Rouquette, F. M., Jr., and Thurow, T. L. 1999. Soil compaction of bermudagrass pastures grazed for 25 years at different stocking rates. Southern Branch ASA Abstracts. No. 26, p. 9.
Rouquette, F. M., Jr., Smith, G. R., and Haby, V. A. 1999. Soil nutrient status in bermudagrass pastures under long-term stocking rates and fertility regimens. Agron. Abstr. p. 143.

Progress 01/01/98 to 12/31/98

Outputs
Forage utilization strategies, method of grazing, stocking rate, defoliation regimens, and forage species are important management concerns for optimum livestock performance and sustainable pasture systems. Common and Coastal bermudagrass (Cynodon dactylon L.) pastures have been stocked at three different levels since 1969 as a component of nutrient cycling, forage sustainability, and livestock production experiments. During the past 14-years, fertility treatments on each of the 3 stocking rates of both forages have included N + ryegrass (RYG) vs K + clover (CLV). Soil pH, nitrate-N, P and K have been monitored periodically (3-5-year periods) at multiple soil depths. The RYG pastures have required lime applications at 2- to 3-year intervals with an average of 800 lbs/ac per year; whereas, the CLV pastures were treated with a total of 3 tons/ac within the first two years of study initiation, and have had no additional lime in the past 11 years. The pH of CLV pastures has remained at 6.1 to 6.5. The pH of RYG pastures was lower (P<.01) at each of soil depths 0-6", 6-18", and 18-36". From 36" to 60", pH was similar among treatments. Soil pH was higher (P<.01) on high stocked (HI) compared to low stocked (LO) pastures at every soil depth. Soil nitrate-N levels were higher (P<.01) for RYG compared to CLV pastures at every sampling depth. There was no effect of stocking rate on soil nitrate-N. On these sandy soils, soil nitrate-N was moderately stable from 18-60" at about 5 ppm. Although no P fertilizer had been applied for 14 years, soil P was greater (P<.01) in RYG pastures compared to CLV at every depth from 0 to 36", and was not different between treatments at deeper sites. The HI pastures (2-3 animal units/ac) had higher (P<.01) soil P at every depth from 0-60" than the LO (1 AU/ac) or medium stocked (MED) (1.5 AU/ac) pastures. From 1985 to 1998 (no fertilizer P applied), soil P in the 0-6" soil depth remained unchanged and diminished only slightly in the 6-18" depth. Soil K differences between RYG and CLV pastures were relatively predictable in the 0-6" and 6-18" soil depths with the K-applied pasture soils (CLV) having the most (P<.01) K present. However, in the 18-60" depths. There was no difference in soil K between pastures that had received annual rates of 100 lbs K2O/ac and pastures that had not received fertilizer K2O for 13 years. There was no clear trend to effect of stocking rate on soil K. This East Texas long-term, exclusive grazing experiment documents the impact of nutrient cycling on the stability of nutrients in sandy soils.

Impacts
(N/A)

Publications

Rouquette, F. M., Jr., Kerby, J. L., Nimr, G. H., Pemberton, I. J., Smith, G. R., and Haby, V. A. 1998. Soil potassium in bermudagrass pastures under long-term stocking rates and fertility regimens. Overton Research Center Tech. Rep. 98-1:29-30.
Pemberton, I. J., Smith, G. R., Philley, G. L., and Rouquette, F. M., Jr. 1998. First report of four new diseases on arrowleaf clover in East Texas. Overton Research Center Tech. Rep. 98-1:35-36.
Rouquette, F. M., Jr., Kerby, J. L., and Nimr, G. H. 1998. Pasture and animal performance from bermudagrass pastures at three stocking rates with or without nitrogen fertilization. Overton Research Center Tech. Rep. 98-1:65-66.
Rouquette, F. M., Jr., Thurow, T. L., Kerby, J. L., and Nimr, G. H. 1998. Soil compaction of bermudagrass pastures grazed at three stocking rates for 25 years. Overton Research Center Tech. Rep. 98-1:67-68.
Rouquette, F. M., Jr., Kerby, J. L., Nimr, G. H, Warrington, B. G., and Holloway, J. W. 1998. Continuous vs rotational grazing of rye-ryegrass pastures at three stocking rates. Overton Research Center Tech. Rep. 98-1:69-70.
Smith, G. R., and Rouquette, F. M., Jr. 1998. Cattle grazing acceptance of summer forage legumes. Overton Research Center Tech. Rep. 98-1:71-72.
Rouquette, F. M., Jr., Long, C. R., Warrington, B. G., and Holloway, J. W. 1998. Feedlot performance of steers and heifers previously pastured at three stocking rates. Overton Research Center Tech. Rep. 98-1:103-104.
Rouquette, F. M., Jr., Long, C. R., Warrington, B. G., and Holloway, J. W. 1998. Carcass traits of steers and heifers previously pastured at three stocking rates. Overton Research Center Tech. Rep. 98-1:105-106.
Rouquette, F. M., Jr., and Clary, G. M. 1998. Pasture costs associated with grazing bermudagrass-rye-ryegrass with stocker cattle. Overton Research Center Tech. Rep. 98-1:111-112.
Clary, G. M., and Rouquette, F. M., Jr. 1998. Economic assessment of Simmental-sired steers and heifers from pasture to packer. Overton Research Center Tech. Rep. 98-1:113-114.
Clary, G. M., Rouquette, F. M., Jr., Warrington, B. G., and Holloway, J. W. 1998. Economic assessment of Angus and Limousin-sired steers and heifers from pasture to packer. Overton Research Center Tech. Rep. 98-1:115-116.
Forbes, T.D.A., Rouquette, F. M., Jr., and Holloway, J. W. 1998. Comparisons among Tuli-, Brahman-, and Angus-sired heifers: Intake, digesta kinetics, and grazing behavior. J. Anim. Sci. 76:220-227.
Pemberton, I. J., Smith, G. R., Philley, G. L., Rouquette, F. M., Jr., and Yuen, G. Y. 1998. First report of Pythium ultimum, P. irregulare, Rhizoctonia solani AG4 and Fusarium proliferatum from arrowleaf clover: A disease complex. Plant Disease 82:128.
Stout, S. A., Haby, V. A., Hons, F. M., and Rouquette, F. M., Jr. 1998. Treatment and seasonal effects on alfalfa crude protein content. Overton Research Center Tech. Rep. 98-1:11-12.
Rouquette, F. M., Jr., Kerby, J. L., Nimr, G. H., Pemberton, I. J., Smith, G. R., and Haby, V. A. 1998. Soil nitrate levels in bermudagrass pastures under long-term stocking rates and fertility regimens. Overton Research Center Tech. Rep. 98-1:23-24.
Rouquette, F. M., Jr., Kerby, J. L., Nimr, G. H., Pemberton, I. J., Smith, G. R., and Haby, V. A. 1998. Soil pH of bermudagrass pastures under long-term stocking rates and fertility regimens. Overton Research Center Tech. Rep. 98-1:25-26.
Rouquette, F. M., Jr., Kerby, J. L., Nimr, G. H., Pemberton, I. J., Smith, G. R., and Haby, V. A. 1998. Soil phosphorus in bermudagrass pastures under long-term stocking rates and fertility regimens. Overton Research Center Tech. Rep. 98-1:27-28.

Progress 01/01/97 to 12/31/97

Outputs
Forage utilization strategies, method of grazing, stocking rate, defoliation regimens, and forage species are important management concerns for optimum livestock performance and sustainable pasture systems. Common and 'Coastal' bermudagrass (Cynodon dactylon L.) pastures have been stocked at three different levels since 1969 as a component of nutrient cycling, forage sustainability, and livestock production experiments. During the past 13 years, fertility treatments on each of the 3 stocking rates of both forages have included N vs no N. The N plus ryegrass overseeded treatments provided for an average of 202 days grazing; whereas, the K plus clover overseeded treatments provided for 179 days grazing. Coastal bermudagrass supported higher stocking rates (.9 to 3.2 1500-lb animal-units (AU)/ac) than common bermudagrass (.8 to 2.1 AU/ac). Bermudagrass, fertilizer, stocking rate, and bermudagrass x stocking rate were significant (P<.01) factors affecting the percent live components of bermudagrass. The amount of senesced plant parts and/or thatch (dead) was affected by stocking rate and interactions of stocking rate with bermudagrass and fertility (P<.01). Stand density as indicated by percent soil not covered by forage or thatch was influenced by N, stocking rate, and N x stocking rate (P<.01). The most detrimental impact of sward components on both bermudagrass species occurred from high stocking in which no N was used. The relatively high percent soil (18.3%) and invading species such as bahiagrass (Paspalum notatum Flugge) were about 4% on high-stocked common bermudagrass which indicated stand deterioration and/or changes in plant ecological components. Paspalum infestations have been greater in common vs Coastal bermudagrass, and greater in no N vs N-treated pastures. Bermudagrass, because of its deep rooting characteristics and relatively high biomass production, is an efficient forage in the processes of recycling plant food nutrients under grazing conditions. 'Alfagraze' alfalfa was sodseeded into Coastal bermudagrass at 3 drill widths (10, 20, and 30 in.) and rotationally grazed to ascertain plant vigor and stand maintenance of alfalfa and bermudagrass. During year 1, an excellent stand of alfalfa existed at all three drill widths; however, at the end of year 2, alfalfa was not sufficiently abundant to be recognized as a stand. Final stand rating (harvest and separation) revealed the alfalfa:bermudagrass ratio on areas drilled at 10, 20, and 30 in., respectively, were 14:86, 11:89, and 5:95. Conclusions reached were that: (1) Coastal bermudagrass was too competitive to be used as a companion crop for grazing; (2) alfalfa stand survival was more dependable under hay harvest regimens than under grazing; and (3) the rest-graze rotation schedules used in this study were not compatible with stand survival. The use of alfalfa in sandy, acid, low fertility soils of East Texas requires significantly more monetary and management input than other forages currently being used.

Impacts
(N/A)

Publications

ROUQUETTE, F. M., JR., CHANDLER, D. T., RANDEL, R. D., LONG, C. R., WELSH, T. H., JR., WARRINGTON, B. G., and HOLLOWAY, J. W. 1997. Mexican steer phenotype and performance: Grazing humid pastures or semi-arid range. p. 143-146. In Proc. Am. Forage Grassl. Conf. Ft. Worth, TX. Am. Forage Grassl. Council, Georgetown, TX.
ROUQUETTE, F. M., JR., CHANDLER, D. T., RANDEL, R. D., LONG, C. R., WELSH, T. H., JR., WARRINGTON, B. G., and HOLLOWAY, J. W. 1997. Mexican steer phenotype and performance: Feedlot and carcass traits of cattle backgrounded in two environments. p. 188-192. In Proc. Am. Forage Grassl. Conf. Ft. Worth, TX. Am. Forage Grassl. Council. Georgetown, TX.
ROUQUETTE, F. M., JR., SMITH, G. R., and HABY, V. A. 1997. Bermudagrass pastures under long-term stocking rates and fertility regimens. p. 73-74. In Proc. XVIII International Grassl. Cong. Session 22. Saskatoon, Saskatchewan, Canada.
REDMON, L. A., ROUQUETTE, F. M., JR., SMITH, G. R., FLORENCE, M. J., and STUTH, J. W. 1997. Interseeded legumes with loblolly pine. I. Effect of phosphorus and legume variety on pine seedling establishment and mortality. J. Plant Nutr. 20:1755-1764.
REDMON, L. A., ROUQUETTE, F. M., JR., SMITH, G. R., FLORENCE, M. J., and STUTH, J. W. 1997. Interseeded legumes with loblolly pine. II. Effect of phosphorus and legume variety on the growth of pine seedlings. J. Plant Nutr. 20:1765-1772.
ROUQUETTE, F. M., JR., BRANSBY, D. I., and RIEWE, M. E. 1997. Grazing management and utilization of ryegrass. Chapter 6. In Rouquette, F. M., Jr. and L. R. Nelson (ed.) Ecology, Production, and Management of Lolium for Forage in the US. CSSA Special Publication 24. Madison, WI.
HABY, V. A., ROUQUETTE, F. M., JR., DAVIS, J. V., LEONARD, A. T., EVERS, G. W., HONS, F. M., and REEVES, S. A. 1997. Alfalfa production on acid, humid-region soils. p. 265-269. In Proc. Am. Forage Grassl. Conf. Ft. Worth, TX. Am. Forage Grassl. Council. Georgetown, TX.

Progress 01/01/96 to 12/30/96

Outputs
Forage utilization strategies, method of grazing, and stocking rate are important for optimum use of pastures. Bermudagrass pastures stocked at 3 levels were grazed with Hereford x Brahman dams and their Simmental-sired calves. Average daily gains (ADG) for cows and calves, respectively, were from continuously high stocked (2.2 pair/ac) -2.0 and 1.3 lbs, from medium stocked (1.3 pair/ac) -.75 and 2.2 lbs, and from low stocked bermudagrass pastures (.8 pair/ac) +.7 and 2.4 lbs/day. Cow and calf pairs which grazed bermudagrass at a stocking rate of 1.5 pair/ac (medium) in an 8-paddock, 3-herd rotation had respective cow and calf ADG of .75 and 2.8 lbs for 1st grazers, .5 and 2.5 lbs for 2nd grazers, and .35 and 2.1 lbs/day for 3rd grazers. The influence of rest (14 to 16 days) and forage availability allowed the first grazers to maximize individual gains on bermudagrass. In addition, pasture utilization was optimized as the 3rd grazers consumed forage to a stubble height of less than 2 inches. Weaned steers and heifers (600 lbs) grazed bermudagrass in a 3-herd, 11- paddock rotation schedule and had ADG of 1.6, .5, and -.4, respectively, for 1st, 2nd, and 3rd grazers. Calves stocked at the same rate but continuously grazed had ADG of .6 lbs/day, and with the addition of 2 lbs/hd/day of a 24% protein supplement gained 1.0 lb/day. Utilization strategies for bermudagrass pastures should include class and activity of animals to allow for optimum gain per animal and per acre.

Impacts
(N/A)

Publications

ROUQUETTE, F.M., JR., LONG, C.R., RANDEL, R. D., MONTGOMERY, T.H, and COLEMAN, S.W. 1996. Carcass characteristics of half-Simmental, Angus x Brahman, Tuli x Brahman, and Brahman steers. RCTR 96-1:91-92.
ROUQUETTE, F.M., JR., BOLEMAN, S.L., MILLER, RHONDA K., LONG, C.R., RANDEL, R.D., MONTGOMERY, T. H., and COLEMAN, S.W. 1996. Sensory traits of Brahman and Tuli crossbred steers. RCTR 96-1:93-94.
ROUQUETTE, F.M., JR., FLORENCE, M.J., KERBY, J., NIMR, G., LONG, C.R., RANDEL, R. D., and COLEMAN, S.W. 1996. Tropically adapted steers grazing winter pasture at Overton, TX and El Reno, OK. RCTR 96-1:55-56.
ROUQUETTE, F.M., JR., FLORENCE, M.J., KERBY, J., NIMR, G., LONG, C. R., and RANDEL, R.D. 1996. Growth and reproduction of Brahman, Angus x Brahman, and Tulix Brahman heifers on pasture. RCTR 96-1:77-78.
ROUQUETTE, F.M., JR., FLORENCE, M.J., LONG, C.L., RANDEL, R. D., and COLEMAN, S.W. 1996. Feedlot performance of four breed types of steers. RCTR 96-1:89-90.
ROUQUETTE, F.M., JR., FLORENCE, M. J., KERBY, J., NIMR, G., LEONARD, A., DAVIS, mJ., and HABY, V.A. 1996. Survival of `Alfagraze' alfalfa under rotational grazing. Res. Ctr. Tech. Rept. 96-1:15-16.
ROUQUETTE, F.M., JR., FLORENCE, M. J., KERBY, J., NIMR, G., LEONARD, A., DAVIS, J., and HABY, V.A. 1996. Response of `Alfagraze' alfalfa and Coastal bermudagrass to rotational grazing. RCTR 96-1:17-18.

Progress 01/01/95 to 12/30/95

Outputs
Grazing behavior and forage passage kinetics are important indicators of animal performance, and also have use in evaluating livestock breed type x environmental interactions. Semen from Tuli cattle was imported into Texas from Australia so this Sanga, African breed could be evaluated for performance traits. Four beef breed types, Angus (AN), Brahman (BR), Angus x Brahman (AB), and Tuli x Brahman (TB), were fitted with vibracorders and dosed with Ytterbium (Yb) to quantify grazing behavior and passage kinetics. On bermudagrass pastures in East Texas, BR and TB heifers (750 lb) had the longest total grazing time overall, and restricted their grazing primarily to the daylight hours. The AN grazed longer than the other breeds during darkness, but overall, had fewer grazing bouts than the other breeds (P<0.04). Time spent resting in the shade in August differed between breeds (P<0.004). Using Yb as a pulse-dose marker revealed differences between breed types in passage of feedstuffs in the rumen (P<0.004), through the whole tract (P<0.04), and time delay to first appearance of the marker (P<0.004). In ingestive behavior, TB resembled BR heifers; however, in passage kinetics, TB heifers were similar to AN and AB. The AN had the slowest rate of passage; thus, the observed reduction in grazing time suggests a lower intake of grazed forage by AN heifers. These foraging traits are primarily responsible for the lowered gains of AN cattle in the southeastern U.S. compared to Bos indicus crossbred and pure.

Impacts
(N/A)

Publications

Progress 01/01/94 to 12/30/94

Outputs
Forage utilization strategies under grazing often include pasture rotation schedules. In an attempt to optimize forage utilization and animal performance, bermudagrass was rotationally grazed with three separate herds of beef cattle. Nine pastures (2.5 to 3 ac each) were grazed with herds each consisting of Brahman x Hereford (F-1) cows and their 5-month-old Simmental-sired (SIMX) winter-born calves, weaned 10-month-old fall-born SIMX steers, and 15-month-old spring born Brahman steers (BRAH). Herds grazed in adjacent pastures and moved in tandem after a 2 to 4-day residence time. Differences in forage available for grazing ranged from an abundance of leaves for the first grazers to a high percentage of stems in the remaining stubble for the third (last) grazers. Two-year averages of daily gain (ADG) of suckling SIMX calves from the 1st, 2nd, and 3rd herds were 2.23, 1.76, and 1.49 lbs, respectively. The F1 cow ADG from these respective 1st, 2nd, and 3rd herds were .70, -.06, and -.26 lbs. Weaned SIMX steers had ADG of .91, .43, and .04; whereas, weaned BRAH steers had ADG of 1.48, .81, and .51, respectively, from the 1st, 2nd, and 3rd herds. Thus, suckling SIMX calves gained 1.3 to 1.4 lbs/da more than weaned SIMX steers irrespective of herd. This multiple herd rotational grazing system resulted in animal gains similar to that from different stocking rates. The more complete the utilization of bermudagrass, the lower the individual animal performance.

Impacts
(N/A)

Publications

Progress 01/01/93 to 12/30/93

Outputs
Optimum utilization of Coastal bermudagrass by grazing cattle in the humid southeastern US presents management problems due to forage dry matter fluctuations. Method of use was evaluated via continuous vs rotationally stocked during two consecutive years from June to October, using 650-lb stocker calves to graze Coastal bermudagrass pastures as follows: (1) 1 herd, continuously (CON); (2) 1 herd, 6 paddock rotation (RT1); and (3) 2 herds, 6 paddock rotation (RT2). Stocking rates were moderate and similar among treatments at about 3 calves per acre. Calves in RT2 were in adjacent paddocks and were rotated at the same time as calves in RT1 (2 to 3-day). The two-year cattle average daily gains (ADG) were 1.07 lbs/da for CON and 1.01 for RT1. For the RT2 treatment, calves in the first group had ADG of 1.51 lbs/da; whereas, calves in the second group had ADG of 0.71 lbs/da. Our data indicated that optimum management systems to match utilization objectives with animal performance expectations may be accomplished by using multiple herds (various classes) of cattle in a rotationally stocked grazing system. Alternative management systems to improve stocker ADG grazing bermudagrass may also be attained via supplementation with undegraded intake protein sources. Fishmeal (FIS) or feathermeal (FEA) were mixed with ground corn to provide a 34.5% protein supplement and each was fed at 1.25 lbs/da. Steer (475 lbs) ADG was 1.17 lbs for pasture only, 1.57 lbs for FIS, and 1.82 lbs for FEA.

Impacts
(N/A)

Publications

Progress 01/01/92 to 12/30/92

Outputs
Sustained pasture production from adapted forage species is a primary factor affecting resource conservation and economic returns. Both Coastal (CS) and common (CM) bermudagrass pastures, which were fertilized identically and each grazed at three stocking rates (SR) for 16 years, were divided into N and non-N ferilizer treatments to evaluate the extent of nutrient cycling on vigor and stand maintenance of forages. Following 7 years with no N fertilization, CS and CM pastures that were oversown with Trifolium sp. and fertilized with K were well sustained when grazed at medium to low SR. At high SR, however, CM was thinned more than CS (18% vs. 11% bare ground), and CM also had more species invasion than CS (4% vs. 1.4%) on the non-N fertilized pastures. Grazed CS and CM pastures growing in acidic, inherently low fertile soils may be sustained at low to moderate SR without the use of fertilizer N provided a moderate source of plant food nutrients is available for recycling. Although animal performance, as measured either on a per animal or per unit land area basis, favored the N-fertilized treatment, the annual fertilizer costs per pound of calf gain were lower for the non-N, clover treatments by approximately 4-fold.

Impacts
(N/A)

Publications

Progress 01/01/91 to 12/30/91

Outputs
Several factors influence the extent of nutrient cycling in pasture ecosystems, but the effect of stocking rate and forage species may have the most dramatic impact under grazing conditions. Coastal (CS) and common (CM) bermudagrass were each grazed at 3 different stocking rates during a 5-year period. Within each stocking rate of both CS and CM, either ryegrass (RG) plus N or clover (CL) plus K(subscript 2)O were overseeded. The CS + RG pastures produced from 185 to 302 lbs/ac more calf gain than CS + CL. The CM + RG pastures produced from 96 to 345 lbs/ac more calf gain than the CM + CL pastures. The stocking rate advantage for CS + RG vs CS + CL ranged from 0.27 to 0.48 cow-calf units per acre. The CM + RG advantage over the CM + CL pastures was .05 to .23 cow-calf units per acre. Preliminary economic assessments indicated that pasture fertilizer costs favored the CL + K(subscript 2)O treatments by 4 to 5 times that of the RG + N treatments. Costs per pound of calf gain were optimized at the medium stocking rates for both fertilizer treatments. A 5-year trial examined the effect of using cowpeas as a green manure crop vs N fertilizer for rye-ryegrass pastures grazed by stocker cattle. The N-fertilized pastures produced the most forage and had an average stocking rate of 3.4 calves/ac and 897 lbs gain/ac; whereas, the non-N fertilized pastures accommodated 2.2 calves/ac and produced 689 lbs gain/ac. Although the costs of gain were similar approximately $.

Impacts
(N/A)

Publications

Progress 01/01/90 to 12/30/90

Outputs
Quantity of forage available for consumption in pastures may affect animal performance, forage quality, and forage production. The long-term effects of stocking rates also influence the extent of nutrient recycling in a grazed area. Both common (CM) and Coastal (CS) bermudagrass pastures were overseeded with either arrowleaf clover or annual ryegrass and grazed at 3 intensities for a 5-year period. In CM pastures, stocking rates for the clover + K(2)O (CLV) vs ryegrass + N (RYG) pastures were similar for the medium (MD) and low (LO) levels at 1.43 and .85 cow-calf units/ac (AU/ac), respectively. The high (HI) stocked RYG pastures were stocked at 2.15 AU/ac; whereas, the CLV was stocked at 1.92 AU/ac. Resultant calf gains for these RYG vs CLV systems were 624 vs 279, 664 vs 568, and 482 vs 371 lbs/ac, respectively for HI, MD, and LO stocked CM pastures. Average stocking rates for CS pastures overseeded with either CLV or RYG were 2.82 vs 3.21, 1.50 vs 1.98, and .92 vs 1.19 AU/ac, respectively, for HI, MD, and LO stocked treatments. The average calf gains per acre for the CLV vs RYG systems were 709 vs 1011, 653 vs 897, and 446 vs 631 lbs/ac, respectively, for HI, MD, and LO stocked CS pastures. In the CS pastures, there was no major dry matter production decline during the 5-year period in which N was not applied. In the CM pastures that received no N fertilizer, however, annual weeds and bahiagrass increased.

Impacts
(N/A)

Publications

Progress 01/01/89 to 12/30/89

Outputs
Forage availability affects animal performance, such as daily gain, and along with forage species and fertilization, influences total gain per unit land area. Common and Coastal bermudagrass pastures were each overseeded with `Yuchi' arrowleaf clover and fertilized at the annual rate of 0-0-112 kg/ha (N-P(2)O(5)-K(2)O), or with `Marshall' ryegrass and fertilized with an annual rate of 390-0-0 kg/ha (N-P(2)O(5)-K(2)O). During the fifth year of this nutrient recycling study designed to assess forage and animal response to clover-potassium vs ryegrass-nitrogen in bermudagrass pasture systems, the following trends were apparent: Ryegrass was a more reliable forage than clover and also produced more total dry matter as indicated by length of grazing period (100 vs 60 days); Daily gains of suckling calves on lightly stocked pastures were greater on clover (1.52 kg/d) compared to ryegrass (1.29 kg/d); At near maximum utilization, but comparable levels of available forage, ryegrass-nitrogen pastures produced more calf gain per acre than clover-potassium pastures on both common bermudagrass (680 vs 170 kg/ha) and Coastal bermudagrass (1205 vs 730 kg/ha); On moderate to lightly stocked pastures, the 200-day gain advantage for ryegrass-nitrogen pastures was approximately 140 kg/ha on common bermudagrass and 250 to 415 kg/ha on Coastal bermudagrass pastures.

Impacts
(N/A)

Publications

Progress 01/01/88 to 12/30/88

Outputs
The level of forage available for consumption directly affects animal performance. Bermudagrass pastures were oversown with rye-ryegrass-arrowleaf clover and grazed at four levels of forage availability with yearling and first calf Brahman x Hereford cattle (F-1). A variable stocking rate method was used to graze pastures to approximately <500, 1500, 2500, and >3500 kg/ha of available forage which were respectively designated as HI, MH, ML, and LO stocking rates. Yearling F-1 heifers had daily gains of .05, .22, .43, and .42 kg, respectively from HI, MH, ML, and LO stocked pastures from April to October. Lactating, first calf F-1 heifers gained -.31, -.22, .07, and .02 kg/da, respectively from HI, MH, ML, and LO stocked pastures; and their Braford-sired calves had respective daily gains of .55, .63, .76 and .77 kg. Spring-born 1/2 Simmental x 1/4 Brahman x 1/4 Hereford calves and Brahman calves grazed rye-ryegrass pastures and were assigned to either pasture only (PAS), or received a fishmeal-based (FIS) or corn-based (CRN) supplement, both of which contained monensin, from February to June. Gain of calves assigned to PAS and FIS were similar at 1.01 and 1.07 kg/da, respectively. Calves which received CRN gained more (1.30 kg/da) than the other groups (P<.01). Conversion of supplement to extra grain (kg:kg) was 3.9:1 and 1.8:1, respectively, for calves assigned to FIS or CRN.

Impacts
(N/A)

Publications

Progress 01/01/87 to 12/30/87

Outputs
Animal performance from grazed pastures is dependent upon level of available forage and nutritive value of the selected diet. Coastal, Tifton 44 an common bermudagrass pastures were oversown with ryegrass and clover and grazed to three levels of available forage with Brahman x Hereford cows and their Simmental-sired calves. Pastures which were continously grazed to forage availability levels of <750 kg/ha, measured to ground level, severely restricted average daily gain (ADG) of both cow and calf.fPastures which were grazed to a forage availability of greater than or equal to 2500 kg/ha permitted calves to have ADG greater than or equal to 1.25 kg. Near maximum ADG from lactating cows grazing these types of forages did not occur until the level of available forage was greater than or equal to 3500 kg/ha. Fall-born calves weaned in June were grazed on bermudagrass pastures and offered various sources and rates of protein supplements. Calf ADG on pasture without supplemental protein was .38 kg, and with supplemental protein ranged from .50 to .70 kg. This significant increase in gain (.12 to .32 kg) was obtained with conversion of supplement:gain which ranged from about 1:1 to 3:1. The protein sources were characterized as moderate to high by-pass materials. Spring-born calves weaned in October were grazed on rye-ryegrass pastures and offered either a protein (50% fishmeal) or energy (86% corn) supplement (both with monensin). Calf ADG on non-supplemented pasture was 1.09 kg.

Impacts
(N/A)

Publications

Progress 01/01/86 to 12/30/86

Outputs
Grazing pressures can dramatically affect plant and animal responses. Both Coastal (CS) and common (CM) bermudagrass pastures which had been previously stocked at either a high (H), medium (M) or low (L) rate (SR) and fertilized with annual rates of 224-110-110 kg/ha of N-P(2)O(5)-K(2)O were each divided into two paddocks to ascertain the influence of nutrient recycling on forage-animal production. One paddock was overseeded with clover and received 0-0-110 kg/ha K(2)O; whereas the other paddock was overseeded with annual ryegrass and received 390kg/haN. Cow-calf pairs were used to evaluate animal performance from March-October. Forage availability (FA) average 1200 (H), 2500 (M) and 5000 (L) kg/ha for CS, and 1000 (H), 2000 (M) and 3000 (L) kg/ha for CM. In CS pastures, ryegrass-N produced 612, 250, and 153 kg/ha more calf gain at H, M, and L, respectively, than clover-K(2)O. In CM pastures, the gain advantage of ryegrass-N over clover-K(2)O was 226, 127, and 86 kg/ha calf gain, respectively, for H, M and L. The average SR (animal units/ha) at H, M and L was 7.5, 4.3, and 2.7, respectively, for CS; and 5.0, 3.4, and 1.9, respectively, for CM. Both CS and CM pastures were soil cored in late May to measure the root-rhizome mass at 0-15 cm and 15-45 cm depths. Root rhizome mass at the 0-15 cm depth from H, M and L SR was 3485, 3903, and 4667 kg/ha, respectiely, for CS, and 2192, 2278, and 2778 kg/ha, respectively, for CM.

Impacts
(N/A)

Publications

Progress 01/01/85 to 12/30/85

Outputs
Relationships which occur at the plant-animal interface are important considerations in defining forage-animal grazing systems. Coastal bermudagrass was grazed at 4 grazing pressures (GP) to achieve various levels of available forage (AF). Levels of AF ranged from 980, 1730, 2480 and 3970 lb DM/ac for high (H), medium high (MH), medium low (ML), and low (L), respectively. Forage growth rate (FGR) did not differ among GP levels, although the relationship of FGR divided by (AF at the initiation of a period) increased as GP increased. With increases in GP, % green stem in AF decreased and % green leaf and dead forage in the pasture increased. Neutral detergent fiber (NDF) content of leaf in both AF and diet decreased as GP increased. The GP did not affect NDF of stems in AF or diet. Differences existed among GP levels in % leaf in AF, but there were no differences in % leaf of the diet among GP. The organic matter digestibility of the diet was highest at MH and L. The organic matter intake (OMI) of weaned steers and lactating cows was highest on ML and lowest on H. The OMI of suckling calves declined as GP was reduced. Grass from L had an erect form and a high tiller density; whereas, grass from H had reduced tiller density and short, thick stolons growing horizontal to the ground. Although diet quality was improved as GP was increased, the increased competition for AF and restricted nutrient uptake resulted in depressed gains with increasing GP.

Impacts
(N/A)

Publications

Progress 01/01/84 to 12/30/84

Outputs
Gain per animal and gain per acre relationships are important considerations in the definitive aspects of forage-animal grazing systems. Coastal bermudagrass was overseeded with 'Marshall' ryegrass and 'Mt. Barker' subterranean clover and grazed continuously from February 24 to September 26 with F-1 (Brahamn x Hereford) cows and their Simmental-sired calves at four grazing pressures (GP). Respective forage availability (lb DM/ac) and GP (lb DM/100 lbs body weight) at the four stocking rates were for low (L) 3522 and 142; medium low (ML) 2112 and 62; medium high (MH) 1618 and 38; and high (H) 921 and 12. The resultant stocking rates based on 1500 lb-animal unit (AU) equivalent for the 210-day trial were 1.6, 2.0, 2.6, and 3.9 Au/ac, respectively, for L, ML, MH, and H. The average daily gain (ADG) of cows at L, ML, MH, and H were .6, .35, -.34, and 1.57 lbs, respectively. Calf ADG were 2.64, 2.23, 2.04, and 1.30 lbs, respectively, for L, ML, MH, and H. Gains per acre for L, ML, MH, and H were 870, 941, 1127, and 1141 lbs, respectively. Sixteen bermudagrass hybrids were evaluated for yield and vigor under mob-grazing conditions. Coastal bermudagrass ranked second with more than 12 tons DM/ac; whereas, Tifton 44 ranked fifteenth with approximately 8 tons DM/ac. Because of lack of drought tolerance, Tifton 44 does not appear to be a suitable replacement for Costal bermudagrass in East Texas.

Impacts
(N/A)

Publications

Progress 01/01/83 to 12/30/83

Outputs
Plant response to defoliation are essential parameters in the construction and manipulation of forage-animal grazing system. Coastal was grazed continuously with cows and calves at four different grazing pressures (GP) (kg forage DM/kg animal liveweight) using a put-and-take stocking rate to adjust GP. The resultant GP were Low (L) 179; Medium Low (ML) 76; Medium High (MH) 28; and High (H) 7. Forage samples were taken to estimate forage availability (FA), DM, and leaf:stem ratios. Esophageal extrusa (EE) samples were taken in early, mid- and late-summer and separated into leaf:stem components. Neutral detergent fiber (NDF) analyses were made on both FA and EE. The average FA during the three measurement periods were 5050, 2800, 1500 and 850 kg/ha DM, respectively, for L, ML, MH, and H. The leaf fraction in FA samples were 40, 43, 40, and 52%, respectively for L, ML, MH, and H; whereas, the leaf proportions of the EE were 83, 79, 81, and 79%, respectively, for L, ML, MH, and H. The NDF content of FA leaf and stem, and EE stem ranged from 71 to 76% for the four GP. The NDF content of EE leaf, however, was 72, 69, 66, and 60%, respectively for L, ML, MH, and H. Data from this trial reveal the selectivity and preference for leaf components by grazing animal and that increased GP decreases the average age of FA and consumed forage and decreases the NDF content of the selected diet.

Impacts
(N/A)

Publications

Progress 01/01/82 to 12/30/82

Outputs
Warm-season perennial grasses form the basic pasture unit for cattle in East Texas. Both yield and quality of these pastures can be improved by overseeding with clover and ryegrass. Common (CM) and Coastal (CS) bermudagrass was oversown with Mt. Barker subterranean clover and ryegrass, and Yuchi arrowleaf clover and ryegrass, respectively, and grazed to 3 levels of forage availability (FA) with cows and calves from March 10 to July 27. FA was measured to 0 cm. height and averaged less than 200 kg./ha. on the low (L) FA, 850 kg./ha. on the medium (M) FA, and greater than 2,500 kg./ha. on the high (H) FA paddocks. Average daily gains (ADG) from L, M, and H FA paddocks of CM were -.37 and .47; .31 and 1.24; and .62 and 1.22 kg., respectively for cows and calves. ADG from L, M, and H FA paddocks of CS were .20 and .68; .55 and 1.23; and .68 and 1.23 kg., respectively for cows and calves. One group of cows which grazed H CS and their calves allowed ad lib creep feed had cow-calf ADG of .50 and 1.42 kg., respectively. In a seeding rate x method of planting trial with subterranean clover, ryegrass, and Tifton 44 bermudagrass, drilled plantings of clover produced 49% more forage than broadcast plantings; whereas, there was only an 11% advantage for ryegrass under similar planting conditions. Ryegrass planted alone and fertilized with nitrogen produced 6122 kg./ha. forage, respectively.

Impacts
(N/A)

Publications

Progress 01/01/81 to 12/30/81

Outputs
The overseeding of warm season perennial grasses with ryegrass and/or clover improves the distribution and total dry matter production as well as the nutritive value of pastures. Arrowleaf clover (Ar) and subterranean clover (sb) was drilled or broadcast at 4 seeding rates in a 'Tifton 44' bermudagrass sod with and without ryegrass (Rg). The Ar plots produced more total dry forage than the Sb plots (15,725 vs 11,450 kg/ha). Seeding rate of clover did not affect total yield; however, early season clover yields increased with: increasing seeding rate; absence of Rg; and drilled. Yields from Rg plots without clover were nearly double those plots which contained both Rg and clover. Coastal bermudagrass was oversown with Ar ang Rg and grazed to 3 levels of forage availability (FA) with cows and calves for a 133-day period (February 26 to July 8). Average FA measured to 0 cm height was 200, 880, and 2,250 kg/ha for high (H), medium (M), and low stocked (L) pastures, respectively. The L pastures had both a creep fed (CF) and non-fed (NF) animal group. Resultant stocking rates were 2.0, 2.0, 3.4, and 6.7 cow-calf units/ha, respectively for LCF, LNF, MNF, and HNF groups. Weaning weights from LCF (358) and LNF (333) were significantly greater (P less than .05) than from MNF (295) and HNF (271 kg). Both steers and heifers were slaughtered at weaning with one side of each carcass receiving an electrical stimulation (ES). Sex of calf did not affect any of the physical or sensory traits evaluated.

Impacts
(N/A)

Publications

Progress 03/01/80 to 12/30/80

Outputs
Plant and animal production potentials are essential components to biological and economical forage utilization parameters. Common bermudagrass (Cm) was oversown with Mt. Barker subterranean clover and ryegrass and Coastal bermudagress (Cs) was oversown with Meechee arrowleaf clover and ryegrass and grazed to 3 levels of forage availability (FA) with cows and calves from February 26 to September 26. Forage was harvested to a O cm height of each of the low (low, medium (M) and high (H) FA paddocks. Average FA during the test period for Cm was 128, 461 and 1635 kg/ha dry matter (DM), respectively for L, M, and H. The L, M and H FA paddocks of C resulted in respective stocking rates of 4.64, 2.91, and 1.61 cow-calf pair (AU)/ha. Average FA for Cs was 264, 1587 and 5321 kg/ha DM for L. M and H, respectively; and supported stocking rates of 7.98, 3.24 and 2.12 AU/ha. Fall-born calves slaughtered at weaning weighed 277, 295 and 346 kg from L. M and H FA Cm paddocks; and 274, 295 and 323 kg from L, M and H FA Cs paddocks. Creep fed calves grazing H FA Cs paddocks had weaning weights at slaughter of 359 kg. A 75-day grazing trial during late summer compared F-1 (Brahman x Hereford) cows and 1/2 Simmental calves vs purebred Brahman cows and Brahman calves. Paddocks grazed to L, M and H FA resulted in F-1 cow gains of -.98, .06 and .35 kg/da, and Brahman cow gains of -.93, -.20 and .11kg/da, respectively.

Impacts
(N/A)

Publications