MANAGEMENT AND ENVIRONMENTAL FACTORS AFFECTING NITROGEN CYCLING AND USE EFFICIENCY IN FORAGE-BASED LIVESTOCK PRODUCTION SYSTEMS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: TERMINATED
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1005233
• Project No.: ARK02466
• Multistate No.: NC-_old1182
• Project Start Date: Nov 6, 2014
• Project End Date: Sep 30, 2019

Project Director
Coffey, KE, P..

Recipient Organization
UNIVERSITY OF ARKANSAS
(N/A)
FAYETTEVILLE,AR 72703

Performing Department
Animal Sciences

Non Technical Summary
Increased demand for meat products by consumers during past decades has encouraged producers to respond with an increased intensification of forage-based livestock production. Our experiments will examine alternative strategies to enhance legume establishment and persistence, improve N harvest efficiency, and reduce greenhouse gas (GHG) footprints in pastures; assess secondary plant metabolites in forage legumes for increased N retention and altered N cycling in dung and urine excretions from grazing ruminant animals; and quantify the effects of intensive pasture management strategies on N harvest efficiency and spatiotemporal patterns of N cycling in grassland agro-ecosystems. Expected outcomes and predictions will include advice on management strategies in terms of N use efficiency, particularly as it relates to the capture and excretion of N in the environment. In addition, this work will facilitate the identification forage systems that minimize N inputs and production costs.

Animal Health Component

10%

Research Effort Categories

Basic

15%

Applied

85%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
302	1699	1010	40%
302	1649	1010	60%

Knowledge Area
302 - Nutrient Utilization in Animals;

Subject Of Investigation
1699 - Pasture and forage crops, general/other; 1649 - Forage legumes, general/other;

Field Of Science
1010 - Nutrition and metabolism;

Keywords

nitrogen-use efficiency

legumes

ruminant animals

Goals / Objectives
Evaluate legume cultural and management strategies emphasizing legume establishment, N cycling and use efficiency, and GHG emissions. (AR, KY, NE, UT). Specific objectives: (i) Identify practices that optimize legume establishment and persistence. (ii) Compare N cycling and use efficiency of ruminants grazing pastures with and without forage legumes. (iii) Determine the impact of legumes on the GHG footprint of livestock production systems. Assess the efficacy of secondary plant metabolites in legume species for increasing N retention and improving N cycling in forage-livestock systems. (AR, KY, MI, UT) Specific objectives: (i) Evaluate effects of birdsfoot trefoil, a tannin-containing legumes, on N partitioning in dung and urine excretions. (ii) Determine soluble phenolic and genotypic effects on forage legume protein fractionation and nitrogen availability. (iii) Evaluate effects of genetic variability in tannin concentration on soil N availability in mixed birdsfoot trefoil/tall fescue swards. Quantify effects of pasture management strategies on N use efficiency by ruminant animals and N cycling in herbage and soils of grassland agro-ecosystems. (AR, NE, MI, OK) Specific objectives: (i) Investigate effects of management strategies that alter spatiotemporal distribution of grazing and nutritive value of forage on ruminant performance and N harvest efficiency. (ii) Evaluate effects of management strategies on herbage mass and accumulation, nutritive value, botanical composition, and N use efficiency across growing seasons and pasture landscapes. (iii) Determine N pool and cycling responses to management strategies across variable soil environments and climatic conditions. (iv) Evaluate byproduct supplementation as a source of N for annual forages in integrated cropping livestock systems. Disseminate research results through coordinated extension/education activities, including extension publications, university course material, and regional and state conferences on nitrogen cycling and use efficiency and management of grass-legume mixtures. (AR, KY, MI, NE, OK, UT)

Project Methods
Multiple types of legumes will beplanted in monoculture legume banks associated with grass pasturesto enhance legume persistence and reduce risk to producers for adopting these practices. These legume banks will be compared with overseeded legume-grass pastures.Teff, an annual summer grass, will be seeded into plots that had annual legumes (crimson clover, arrowleaf clover, and hairy vetch) in them the year before. Forage production and quality (including N content) of teff in the legume plots will be compared to plots of teff fertilized at different rates (0 to 150 kg N ha-1). These data will be used to estimate the amount of N made available for teff production by the legumes.Gas emission samples will be taken at 1, 2, and 5-7 days after manure deposition events after ruminants have grazed different legume banks.Grazing methods that result in varied manure and urine distribution within a pasture will be assessed for their impact on nitrogen use efficiency and N pools and pulses in herbage, soil, and animal resources..

Progress 11/06/14 to 09/30/19

Outputs
Target Audience:The target audience for this project is cattle and small ruminant producers and professional educators in the Southeastern,and Midwestern US. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate and graduate students were trained to conduct different types of experiments and to collect pertinent samplesand data. Graduate students wrote research reports, scientific abstracts, and presented information at professional meetingsas well as wrote manuscripts for publication in scientific journals. How have the results been disseminated to communities of interest?Information was presented at professional scientific meetings and published in peer-reviewed journals after completion. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Alfalfa was harvested in June, 2018 at 75% bloom, chopped, and then packed at 55% moisture into plastic-lined bins andallowed to ensile for 3 months. Alfalfa silage was either offered alone or mixed with 9, 18, or 27% sericea lespedeza to non-pregnant, non-lactating ewes. Digestibility of dry matter and organic matter along with digestible dry matter and organicmatter intake decreased with increasing SL addition to the diet. Digestibility of fiber components also decreased withincreasing SL. Urinary nitrogen excretions tended to decrease while fecal nitrogen excretion tended to increase withincreasing SL proportion in the diet. Therefore, supplementation with sericea lespedeza as a tannin source to alfalfa silagedecreased forage digestibility and digestible organic matter intake and did not positively influence nitrogen use.Alfalfa was harvested in October 2018 at 75% bloom, chopped, and then packed at 55% moisture into plastic-lined bins,where it was allowed to ensile for 3 months. Alfalfa silage was either offered alone or mixed with 9, 18, or 27% lablabpurpureus hay (LP) on a dry matter basis to pregnant ewes. Dry matter and organic matter intake increased with 9% lablab,but then decreased with additional lablab in the diet. Digestible dry matter and organic matter intake tended to decrease byincreasing the proportion of LP in diet. Increasing LP in the diet reduced N excreted in the urine, but did not impact proteinuse or retention in the animal. Therefore, adding a forage with moderate concentrations of polyphenols can improve forageutilization by ruminants but may not improve nitrogen-use efficiency.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Niyigena, V., K. P. Coffey, W. K. Coblentz, D. Philipp, R. T. Rhein, A. N. Young, J. D. Caldwell, and B. C. Shanks. 2019.Intake and digestibility by gestating sheep offered alfalfa silage wrapped with plastic with or without an oxygen-limitingbarrier after extended time delays. An. Feed Sci. Technol. 254:114193
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Diaz, J., K. P. Coffey, W. K. Coblentz, D. Philipp, V. Niyigena, M. C. Pruden, D. Myers. 2019. Digestibility of sheepoffered tall fescue, meadow fescue and orchardgrass grasses ensiled with slurry or commercial urea fertilization. ASAS,Annual Meeting, Austin, TX.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Niyigena, V., K. P. Coffey, W. K. Coblentz, D. Philipp, C. Althaber, R. T. Rhein, and M. C. Pruden. 2019. Intake,digestibility, and rumen fermentation in sheep offered alfalfa silage alone or alfalfa and tall fescue mixtures harvested aftera killing frost. Annual Meeting of ASAS. July 8-11, 2019. Austin, TX.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Niyigena, V., K. P. Coffey, W. K. Coblentz, D. Philipp, M. C. Savin, J. Zhao, J. Diaz, S. P. Park, and S. l. Shelby. 2019.Effect of supplementing different proportions of sericea lespedeza with alfalfa silage on intake, digestibility, and nitrogenbalance in sheep. Annual Meeting of ASAS. July 8-11, 2019. Austin, TX.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Niyigena, V., K. P. Coffey, W. K. Coblentz, D. Philipp, M. C. Savin, J. Zhao, J. Diaz, S. P. Park, R. T. Rhein, and M. C.Pruden. 2019. Effect of supplementing different proportions of Lablab purpureus with alfalfa silage on intake anddigestibility in gestating sheep. Proc. Southern For. Past. Crop Improv. Conf. pp. 21.

Progress 10/01/17 to 09/30/18

Outputs
Target Audience:The target audience for this project is cattle producers and professional educators in the Southeastern and Midwestern US. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate and graduate students were trained to conduct different types of experiments and to collect pertinent samples and data. Graduate students wrote research reports, scientific abstracts, and presented information at professional meetings. How have the results been disseminated to communities of interest?Information was presented at professional scientific meetings and published in peer-reviewed journals after completion. What do you plan to do during the next reporting period to accomplish the goals?Multiple silage-based studies are planned. Those include ensiling alfalfa and tall fescue after frost, feeding ensiled alfalfa with different inclusion levels of sericea lespedeza or lab lab, and feeding ensiled tall fescue, orchardgrass, or meadow fescue to sheep. In each study, digestibility and nitrogen balance will be assessed.

Impacts
What was accomplished under these goals? Annual ryegrass (Lolium multiflorum) was baled when it reached either 74% moisture (WET) or 30% moisture (DRY), and then wrapped either the day of bailing (D0) or 1 (D1), 2 (D2), or 3 d (D3) after bailing to produce round-bale silage. The silages were then offered to lambs to determine how the treatments affected forage intake and digestibility. Dry matter intake and intake of digestible dry matter were greater for DRY than WET silage. Generally intake of dry matter and digestible dry matter was greatest from silage wrapped the day of baling and declined thereafter. Impact: A greater number of producers are attempting to make round bale silage rather than hay. This information along with previous work provides producer with information to help them understand which factors are the most important and have the greatest impact on animal preference and performance when making round bale silage from different forages. These studies were supported in part by USDA-ARS specific cooperative agreement 58-3655-4-052. Activities: Data collected: Forage intake, digestibility, nitrogen balance, digestible dry matter and organic matter intake, silage fermentation profiles, and correlations between silage chemical composition and fermentation profiles and intake and digestibility measurements.

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Clark, J. K, K. P. Coffey, W. K. Coblentz, B. C. Shanks, J. D. Caldwell, R. E. Muck, D. Philipp, M. A. Borchardt, R. T. Rhein, W. E. Jokela, E. A. Backes, M. G. Bertram, and W. B. Smith. 2018. Voluntary intake and digestibility by sheep of alfalfa ensiled at different moisture concentrations following fertilization with dairy slurry J. Anim. Sci.96:964-974.
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Hays, M. A., K. P. Coffey, P. A. Beck, W. K. Coblentz, C. P. Weiss, T. S. Crook, and D. Philipp. 2018. Effects of delayed wrapping and moisture content on intake and digestibility of ryegrass silage by growing lambs. J. Anim. Sci. 96(Suppl. 1):31-32 (Abstr.) https:/doi.org/10.1093/jas/sky027.059.
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Huang, Y., S. Shelby, X. Wang, J. Apple, and K. Coffey. 2018. Effect of two dietary crude protein levels on finishing performance, carcass characteristics, and meat quality of lambs. J. Anim. Sci. 96(Suppl. 1):29-30 (Abstr.) https:/doi.org/10.1093/jas/sky027.055.

Progress 10/01/16 to 09/30/17

Outputs
Target Audience:The target audience for this project is cattle producers and professional educators in the Southeastern, and Midwestern US. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate and graduate students were trained to conduct different types of experiments and to collect pertinent samples and data. Graduate students wrote research reports, scientific abstracts, and presented information at professional meetings. How have the results been disseminated to communities of interest?Information was presented at professional scientific meetings and published in peer-reviewed journals after completion. What do you plan to do during the next reporting period to accomplish the goals?Laboratory analyses will be completed on the ryegrass silage study mentioned above so that nitrogen balance can be determined and correlations between various forage quality and fermentation measurements will be correlated with intake and digestibility measurements to help draw proper relationships between these variables. A study evaluating the impacts of ensiling different portions of tannin-containing forages with alfalfa on digestibility and nitrogen balance in sheep is planned. Diets designed to modify the partitioning of nitrogen excretion in urine and feces will be evaluated. The emphasis will be on proper sampling techniques, storage methods, and analytical procedures for the estimation of specific urine components.

Impacts
What was accomplished under these goals? Impacts: Based on information from this project, producer now have better information about how to harvest, package, and feed their alfalfa and ryegrass silages. Delaying wrapping until the day after baling reduced forage intake and digestibility of ryegrass, and nitrogen use of alfalfa. Therefore, silage wrapped the day after baling or even later should be considered inferior in quality and be offered to animals with lower production goals. Analysis of alfalfa silage samples for lactic acid could provide useful information to producers to help them better predict performance by animals consuming alfalfa silage. However, lactic acid and other silage fermentation products were not good predictors of intake and digestibility by lambs offered ryegrass silages. These studies were supported in part by USDA-ARS specific cooperative agreement 58-3655-4-052. Activities: Exp. 1. Large round bales of alfalfa silage were wrapped with plastic either containing or not containing an oxygen-limiting barrier either the day of baling or 1, 2, or 3 days after baling. Pregnant crossbred ewes (n = 16; 3-5 yr. old; 63 ± 1.7 kg) were offered the alfalfa silage from 1 of 8 treatments in a 3-period digestion and nutrient balance study. Correlations between intake and digestibility measurements and silage fermentation characteristics were conducted to determine the best predictors of animal performance from silage fermentation profiles. Exp. 2. Ryegrass silages were baled at low (39%) or high (72%) moisture, then wrapped with plastic either the day of baling or 1, 2 or 3 days after baling. Crossbred lambs were offered the ryegrass silage from these 8 treatment combinations in a 3-period digestion and nutrient balance study. Data collected: Forage intake, digestibility, nitrogen balance, digestible dry matter and organic matter intake, silage fermentation profiles, and correlations between silage chemical composition and fermentation profiles and intake and digestibility measurements. Outcomes: Nitrogen utilization by pregnant ewes was greater from alfalfa bales wrapped with an oxygen-limiting barrier and from bales wrapped the day the alfalfa was baled. Nitrogen intake and N excreted in the urine were not affected by wrap type or time delay after baling. Intake and digestibility of ryegrass silage was generally greater from the lower-moisture silage (30%) vs. higher-moisture silage (74%) and from silage wrapped the day it was baled. Digestible dry matter or organic matter intake was greatest from the alfalfa wrapped the day following baling, but was greatest from ryegrass wrapped the same day the forage was baled. In both instances, digestible forage intake declined rapidly after either a 1-day delay for alfalfa or a delay until the next day to wrap ryegrass bales. Fermentation measurements such as lactic acid were related well with digestible forage intake from alfalfa. However, with ryegrass silage, digestible forage intake was greater from the silages baled at lower moisture, but fermentation profiles were greater and mold and yeast counts were lower from silages baled at higher moisture. Therefore, simply looking at laboratory analyses on ryegrass silages may be somewhat misleading as it pertains to actual animal performance. These studies provide producers with information to help them make better management decisions about how to feed alfalfa and ryegrass silage based on how it was managed after baling.

Publications

• Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Niyigena, V. Effect of Delayed Wrapping and Wrapping Source on Intake and Digestibility of Alfalfa Silage in Gestating Sheep
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Smith, W. B., K. P. Coffey, R. T. Rhein, E. B. Kegley, D. Philipp, J. G. Powell, J. D. Caldwell, and A. N. Young. 2017. Feeding distillers grains, soybean hulls or a mixture of both to cows as a forage replacement: Effects on intake, digestibility, and ruminal fermentation characteristics. J. Anim. Sci. 95:3666-3675.
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Crook, T. S., B. Stewart, M. B. Sims, C. P. Weiss, K. P. Coffey, and P. A. Beck. 2017. The Effects of Moisture at Baling and Wrapping Delay on Storage Characteristics of Annual Ryegrass Round Bale Silage. doi: 10.2527/ssasas2017.026. J. Anim. Sci. 95(Suppl. 1):13.
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Niyigena, V., K. P. Coffey, W. K. Coblentz, D. Philipp, A. N. Young, and R. T. Rhein. 2017. Effect of delayed wrapping and wrapping source on nitrogen balance and blood urea nitrogen in gestating sheep offered alfalfa silage. J. Anim. Sci. 95(Suppl. 4):54.

Progress 10/01/15 to 09/30/16

Outputs
Target Audience:The target audience for this project is cattle producers and professional educators in the Southeastern, and Midwestern US. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate and graduate students were trained to conduct different types of experiments and to collect pertinent samples and data. Undergraduate students wrote research reports and graduate students also wrote research reports, and scientific abstracts and presented the information at professional meetings. How have the results been disseminated to communities of interest?Information was presented at professional scientific meetings. Results were also published in the Department of Animal Science Annual report of progress. What do you plan to do during the next reporting period to accomplish the goals?A nitrogen balance study is planned wherein alfalfa haylage will be evaluated for the impacts of delaying wrapping for different time intervals after baling. Ryegrass silage was baled at two different moisture concentrations and wrapped at various times after baling. A study to evaluate intake, digestibility, and nitrogen balance by lambs is planned. A study evaluating the impacts of tannins in supplements on digestibility and nitrogen balance in sheep is planned. Diets designed to modify the partitioning of nitrogen excretion in urine and feces will be evaluated. The emphasis will be on proper sampling techniques, storage methods, and analytical procedures for the estimation of specific urine components.

Impacts
What was accomplished under these goals? Impacts: Based on information from this project, producers now have better information about how to harvest, package, and feed their alfalfa silage. Delayed wrapping up to one day following baling had no detrimental effects on forage intake and digestibility. Therefore, silage baled under these conditions can be considered as the greatest quality. Silage wrapped beyond 1 day after baling should be considered inferior in quality and be offered to animals with lower production goals. Greater lactic acid concentrations were related positively to greater intake of digestible organic matter which should improve overall energy status of ruminants. Therefore, analysis of silage samples for lactic acid could provide useful information to producers to help them better predict performance by animals consuming alfalfa silage. The study was supported in part by USDA-ARS specific cooperative agreement 58-3655-4-052. Activities: Alfalfa silages were baled, then wrapped with plastic either with or without an oxygen-limiting barrier either the day of baling or 1, 2 or 3 days after baling. Pregnant crossbred ewes (n = 16; 3-5 yr. old; 63 ± 1.7 kg) were offered the alfalfa silage from 1 of 8 treatments in a 3-period study. Silage intake, digestibility, and nutrient balance were measured. Correlations between intake and digestibility measurements and silage fermentation characteristics were conducted to determine the best predictors of animal performance from silage fermentation profiles. Data collected: Forage intake, digestibility, nitrogen balance, digestible dry matter and organic matter intake, silage fermentation profiles, and correlations between silage chemical composition and fermentation profiles and intake and digestibility measurements. Results: Outcomes: Alfalfa silage was baled in large round bales, and then wrapped with plastic either the day of baling, or 1, 2 or 3 days after baling. In general, intake and digestibility were greatest in silage wrapped the day following baling and declined with subsequent time delay between baling and wrapping. This provides producers with information to allow them to make better management decisions about how to feed alfalfa silage based on how it was managed after baling.

Publications

• Type: Theses/Dissertations Status: Published Year Published: 2016 Citation: Niyigena, V. Effect of Delayed Wrapping and Wrapping Source on Intake and Digestibility of Alfalfa Silage in Gestating Sheep. MS Thesis. University of Arkansas
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Coblentz, W. K., K. P. Coffey, and E. A. Chow. 2016. Storage characteristics, nutritive value, and fermentation characteristics of alfalfa packaged in large-round bales and wrapped in plastic after extended time delays. J. Dairy Sci. 99:3497-3511. Smith, S. A., M. P. Popp, D. R. Keeton, C. P. West, K. P. Coffey, L. L. Nalley, and K. R. Brye. 2016. Economic and greenhouse gas emission response to pasture species composition, stocking rate, and weaning age by calving season, farm size, and pasture fertility. Agric. Resource Econ. Rev. 45:98-123. doi:10.1017/age.2016.11.
• Type: Other Status: Published Year Published: 2016 Citation: Scientific Abstracts Coblentz, W. K., K. P. Coffey, and E. A. Chow. 2016. Effects of wrapping time delays n nutritive value of baled alfalfa silages. J. Anim. Sci. 94(Suppl. 5): 321. Coblentz, W. K., K. P. Coffey, and E. A. Chow. 2016. Effects of wrapping time delays on fermentation characteristics of baled alfalfa silages. J. Anim. Sci. 94(Suppl. 5): 320. Niyigena, V., K. P. Coffey, W. K. Coblentz, D. Philipp, A. N. Young, R. T. Rhein, and J. K. Clark. 2016. Effect of delayed wrapping and wrapping source on intake and digestibility of alfalfa silage in sheep. J. Anim. Sci. 94(Suppl. 2): 168. Niyigena, V. K. P. Coffey, W. K. Coblentz, A. N. Young, D. Philipp, H. L. Bartimus, and R. T. Rhein. 2016. Correlation of fermentation characteristics with intake and digestibility of alfalfa silage in gestating ewes. J. Anim. Sci. 94(Suppl. 5):299.

Progress 11/06/14 to 09/30/15

Outputs
Target Audience:The target audience for this project is cattle producers and professional educators in the Southeastern, and Midwestern US. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate and graduate students were trained to conduct different types of experiments and to collect pertinent samples and data. Undergraduate students wrote research reports and graduate students also wrote research reports, and scientific abstracts and presented the information at professional meetings. How have the results been disseminated to communities of interest?Information was presented at professional scientific meetings. Results were also published in the Department of Animal Science Annual report of progress. What do you plan to do during the next reporting period to accomplish the goals?A nitrogen balance study is planned wherein alfalfa haylage will be evaluated for the impacts of delaying wrapping for different time intervals after baling. A study evaluating the impacts of tannins in supplements on digestibility and nitrogen balance in sheep is planned.

Impacts
What was accomplished under these goals? Impacts: Soybean hulls or distillers' grains or a combination of the two were offered to cows as a supplement to low-quality fescue hay. Supplementation with distillers' grains appeared to help better meet both the energy and protein deficiencies that result from feeding poor-quality fescue hay based on ruminal measurements. However, forage intake and digestibility were not different across treatments. Therefore, producers can use commodity prices to dictate purchasing decisions for co-product feedstuffs without having to allow for major differential in expected animal performance based on variations in chemical composition of the different co-product feedstuffs. Activities: Three lactating and 3 non-pregnant, non-lactating ruminally-cannulated crossbred beef cows (680 +/- 18.6 kg body weight; BW) were offered tall fescue hay for ad libitum consumption from large round bales along with supplements fed at 0.5% of BW of each individual cow. Supplements of soybean hulls, distillers grains, or a 1:1 mixture of the two were offered to the cows in a replicated 3 × 3 Latin Square within each production status that continued for 6, 21-day periods. The cows were housed together in a drylot pen and then sorted randomly into individual pens away from their calves each day and offered their respective supplements at 4 PM. Data collected: Forage intake and digestibility, in situ dry matter digestibility, ruminal ammonia, and ruminal volatile fatty acids. Results: Forage and total DM intake (g/kg BW) were greater by lactating cows compared with open cows, but were not different among supplements. Total tract or ruminal digestibilities were not affected by production status or supplement treatment. Ruminal ammonia nitrogen concentrations were greater from cows offered distillers grains compared with those offered soybean hulls or the mixed supplement and ruminal propionate concentrations were greater between 2 and 8 hours after feeding from cows offered distillers grains compared with those offered soybean hulls or the mixed supplement. Total volatile fatty acid concentrations were greater from cows offered soybean hulls than those offered the mixed supplement and from cows offered the mixed supplement compared with those offered distillers grains. Outcomes: When offered at a level of 0.5% of the body weight of cows, producers can use unit prices rather than energy or protein concentrations to base purchasing decisions. This allows producers considerable flexibility when purchasing supplements to meet deficiencies in poor-quality forages.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Kanani, K., D. Philipp, K. P. Coffey, E. B. Kegley, C. P. West, S. Gadberry, J. Jennings, A. N. Young, and R. Rhein. 2015. Diurnal variation in fecal concentrations of acid-detergent insoluble ash and alkaline-peroxide lignin from cattle fed bermudagrass hays of varying nutrient content. J. Anim. Sci. Biotechnol. 6:24 Philipp, D., M. P. Popp, E. R. Rumley, M. C. Savin, and K. P. Coffey. 2015. Regulatory, production, and consumer-based challenges of forage-based cattle production systems in the southeastern United States. Anim. Frontiers 5(4):24-31.
• Type: Other Status: Published Year Published: 2015 Citation: Sanders, O. J., K. P. Coffey, A. N. Young, and K. A. Bottoms. 2015 Intake and digestibility of tall fescue supplemented with co-product feeds. Discovery 16:83-91. Bartimus, H. L., J. D. Caldwell, A. L. Bax, B. C. Shanks, K. P. Coffey, T. Hampton, Y. Liang, S. E. Bettis, and M. Vazquez-Anon. 2015. Performance and blood measurements by Holstein steers supplemented with or without MFP� while grazing cool-season forages. J. Anim. Sci. 93(Suppl. 2):172. Clark, J. K., B. C. Shanks, J. D. Caldwell, K. P. Coffey, W. K. Coblentz, R. E. Muck, D. Philipp, M. A. Borchardt, R. T. Rhein, A. N. Young, M. D. Basham, W. E. Jokela, E. A. Backes, K. A. Center, M. G. Bertram. 2015. Effects of dairy slurry application and bale moisture concentration on voluntary intake and digestibility of alfalfa silage by sheep. J. Anim. Sci. 93(Suppl. s3):615-616. Smyth, E., J. M. Burke, M. Acharya, J. E. Miller, and K. P. Coffey. 2015. Grass finishing systems for lambs born in fall and winter. J. Anim. Sci. 93(Southern Section Abstracts):9-10. Bartimus, H. L., J. D. Caldwell, B. C. Shanks, K. P. Coffey, A. L. Bax, T. Hampton, Y. Liang, S. E. Bettis, and M. Vazquez-Anon. 2015. Growth performance of Holstein steers supplemented with or without methionine while grazing cool-season forages. Arkansas Agri. Exp. Sta. Research Series 628:44-45. Clark, J. K., B. C. Shanks, J. D. Caldwell, K. P. Coffey, W. K. Coblentz, R. E. Muck, D. Philipp, M. A. Borchardt, R. T. Rhein, A. N. Young, M. D. Basham, E. A. Backes, K. A. Center, W. E. Jokela, and M. G. Bertram. 2015. Effects of dairy slurry application and bale moisture concentrations on voluntary intake and digestibility of alfalfa silage by sheep. Arkansas Agri. Exp. Sta. Research Series 628:11-12. Sanders, O., K. Coffey, A. Young, K. Bottoms, and D. Philipp. 2015. Co-product feeds as supplements for cows offered poor quality tall fescue hay. Arkansas Agri. Exp. Sta. Research Series 628:42-43. Bax, A. L., J. D. Caldwell, L. S. Wilbers, B. C. Shanks, T. Hampton, S. E. Bettis, Y. Liang, G. I. Zanton, and K. P. Coffey. 2015. Performance of Holstein steers offered hay and supplement with or without added methionine. Arkansas Animal Science Department Report. Arkansas Agri. Exper. Sta. Research Series 620:14-15. Cummins, R., K. Coffey, N. Jack, K. Jorgan, R. Rhein, D. Philipp, M. Adams, W. Smith, K. Clayton, and A. Young. 2015. Palatability of teff grass by horses. Arkansas Animal Science Department Report. Arkansas Agri. Exper. Sta. Research Series 620:44-49. Smith, W. B., K. P. Coffey, R. T. Rhein, E. B. Kegley, D. Philipp, J. D. Caldwell, and A. N. Young. 2015. Ruminal forage digestibility following a period of limit-feeding co-product feedstuffs. Arkansas Animal Science Department Report. Arkansas Agri. Exper. Sta. Research Series 620:39-41.