Progress 11/01/99 to 10/31/05
Outputs
Feedlot diets have changed drastically over the last 20 years to continually increase the amount of dietary energy and reduce the amount of roughage. This practice results in a greater degree of diet management required to prevent acidosis in feedlot cattle. Therefore, the objective of this research (2004-2005) was to identify the effectiveness of a mineral buffer, Acid Buf (TM), as a feed additive in high concentrate diets to reduce the potential for ruminal acidosis. Two hundred and sixteen crossbred steers with an average weight of 723 lbs were assigned to one of 24 pens. Steers were started on a high concentrate diet similar to that fed in commercial feedlots in the Southern Plains of the United States. The steers were transitioned onto the feedlot diet over a period of 18 days. Three levels of Acid Buf (0, 0.25 and 0.50% of diet dry matter) were fed to steers. Cattle were harvested at an estimated 0.5 inches of external fat over the 12th rib. Arterial blood was
collected from the ear of two animals per pen when steers reached the final feedlot diet (day 18) and on day 46 and 118 of the experiment. Ruminal tissue was collected from the dorsal sac, dorso-caudal blind sac, ventro-caudal blind sac and ventral sac when cattle were harvested. There were no visible lesions on any of the tissues collected. At the beginning of the experiment, steers in each treatment group weighed 717 lb (P=.9998). Harvest weight averaged 1325 lbs and did not differ between treatments (P = 0.5290). The inclusion of Acid Buf to the diet did not affect ADG, gain efficiency or feed intake (P > 0.05). Consequently, the performance results obtained from this experiment does not support the addition of Acid Buf to the diet to increase performance of feedlot cattle fed a high concentrate diets under the parameters used in this experiment. There was no statistical difference in hot carcass weight (P=0.5482), or USDA Carcass Characteristics (P > 0.05) due to level of Acid Buf
included in the diet. The limited response of Acid Buf on carcass characteristics is likely due to the ineffectiveness of Acid Buf to increase feed intake and subsequent rate of gain. Fecal pH tended to be higher (P = 0.1271) in steers fed Acid Buf on day 46 but not later in the experiment. Fecal pH was not determined on day 18. There was no difference in blood pH, pCO2 or PO2 due to level of Acid Buf in the diet. While the blood pH was in the low normal range, the steers did not have any sub-clinical signs of acidosis on days that blood samples were taken. It could be argued that the lack of response of Acid Buf on performance and subsequent carcass characteristics was due to the fact that control animals were not stressed to the point of being subjected to acidotic conditions. Based on the parameters used in this experiment, Acid Buf did not improve animal performance or change carcass characteristics when fed at 0.25 and 0.50% of diet dry matter.
Impacts
A commercial mineral additive (Acid Beef TM) did not improve feedlot cattle performance when fed at 0.25 and 0.50 percent of diet dry matter, under the conditions of a 216-head feeding trial at TAES/ARS, Bushland, Texas.
Publications
- J.T. Vasconcelos, J.E. Sawyer, L.W. Greene, & F.T. McCollum, III. 2005. Effect of Nutritional Management on Intramuscular and Subcutaneous Adipose Tissue Deposition of Growing Beef Steers. Beef Cattle Research in Texas. Published by Department of Animal Science & Texas Agricultural Experiment Station, the Texas A&M University System, College Station, Texas; August. pp. 71-74
- Greene, L.W., & J.T. Vasconcelos. 2005. Manure Concentrations of N, P, Animal Performance, and Blood Urea Nitrogen Concentration of Feedlot Steers Phase-Fed Deficient Levels of Protein. Paper #50. Proceedings, Symposium State of the Science, Animal Manure & Waste Management. National Center for Manure & Animal Waste Management, USDA-CSREES and North Carolina State University, San Antonio, Texas. Jan. 5-7. CDROM.
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Progress 01/01/04 to 12/31/04
Outputs
An in situ experiment was conducted to determine the rate and extent of dry matter disappearance (DMD) of corn grain, sorghum grain, alfalfa hay and brown mid-rib forage sorghum silage in the presence of different strains of yeast. Four mature rumen cannulated non-lactating cows were fed a control diet, or control diet plus 20 g/d P7, 20 g/d SC47 or 40 g/d DV-XP strains of yeast in a 4X4 Latin square design. A 13% high concentrate diet (9.5 kg/d) consisting of 80% steam flaked corn, 10% soybean hulls and 10% protein/vitamin mineral supplement was fed to each cow twice a day (60% at 0800 h and 40% at 1600 h). Yeast strains were top dressed on the respective diet at the morning feeding and mixed by hand. Cows were fed their respective diet in each period of the Latin square for 14 d. On d 12 of each period, duplicate in situ digestion bags (10 X 20 cm) containing substrate (12.5 mg/cm2 of bag surface area) were incubated for 72, 48, 24, 12, 6, 3, 1.5, 0.5 and 0 h.
Immediately after submersion of the 0 h bags of substrate into the ruminal fluid, all bags were removed and rinsed with tap water. After an initial rinse, all bags were rinsed using 4 to 6 times until rinse water was clear. Bags were then dried at 60 C for 48 h and weighed to determine DMD. The rate of DMD for corn grain, sorghum grain alfalfa hay and sorghum sudan silage was 2.7, 2.1, 1.88 and 0.94 %/h, respectively. P7 and SC47 increased (P =0.0075) rate of DMD of corn grain over that of the control and DV-XP (3.28 and 3.43 vs 1.96 and 2.52 %/h, respectively). Yeast strains did not change the rate of DMD of sorghum grain, alfalfa hay or sorghum sudan silage (P > 0.10). The extent of DMD was similar across all treatments for corn grain (95.4%), sorghum grain (89.3%) and alfalfa hay (74.54%). The extent of DMD of sorghum sudan silage was decreased (P = 0.04) when DV-XP was fed compared the control, P7 and SC47 (56.0% vs 76.9, 74.0 and 69.5, respectively). These data indicate that
various yeast strains affect rate or extent of DMD of corn grain and sorghum sudan silage in this study.
Impacts
The data presented strongly suggest that cultures of microbial yeast strains can alter extent and rate of digestion in beef cattle fed high concentrate diets. Increasing the extent of digestion can reduce the nutrient load realized in the nations feedyards. Increasing the rate of digestion will allow for increase appetite as digesta is moved through the digestive tract. The increased intake will reduce the percentage of the daily feed supply contributing to the daily maintenance requirement and increase efficiency of nutrient use for tissue gain and subsequent food production.
Publications
- Silva, J. C., and L. W. Greene. 2004. Rate and extent of in situ DM disappearance of feedstuffs in cows fed different strains of yeast. J. Anim. Sci. 82 (Suppl. 1):41
- Biggs, T. J., M. S. Brown, L. W. Greene, E. M. Cochran, E. A. Lauterbach, and J. R. Cortese. 2004. Effect of dietary crude and degradable protein concentration on feedlot performance, estimated nutrient excretion, and carcass characteristics. J. Anim. Sci. 82 (Suppl 1.):116
- Silva, J. C., and L. W. Greene. 2004. Rate and extent of in situ DM disappearance of feedstuffs in cows fed different strains of yeast. Proc. Plains Nutr. Council Spring Conference. April 15-16, 2004. Publ. No. AREC 04-14. Texas A&M Research and Extension Center Amarillo. p. 112.
- Brown, M. S., L. W. Greene and N. A. Cole. 2004. Recent feedlot cattle research in the Texas Panhandle. Proc. Beef Cattle Short Course, TAMU.
- Cole, N. A., and L. W. Greene. 2004. Nutrient Management Considerations for Livestock Feeding Operations: Challenges and Opportunities. Proc. California Animal Nutrition Conference. May 5-6 2004 Fresno.
- Baumhardt, R. L., and L. W. Greene. 2004. Integrating cattle grazing into a dryland wheat sorghum fallow rotation. In: Rainwater, K. A. and Zobeck, T.M. eds. 2004. High Plains Groundwater Resources: Challenges and Opportunities. Conf. Proc., Texas Tech University Water Resources Center, Lubbock, TX.
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Progress 01/01/03 to 12/31/03
Outputs
The effects of different intakes of cations minus anions (DCAD) in heifers fed a roughage diet for 35 day on blood acid base characteristics and performance during the transition to a high concentrate diet were determined in 2 experiments. In experiment 1, 24 crossbred heifers (average initial weight = 245.5 kg), were blocked by weight and assigned to 3 DCAD diets, low, low+limestone and normal. The limestone in the low DCAD + limestone diet was only fed during the transition to the high concentrate diet. Low DCAD and low DCAD + limestone contained -99 mEq/kg and normal DCAD contained 247 mEq/kg of DM in the roughage diet calculated by mEq (Na+K+0.38Ca+0.3Mg)-(Cl+0.6S+0.5P). The low DCAD and low DCAD + limestone diets were prepared by the addition of ammonium chloride to the diet. The heifers fed low DCAD + limestone diet received 0.80% dietary limestone during the transition period to the high concentrate diet. By day 7 of feeding the anionic diets, urine pH was
lower (P < 0.05) for heifers fed low DCAD and low DCAD + limestone compared to those fed the normal DCAD diet. From day 21 to 35 urine pH for heifers fed low DCAD and low DCAD + limestone increased from 5.58 and 6.45 to 7.57 and 7.59, respectively. This response was presumably due to an increased ruminal fluid dilution rate caused by intake of added dietary salts. On day 10, 20 and 35 blood pH was lower (P < 0.05) for heifers fed low DCAD and low DCAD + limestone compared to those fed normal DCAD. During the transition period from day 36 to 53 heifers fed low DCAD + limestone consumed more (P < 0.05) feed. In experiment 2, heifers that were used in experiment 1 were fed a high roughage diet, reallocated to treatments on day 10, and provided the ammonium chloride in the drinking water instead of the diet to prevent a dilution by increased water intake. Low DCAD and low DCAD + limestone fed heifers were given ad libitum access to water containing ammonium chloride (0.007 kg/liter) for
17 days. By day 12, urine pH was lower (P < 0.05) for heifers fed low DCAD and low DCAD + limestone than for normal DCAD fed heifers and remained lower until day 20. On day 17, blood pH and HCO3- were lower (P < 0.05) for low DCAD and low DCAD + limestone fed heifers than for normal DCAD fed heifers. DMI during the transition to a high concentrate diet (day 18 to 33) was 8.07, 8.49 and 9.15 kg for low DCAD, low DCAD + limestone and normal DCAD, respectively (P=0.46). It required 5 days for the blood pH to return to normal after removal of the anionic salts to the diet.
Impacts
The data presented strongly suggest that preshipping dietary cation balance may be playing a critical role in the acid-base status of cattle being received in the feedyard. By starting cattle on high concentrate diets immediately after receiving may further exacerabate the negative acid base status and predispose these cattle to metabolic acidosis in the feedyard during the transition to high concentrate diets.
Publications
- Vasconcelos, J. T., L. W. Greene, F. T. McCollum, B. W. Bean and R. Van Meter. 2003. Performance of cross bred steers grazing photoperiod sensitive and non photoperiod sensitive Sorghum Sudangrass hybrids. Proc. Plains Nutr. Council Spring Conference. April 3-4, 2003. Publ. No. AREC 03-13. Texas A&M Research and Extension Center Amarillo. p. 119.
- White, M. B., G. E. Carstens, C. M. Theis, L. J. Slay, R. A Hollenbeck, T. H. Welsh, R. D. Randel, B. G. Warrington, T. D. A. Forbes, H. Lippke, L. W. Greene and D. K. Lunt. 2003 Proc. Plains Nutr. Council Spring Conference. April 3-4, 2003. Publ. No. AREC 03-13. Texas A&M Research and Extension Center Amarillo. p. 120.
- Hough, B., L. W. Greene, F. T. McCollum, B. W. Bean, N. A. Cole, and T. Montgomery. 2003. Performance of feedlot heifers fed corn silage or brown midrib forage sorghum silage as the roughage protion of a finishing diet. Proc. Amer. Soc. Anim. Sci. Midwestern Branch Annual meeting. p. 74.
- Williams, J. J. and L. W. Greene. 2003. Effects of metabolic acid-base disturbance caused by cation anion intake on performance of heifers before and during trasition to a hig concentrate finishing diet. Proc. Amer. Soc. Anim. Sci. Midwestern Branch Annual meeting. p. 75.
- Vasconcelos, J. T., L. W. Greene, F. T. McCollum, B. W. Bean, and R. Van Meter. 2003. Performance of crossbred steers grazing photoperiod sensitive and non photoperiod sensitive Sorghum Sudangrass hybrids. Proc. Amer. Soc. Anim. Sci. Midwestern Branch Annual meeting. p. 79.
- Vasconcelos, J. T., L.W. Greene, F. T. McCollum, B. W. Bean and R. VanMeter. 2003. Performance of crossbred steers grazing photoperiod sensitive and non photoperiod sensitive sorghum sudangrass hybrids. Beef Cattle Research in Texas 2002. p. 74
- Williams, J. J., and L. W. Greene. 2003. Effects of metabolic acid-base disturbance caused by fixed ion imbalance during the growing period on performance of beef cattle during transition to a high concentrate finishing diet. Beef Cattle Research in Texas 2002. p. 76
- Carstens, G. E., C. M. Theis, M. B. White, T. H. Welsh, Jr., B. G. Warrington, R. K. Miller, R. D. Randel, T. D. A. Forbes, H. Lippke, L. W. Greene and D. K. Lunt. 2003. Relationships between net feed intake and ultrasound measures of carcass composition in growing beef steers. Beef Cattle Research in Texas 2002. p. 31.
- Banta, J. P., F. T. McCollum, and L. W. Greene. 2003. Effects of Grazing a brown midrib vs. a normal sorghum X sudan hybrid on steer performance. Beef Cattle Research in Texas 2002. p. 18
- Banta, J. P., F. T. McCollum, L. W. Greene, K. W. McBride, G. Scaglia, J. J. Williams, B. Bean, and R. Van Meter. 2003. Performance of stocker cattle grazing a brown midrib sorghum X sudan hybrid in either a continuous or rotational grazing system. Beef Cattle Research in Texas 2002. p. 20.
- Scaglia, G., L. W. Greene, F. T. McCollum, N. A. Cole, and T. H. Montgomery. 2003. Effect of delaying implant and programmed rate of gain on performance and carcass characteristics of yearling beef steers. Prof. Anim. Sci. In press.
- Scaglia, G., L. W. Greene, F. T. McCollum, N. A. Cole, and T. H. Montgomery. 2004. Performance and carcass characteristics of feedlot steers following delayed implant and programmed feeding during the growing period. Prof. Anim. Sci. In press.
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Progress 01/01/02 to 12/31/02
Outputs
Dietary cation-anion difference (DCAD), is the difference in milliequivalents (mEq) of Na, Ca, Mg and K from Cl, P and S per kg of dry matter intake. The ratio of these charged particles in the diets of ruminants has been found to have an effect on productivity and acid-base balance. This study was conducted to determine the effect of anionic diets during the growing period on subsequent transition to a high concentrate diet. Twenty seven crossbred heifers, with an initial mean live weight of 236 kg were sorted by weight and randomly assigned within weight groupings to 3 pens and fed individually using Calan head gate feeders. Three experimental diets of containing -99, +72 and +247 mEq/kg were randomly assigned to each heifer within a pen (n=3 per pen) in a randomized block design. All heifers were maintained on a high fiber (60% soy bean hull pellet) diet for 70 d. To generate the +72 and - 99 DCAD diets, anions were added to the diet in the form of ammonium
chloride. All diets were isonitrogenous. Every week, the amount of feed offered was adjusted to maintain an estimated ADG of 0.91 kg for 70 d. From d 71 to 79 all heifers were transitioned to full feed. Beginning on d 80 the concentration of corn was increased at a rate of 10 percentage units of as fed intake every 3 d at the expense of cottonseed hulls until heifers were consuming 80% steam-flaked corn. Urine was collected at 0900 h on d 14, 28, 42, 56, 70, daily from 80 to 93, 96, 103 and 110 and tested for pH. Urine collection and pH testing time did not exceed 5 min for any heifer. Arterial blood samples were collected on d 28, 56, 70, 80, 96 and 110 for analysis of pCO2, and acid-base variables including blood pH and HCO3- concentration. Urine pH was reduced (P < 0.05) in heifers consuming the - 99 mEq/kg diet on d 14, 28, 42, 56, 70 and 80 compared to those fed the +72 and +247 mEq/kg diets. This response is indicative of a low metabolic pH. During d 70 to 80 urine pH for the -
99 mEq/kg fed heifers decreased (P < 0.05) from 7.06 to 6.11. This sudden additional reduction in urine pH was presumably due to the scheduled increase in dry matter intake that. Urine pH for the - 99 mEq/kg fed heifers remained lower (P < 0.05) for 4 d after the initiation of the transition to a high concentrate diet. Blood bicarbonate concentrations were not different on d 28, 56 or 70. However, on d 80 blood bicarbonate levels were lower (P < 0.05) for the heifers fed - 99 mEq/kg than for those fed +72 and +247 mEq/kg. On d 80 pCO2 was lower (P < 0.05) for the heifers fed - 99 mEq/kg than for those fed +247 and +72 mEq/kg. Dietary CAD did not affect dry matter intake from d 1 to 79 of phase I. However, dry matter intake was lower for the - 99 mEq/kg fed heifers than for the +72 mEq/kg fed heifers from d 80 to 110. From d 1 to 79 ADG was lower for heifers consuming - 99 mEq/kg than for heifers consuming +247 mEq/kg. From d 80 to 110 ADG was higher (P < 0.05) for the +72 mEq/kg fed
heifers than for those fed - 99 mEq/kg.
Impacts
This study indicates that cattle consuming anionic diets typical in some beef production areas may experience more acidosis when transitioning to high concentrate diets in the feedyard. These data will be useful in designing receiving diets to accomodate previous dietary cation/anion status of receiving cattle.
Publications
- Williams, J. J., and L. W. Greene. 2002. Effects of dietary cation anion blanace on blood parameters and performance characteristics of beef cattle during the pre-receiving and receiving phases of the feedlot. J. Anim. Sci. 80 (Suppl. 1): 273.
- Chirase, N. K., L. W. Greene, G. D. Graham and D. J. Smith. 2002. Effect of clostridial vaccines on performance, feed consumption patterns and lesion size scores of beef steers. Proc. Amer. Soc. Anim. Sci. Southern Section p. 7.
- Chirase, N. K., L. W. Greene, C. W. Purdy, R. W. Loan, T. H. Montgomery and J. A. Avampato. 2002 Effect of dietary antioxidant vitamins on carcass characteristics of beef steers exposed to cattle feedyard manure dust. Proc. Amer. Soc. Anim. Sci. Southern Section p. 7.
- Theis, C. M., G. E. Carstens, M. B. White, M. W. Kurz, C. Chen, T. H. Welsh, Jr., B. G. Warrington, R. D. Randel, T. D. A. Forbes, H. Lippke, L. W. Greene and D. K. Lunt. 2002. Relationship between net feed intake, performance traits and ultrasound measures of composition in beef steers. Proc. Plains Nutr. Council Spring Conference. April 25, 2002. Publ. No. AREC 02-20. Texas A&M Research and Extension Center Amarillo. p. 138.
- Greene, L. W. 2002. Uso de leveduras em bovines de corte. Proc. IV Simposio Goiano Sobre Manejo e Nutricao de Bovinos de Corte. May, 2002.
- Han, H., H. S. Hussein, H. A. Glimp, D. H. Saylor and L. W. Greene. 2002. Carbohydrate fermentation and nitrogen metabolism of a finishing beef diet by ruminant microbes in continuous cultures as affected by ethoxyquin and (or) supplementation of monensin and tylosin. J. Anim. Sci. 80:1117-23
- Moya, J.R., C. E. Coppock, L. W. Greene and D. H. Nave. 2002. Influence of energy level changes on in vitro rumen pH and microbial populations. Puerto Rico J. Dairy Sci.: submitted.
- Greene, L. W., K. Xie and D. K. Lunt. 2002. Magnesium, Calcium and Phosphorus Status of Cows Grazing Ammonium Sulfate Fertilized Pastures. J. Anim. Vet. Adv. 1:12-15.
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Progress 01/01/01 to 12/31/01
Outputs
Cattle arriving at Southern High Plains feedyards from Eastern New Mexico and West Texas have been identified to have a higher medicine cost than cattle arriving from the South Eastern United States. When these cattle become morbid, it is usually within 20 days of arrival at the feedyard. Our laboratory has evaluated the nutrient supply from these areas and found that water from the affected areas are usually higher in sulfate. Adding sulfate to the diet will decrease the dietary cation anion difference (DCAD). DCAD has been shown to have and effect on both health and individual productivity during intense production situations. Shifting animals from a high roughage diet in the presence of a low DCAD environment to a high concentrate diet upon arrival at the feedyard, may subject these cattle to a greater risk of metabolic disorders such as acidosis. Research involving the effect of DCAD on the performance and overall health of beef cattle during the initial stages of
adaptation to a high concentrate diet has not been conducted. Therefore, the objective of this research was to determine the effects of DCAD in growing cattle on subsequent performance and metabolic pH when starting onto high concentrate diets. Twenty seven crossbred heifers were used for the study. Heifers were housed in 3 pens containing 9 electronic calan gates per pen. Cattle were trained to use the calan gates over a 2 week adaptation period. After training, cattle were fed a diet for a targeted growth of .91 kg/day. Each diet was isonitrogenous and isocaloric. The diets were formulated to contain either -100, +75, or +250 mEq/kg DCAD levels. The diets were fed for an 80-day diet adaptation period. On day 80, cattle were started on a high concentrate diet over a 20-day period. Urine pH were measured at 3 day intervals on each heifer. Blood pH was determined at six times during the experiment. Urine pH was lower (P < .05) for the -100 mEq/kg diet than the +75 or +250 mEq/kg
diets at the end of the adaptation period. Urine pH remained lower during the first six days of the diet step-up period. Differences in blood pH and white blood cell counts were not different. None of the cattle used in this experiment were considered acidotic during the diet step-up period. A second experiment is being conducted with a more aggressive diet step-up period to determine if cattle entering the feedyard with a lower pH status (urine pH) will be more susceptible to acidosis during the diet step-up period.
Impacts
Developing prescription feeding programs for cattle arriving at the nations feedyards from areas of the country that are more prone for producing morbid cattle will improve the production efficiency of these operations.
Publications
- Greene, L. W. and C. R. Richardson. 2001. Use of trans Texas video network for graduate education between Texas A&M University System and Texas Tech University. J. Anim. Sci. 79 (Suppl. 1):124.
- Scaglia, G., J. J. Williams, L. W. Greene and N. A. Cole. 2001. Ruminal and degradability of different feeds in the presence of Saccharmoyces cervisiae. J. Anim. Sci. 79 (Suppl. 1): 285.
- Williams, J. J., G. Scaglia, and L. W. Greene. 2001. Effects of live yeast concentrates on the in vitro semi-continuous culture fermentation of a high concentrate diet. J. Anim. Sci. 79 (Suppl. 1): 286.
- Greene, L. W., F. T. McCollum, III, N. K. Chirase, and T. M. Montgomery. 2001. Performance and conservation of phosphorus in growing cattle. J. Anim. Sci. 79 (Suppl. 1): 293.
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Progress 01/01/00 to 12/31/00
Outputs
A growing study using 144 growing crossbred heifers was conducted to determine the effect of decreasing level of dietary phosphorus and brewers grain yeast on phosphorus excretion. Heifers weighed approximately 213 kg at the beginning of the study. Upon arrival cattle were weighed, vaccinated and treated for shipping stress if necessary. Cattle were maintained in a 45 day receiving period before the initiation of the study. At the beginning of the study cattle were allotted to 12 fly-ash floored pens designed for sampling total water runoff during rain events. Pens were cleaned of all manure prior to the initiation of the 103 d study. Two levels of dietary phosphorus (.22 or .33%) and two levels of dietary brewers' grain yeast (0 or .1 kg/d) was assigned to cattle in each pen in a 2 X 2 factorial arrangement of treatments. The diets were fed to provide .9 kg of daily gain per head throughout the growing period. Intake of each diet was increased at 2 week intervals to
maintain the desired gain. At the conclusion of the experiment, final weighs were obtained and pens cleaned of all manure. Manure was weighed, sampled and analyzed for nitrogen and phosphorus. There was no interaction between brewers' grain yeast and phosphorus level. Therefore data are summarized across main effects. Cattle fed brewers' grain yeast had greater (P = .014) average daily gains compared to those fed the control diet (1.0 vs. .93 kg/d). There was no difference in the utilization of nitrogen or phosphorus when brewers' grain yeast was included in the diet. Formulating the diet to contain 33% less phosphorus did not result in any reduction in performance of cattle (P < .10). However, cattle fed diets formulated to contain .22% P excreted less manure (P < .0270) than those fed the diets containing .33% phosphorus. This reduction is probably due to less cottonseed hulls, and more soybean hulls and fat fed in the .22% phosphorus diet compared to the .33% phosphorous diet. Pen
surface phosphorus decreased from 1.65 kg to 1.05 kg per animal over the 103 d experiment when the lower phosphorus diet was fed. Using manure phosphorus as a standard, feeding 0.22% vs 0.33% dietary phosphorus to cattle in growing/backgrounding yards can reduce the acreage needed for proper manure utilization by approximately 226 acres for an average size (4,000 head capacity) growing/backgrounding yard.
Impacts
Research conducted by researchers at Texas A&M University Agricultural Research and Extension Center at Amarillo shows that reducing the dietary concentration of phosphorus from normally used levels of 0.33% to 0.22% in growing/backgrounding cattle diets can significantly reduce the acreage needed for manure disposal. Research was conducted at the Texas Agricultural Experiment Station/United States Department of Agriculture - Agricultural Research Service experimental feedlot at Bushland, Texas
Publications
- Greene, L.W. 2000. Designing mineral supplements for beef cattle. J. Anim. Sci. 78: Electronic Publication.
- Greene, L.W. and J.E. Huston. 2000. Copper toxicosis in sheep: A review. Sheep and Goat Research. J. 15:120-125.
- McBride, K. W., L. W. Greene, N. K. Chirase and E. B. Kegley. 2000. The effects of Agrado on the performance and antioxidant status of feedlot steers. Proceedings Plains Nutrition Council Spring Conference Pub. No. AREC-00-22 Texas A&M University Research and Extension Center, Amarillo, p. 85.
- George, D. R., N. K. Chirase, L. W. Greene and F. T. McCollum. 2000. Effects of implanting growing steers grazing short grass prairie pastures on subsequent feedyard excretion of P and N, animal performance, and carcass characteristics. . Proceedings Plains Nutrition Council Spring Conference Pub. No. AREC-00-22 Texas A&M University Research and Extension Center, Amarillo, p. 80
- Greene, L.W. and N.K. Chirase. 2000. Mineral nutrition for optimum reproduction efficiency of beef cattle. Proceedings Reproductive Efficiency in Beef Cattle Symposium. Parkins Whitaker Animal Science Center Univ. of Ark. March 31, 2000. p. 1-6.
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