Progress 10/01/01 to 09/30/07
Outputs
OUTPUTS: When feeding protein supplements to prepartum range cows, urea inclusion at less than 15% of ruminally degradable protein (RDP) was compatible with less-frequent supplementation. Due to supplement refusal, caution should be used in feeding more urea at infrequent intervals. Urea recycling helps cattle salvage N that would otherwise be excreted. In cattle fed low-protein forage, urea recycled to the rumen and subsequently used by ruminal microbes increased linearly with supplementation of either RDP or ruminally undegradable protein (RUP). For cattle receiving RDP, almost all urea produced by the body was recycled to the gut, and about 60% of this was captured and used by ruminal microbes; recycled urea accounted for about 28% of the N used by ruminal microbes. For cattle supplemented with RUP, almost all urea produced by the body was recycled to the gut, but recycled urea accounted for an increasing proportion of N used by ruminal microbes as protein supplementation
increased. The proportion of supplemental N used by ruminal microbes was greater when RUP was supplied than RDP, reflecting that the microbes did not have access to the protein from RUP until it was recycled. When low amounts of RDP were supplemented daily or every third day, urea recycled to the gut was not affected by frequency of supplementation. When large amounts of protein were supplemented daily or every third day, urea recycled to the gut was greater with less frequent supplementation, but overall efficiency of N capture by the rumen was decreased with less frequent supplementation. Although urea recycling improves protein status of cattle, it cannot completely overcome inefficiencies induced by infrequent supplementation. Effects of protein status on histidine use was evaluated in cattle. Increases in ruminal ammonia did not affect nitrogen (N) retention, independent of histidine status. Excess amino acids (AA) increased protein deposition when histidine was limiting, likely
a response to increased energy supply. Efficiency of histidine use was greater when excess AA were provided, demonstrating that nutritional factors impact efficiency of histidine use. Efficiency of histidine use averaged 64%, close to that used in various models. Although excess protein is not environmentally friendly, it did not penalize animal growth. Energy supplementation improved leucine use by modestly increasing N retention when leucine was limiting, indicating that energy supply affects efficiency of leucine use. Efficiency of leucine use was less than predicted by most models. The assumption of a constant efficiency of AA use is unlikely correct in growing steers, and models of AA requirements in cattle should consider dietary energy supply. Responses to energy by cattle limited by leucine were less than those observed for cattle limited by methionine, suggesting that the effect of energy on efficiency of AA use may differ among AA. The effects of ractopamine were tested in
heifers fed diets providing different amounts of metabolizable protein. Increasing the dietary protein supply was not necessary to obtain maximal performance of heifers whether heifers received ractopamine or not.
PARTICIPANTS: Evan C. Titgemeyer - Principle investigator Bradley J. Johnson - Principle investigator Robert C. Cochran - Principle investigator
TARGET AUDIENCES: Beef cattle industry, including all phases relating to cow-calf, growing cattle, and feedlot cattle Dairy cattle industry
Impacts
As a whole, these projects were designed to improve our ability to match animal requirements with nutrient supply from the diet. By better predicting 1) animal requirements, 2) animal response to exogenous growth promoting agents, and 3) availability of nutrients from different feedstuffs, we can better supplement cattle diets to optimize nutrient and economic efficiency and to reduce the excretion of waste nitrogen into the environment. Research exploring levels of urea inclusion in high-protein supplements indicated that a small amount of urea can be substituted for degradable true protein in supplements fed to cattle eating low-quality forage without negatively affecting forage intake or digestion. Similarly, substituting a limited amount of urea for ruminally degradable protein during the prepartum period does not significantly alter body weight or condition change. However, at higher levels of urea inclusion, supplement unacceptability and reduced performance can
occur. For prepartum supplementation of pregnant beef cows, it seems advisable to avoid exceeding 40% of the supplemental nitrogen in the ruminally degradable protein from urea. Up to 15% of the ruminally available protein in a protein supplement can be provided as urea without a penalty to the performance of prepartum cows grazing poor quality forage; this is true whether supplements are provided daily or less frequently. Data from studies with amino acid requirements demonstrate that 1) amino acid utilization varies among amino acids, and it is generally lower than suggested by some models of nutrient utilization, 2) amino acid use is generally improved by energy supply, although the magnitude of this response varies among amino acids, and 3) excess protein provided to cattle does not appear to have a negative impact on amino acid use. This information can be used to improve predictions of amino acid requirements of growing cattle. Although excess dietary protein is not
environmentally friendly, it does not appear to directly penalize animal growth. Our projects with urea recycling provide data that can be used in predictive models to determine the amount and type of dietary protein that must be supplemented to meet the needs of ruminal microbes for available nitrogen. Although qualitative information related to urea recycling has been available for years, only recently have more quantitative numbers been available to allow incorporation into predictive models. Our data comparing urea recycling when forage-fed cattle are fed either ruminally degradable protein or ruminally undegradable protein will be helpful in predicting the amount of supplemental dietary protein that is needed to meet animal requirements. Overall, data will be used to better formulate diets to meet the protein needs of cattle while minimizing cost and environmental excretion of nitrogen.
Publications
- Elwakeel, E.A., E.C. Titgemeyer, J.S. Drouillard, and C.K. Armendariz. 2007. Evaluation of ruminal nitrogen availability in liquid feeds. Anim. Feed Sci. Technol. 137:163-181.
- Walker, D.K., E.C. Titgemeyer, E.K. Sissom, K. R. Brown, J. J. Higgins, and B.J. Johnson. 2007. Effects of steroidal implantation and ractopamine-HCl on nitrogen retention, blood metabolites, and longissimus mRNA expression of IGF-I in Holstein steers. J. Anim. Physiol. Anim. Nutr. 91:439-447.
- Awawdeh, M.S., E.C. Titgemeyer, J.S. Drouillard, R.S. Beyer, and J.E. Shirley. 2007. Ruminal degradability and lysine bioavailability of soybean meals and effects on performance of dairy cows. J. Dairy Sci. 90:4740-4753.
- Schroeder, G.F., E.C. Titgemeyer, and E.S. Moore. 2007. Effects of energy supply on leucine utilization by growing steers at two body weights. J. Anim. Sci. 85:3348-3354.
- Wickersham, T.A. E.C. Titgemeyer, R.C. Cochran, and E.E. Wickersham. 2007. Supplementation with undegradable intake protein increases utilization of low-quality forage and microbial use of recycled urea. Beef Cattle Research. Report of Progress 978, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 85-87.
- Schroeder, G.F., E.C. Titgemeyer, and E.S. Moore. 2007. Energy supply affects leucine utilization by growing steers. Beef Cattle Research. Report of Progress 978, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 46-48.
- Wickersham, T.A., E.C. Titgemeyer, R.C. Cochran, E.E. Wickersham, and D.P. Gnad. 2007. Supplementation with degradable intake protein increases low-quality forage utilization and microbial use of recycled urea. Beef Cattle Research. Report of Progress 978, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 79-81.
- Wickersham, T.A., E.C. Titgemeyer, R.C. Cochran, E.E. Wickersham, and E.S. Moore. 2007. Microbial use of recycled urea is dependent on the level and frequency of degradable intake protein supplementation. Beef Cattle Research. Report of Progress 978, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 82-84.
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Progress 01/01/06 to 12/31/06
Outputs
Nitrogen recycling helps cattle to deal with deficiencies in dietary protein by salvaging nitrogen that would otherwise be excreted. Studies measured recycling in cattle fed low-protein forage and supplemented with different amounts and types of protein. Urea recycled to the rumen and subsequently used by ruminal microbes increased linearly with supplementation of either ruminally degradable protein (RDP) or ruminally undegradable protein (RUP). For cattle receiving RDP, almost all of the urea produced by the body was recycled to the gut, and about 60% of this was captured and used by the ruminal microbes; recycled urea accounted for about 28% of the nitrogen utilized by ruminal microbes. For cattle supplemented with RUP, almost all of the urea produced by the body was recycled to the gut, but recycled urea accounted for an increasing proportion of the nitrogen utilized by ruminal microbes as protein supplementation increased. The proportion of supplemental nitrogen
utilized by ruminal microbes was greater when RUP was supplied than when RDP was supplied, reflecting that the microbes did not have access to the protein from RUP until it was first recycled. In contrast, when RDP was supplemented, the ruminal microbes could benefit from the supplementation both directly as well as indirectly as a result of urea recycling. When low amounts of RDP were supplemented daily or every third day, the amount of urea recycled to the gut was not affected by frequency of supplementation. When large amounts of protein were supplemented daily or every third day, the amount of urea recycled to the gut was greater with less frequent supplementation, but overall efficiency of nitrogen capture by the rumen was decreased with less frequent supplementation. Thus, although urea recycling helped to improve the protein status of cattle, it was not able to completely overcome inefficiencies induced by infrequent supplementation of large amounts of protein. The effects of
energy supply on leucine utilization were evaluated in growing steers at two body weights. For steers with initial body weights of 150 kg, energy supplementation improved leucine utilization by increasing the ability of steers to respond to the greatest amount of supplemental leucine and by modestly increasing nitrogen retention when leucine was limiting, indicating that energy supplementation improved the efficiency of leucine utilization. For steers initially weighing 275 kg, nitrogen retention was not affected by leucine supply, indicating that leucine did not limit protein deposition, but energy increased nitrogen retention independent of leucine supply. Results indicate that the assumption of a constant efficiency of amino acid utilization is unlikely to be appropriate in growing steers, and therefore modeling of amino acid requirements in growing cattle may require consideration of the amount of dietary energy supplied. Responses to energy by cattle limited by leucine were less
than those observed previously for cattle limited by methionine, suggesting that the magnitude of the effect of energy on efficiency of amino acid use may differ among amino acids.
Impacts
These data will improve our ability to match animal requirements to nutrient supply from the diet. Our projects with urea recycling provide data that can be used in predictive models to determine the amount and type of dietary protein that must be supplemented to meet the needs of ruminal microbes for available nitrogen. Our projects with amino acid utilization will allow better estimates of amino acid requirements of growing cattle. We observed that utilization of amino acids for protein deposition by cattle is affected by the energy supply, so prediction of animal requirements will require models more complex than those currently available. More data will be needed to validate predictive models before they can be used by the cattle industry.
Publications
- Villarreal, M., R.C. Cochran, A. Rojas-Bourrillon, O. Murillo, H. Munoz, and M. Poore. 2006. Effect of supplementation with pelleted citrus pulp on digestibility and intake in beef cattle fed a tropical grass-based diet (Cynodon nlemfuensis). Anim. Feed Sci. Technol. 125:163-173.
- Llewellyn, D.A., R.C. Cochran, T.T. Marston, D.M. Grieger, C.G. Farmer, and T.A. Wickersham. 2006. Influence of limited fall protein supplementation on performance and forage utilization by beef cattle grazing low-quality native grass pastures. Anim. Feed Sci. Technol. 127:234-250.
- Walker, D.K., E.C. Titgemeyer, J.S. Drouillard, E.R. Loe, B.E. Depenbusch, and A.S. Webb. 2006. Effects of ractopamine and protein source on growth performance and carcass characteristics of feedlot heifers. J. Anim. Sci. 84:2795-2800.
- Schroeder, G.A., E.C. Titgemeyer, and E.S. Moore. 2006. Effects of energy supplementation on leucine utilization by growing steers. J. Anim. Sci. 84(Suppl. 1):456.
- Wickersham, T.A., E.C. Titgemeyer, R.C. Cochran, and E.E. Wickersham. 2006. The effect of degradable intake protein on urea kinetics in steers consuming low-quality forage. J. Anim. Sci. 84(Suppl. 1):456-457.
- Wickersham, T.A., E.C. Titgemeyer, R.C. Cochran. 2006. Determining the proportion of urea recycled to the gut that is incorporated into ruminal microbial protein. J. Anim. Sci. 84(Suppl. 1):457.
- Walker, D.K., E.C. Titgemeyer, J.J. Higgins, and B.J. Johnson. 2006. An investigation into the mechanisms of action of Revalor-S and Optaflexx in growing steers. Beef Cattle Research. Report of Progress 959, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 15-19.
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Progress 01/01/05 to 12/31/05
Outputs
Nitrogen recycling plays an important role in the ability of cattle to digest feedstuffs in situations where the protein concentration in the diet is particularly low. By measuring the impact of nutrient modifications on nitrogen recycling, we should be able to better predict cattle requirements for dietary crude protein and thereby better formulate diets to match nutrient intakes with nutrient requirements. Studies were undertaken to quantify urea recycling in beef cattle fed forage-based diets. These studies evaluated the impact of various protein supplementation strategies with the use of isotopically labeled urea. Our methodologies should extend our knowledge of urea recycling specifically by partitioning the urea recycling to different segments of the gastrointestinal tract such that the impact of supplementation on the portion of recycled urea used for productive purposes can be measured. Laboratory work is currently underway for these projects, and results are
pending. An experiment was conducted to evaluate mechanisms by which steroidal implants and beta-agonists work to increase lean tissue growth in growing cattle. This experiment quantified nitrogen balance responses in growing steers given trenbolone acetate/estradiol implants and supplemented with ractopamine in the diet. As expected, serum concentrations of IGF-I and longissimus concentrations of mRNA for IGF-I were increased by implantation. In contrast, these two measures were decreased by ractopamine, which suggests that these two growth promoting agents work through different mechanisms. In spite of the differences in mechanism, however, nitrogen retention, a measure of lean tissue deposition, was improved less by ractopamine in the implanted steers than in the control steers, demonstrating that the response from combining the two growth promotants was less than additive. Future work will be needed to study the interactions between these two growth promotants.
Impacts
These projects are designed to improve our ability to match animal requirements with nutrient supply from the diet. By better predicting 1) animal requirements, 2) animal response to exogenous growth promoting agents, and 3) availability of nutrients from different feedstuffs, we should be able to better supplement cattle diets to optimize nutrient and economic efficiency and to reduce the excretion of waste nitrogen into the environment. Further work will be needed before recommendations can be applied to the cattle industry, but data from these trials will allow us to move forward with future research projects that will more directly address these issues.
Publications
- Bindel, D. J., E. C. Titgemeyer, J. S. Drouillard, and S. E. Ives. 2005. Effects of choline on blood metabolites associated with lipid metabolism and digestion in steers fed corn-based diets. J. Anim. Sci. 83:1625-1632.
- Villarreal, M., R.C. Cochran, A. Rojas-Bourrillon, O. Murillo, H. Munoz, and M. Poore. 2005. Effect of supplementation with pelleted citrus pulp on digestibility and intake in beef cattle fed a tropical grass-based diet (Cynodon nlemfuensis). Anim. Feed Sci. Technol. (in press).
- Llewellyn, D.A., R.C. Cochran, T.T. Marston, D.M. Grieger, C.G. Farmer, and T.A. Wickersham. 2005. Influence of limited fall protein supplementation on performance and forage utilization by beef cattle grazing low-quality native grass pastures. Anim. Feed Sci. Technol. (in press).
- Walker, D.K., E.C. Titgemeyer, J.S. Drouillard, E.R. Loe, B.E. Depenbusch, and A.S. Webb. 2005. Response of heifers fed Optaflexx(trademark) to supplemental protein. Beef Cattle Research. Report of Progress 943, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 11-14.
- Walker, D.K., E.C. Titgemeyer, B.J. Johnson, and J.J. Higgins. 2005. Effects of ractopamine and steroidal implantation on nitrogen retention and blood metabolites in Holstein steers. J. Anim. Sci. 83(Suppl. 1):114.
- Arroquy, J.I., R.C. Cochran, T.G. Nagaraja, E.C. Titgemeyer, D.E. Johnson. 2005. Effect of types of non-fiber carbohydrate on in vitro forage fiber digestion of low-quality grass hay. Anim. Feed Sci. Tech. 120:93-106.
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Progress 01/01/04 to 12/31/04
Outputs
Initial work was conducted to evaluate methodologies for measuring nitrogen recycling in forage-fed cattle. Nitrogen recycling plays an important role in the ability of cattle to digest feedstuffs in situations where the protein concentration in the diet is particularly low. By measuring the impact of nutrient modifications on nitrogen recycling, we should be able to better predict cattle requirements for dietary crude protein and thereby better formulate diets to match nutrient intakes with nutrient requirements. This initial study was conducted to validate the use of isotopically labeled urea and to verify the length of experimental periods needed to measure urea recycling in steers. Methodologies developed herein will be used in future studies to investigate the effects of nutrient supplementation strategies on nitrogen recycling in cattle. Studies were also conducted to evaluate methodologies for determining the ruminal availability of nitrogen from liquid feeds.
Previous methods did not work well for evaluating soluble proteins. The assay measures the growth of ruminal microbes in a model system where protein supply is limiting. Thus, microbial growth is directly related to the availability of protein from the test feeds. Several processing characteristics (heat, mineral additions, and storage time) were found to have significant impacts on protein availability. This method should be useful in improving our ability to match animal requirements with the supply for various feedstuffs that have been poorly characterized heretofore. An initial experiment was also conducted to evaluate mechanisms by which steroidal implants and beta-agonists work to increase lean tissue growth in growing cattle. This experiment was designed to quantify nitrogen balance responses in growing steers given trenbolone acetate/estradiol implants and supplemented with ractopamine in the diet. The initial data will demonstrate the magnitude and duration of the response to
ractopamine and allow us to efficiently design future experiments to study responses to beta-agonists in more detail. It is unknown if the dietary protein requirements of cattle provided with aggressive growth promoting agents is increased by these efforts to increase lean tissue growth rates. A study was conducted with implanted (trenbolone acetate plus estradiol) heifers. The effects of providing a beta-agonist, ractopamine, were tested when heifers were fed three diets providing different amounts of metabolizable protein to the heifers. The data demonstrated that increasing the dietary protein supply was not necessary to obtain maximal performance of heifers whether heifers received ractopamine or not.
Impacts
The need for supplemental protein increases as season advances during the fall period. Providing supplemental protein to cattle grazing native range during this period can improve diet digestibility. Although excess dietary protein is not economically efficient or environmentally friendly, excess dietary protein does not appear to directly penalize animal growth.
Publications
- Titgemeyer, E.C., J.S. Drouillard, R.H. Greenwood, J.W. Ringler, D.J. Bindel, R.D. Hunter, and T. Nutsch. 2004. Effect of forage quality on digestion and performance responses of cattle to supplementation with cooked molasses blocks. J. Anim. Sci. 82:487-494.
- McCuistion, K.C., E.C. Titgemeyer, M.S. Awawdeh, and D.P. Gnad. 2004. Histidine utilization by growing steers is not negatively affected by increased supply of either ammonia or amino acids. J. Anim. Sci. 82:759-769.
- Farmer, C.G., B.C. Woods, R.C. Cochran, J.S. Heldt, C.P. Mathis, K.C. Olson, E.C. Titgemeyer, and T. A. Wickersham . 2004. Effect of supplementation frequency and supplemental urea level on dormant tallgrass-prairie hay intake and digestion by beef steers and prepartum performance of beef cows grazing dormant tallgrass-prairie J. Anim Sci. 82:884-894.
- Farmer, C.G., R.C. Cochran, T.G. Nagaraja, E.C. Titgemeyer, D.E. Johnson, and T.A. Wickersham. 2004. Ruminal and host adaptations to changes in frequency of protein supplementation. J. Anim Sci. 82:895-903.
- Wickersham, T.A., R.C. Cochran, E.C. Titgemeyer, C.G. Farmer, E.A. Klevesahl, J.I. Arroquy, D.E. Johnson, and D.P. Gnad. 2004. Effect of postruminal protein supply on the response to ruminal protein supplementation in beef steers fed a low-quality grass hay. Anim. Feed Sci. Technol. 115:19-36.
- Arroquy, J.I., R.C. Cochran, M. Villarreal, T.A. Wickersham, D.A. Llewellyn, E.C. Titgemeyer, T.G. Nagaraja, D.E. Johnson, and D. Gnad. 2004. Effect of level of rumen degradable protein and type of supplemental non-fiber carbohydrate on intake and digestion of low-quality grass hay by beef cattle. Anim. Feed Sci. Technol. 115:83-99.
- Arroquy, J.I., R.C. Cochran, T.A. Wickersham, D.A. Llewellyn, E.C. Titgemeyer, T.G. Nagaraja, and D.E. Johnson. 2004. Effects of type of supplemental carbohydrate and source of supplemental rumen degradable protein on low-quality forage utilization by beef steers. Anim. Feed Sci. Technol. 115:247-263.
- Lambert, B.D., E. C. Titgemeyer, C. A. Loest, and D. E. Johnson. 2004. Effect of glycine and vitamin supplementation on sulphur amino acid utilization by growing cattle. J. Anim. Physiol. Anim. Nutr. (Berl.) 88:288-300.
- Elwakeel, E.A., E.C. Titgemeyer, and J.S. Drouillard. 2004. Evaluation of nitrogen availability in liquid feedstuffs. 2004 Cattlemen's Day, Report of Progress 923, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 33-36.
- Elwakeel, E.A. 2004. Evaluation of ruminal nitrogen availability in liquid feeds and in vitro evaluation of fibrolytic enzymes for dairy feedstuffs. M.S. Thesis, Kansas State University, Manhattan.
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Progress 01/01/03 to 12/31/03
Outputs
Research was conducted to evaluate the effect on forage utilization of providing a limited quantity of a high-protein (45.5% CP, DM basis) supplement to beef cattle grazing tallgrass-prairie during the fall period. Sixteen ruminally fistulated Hereford x Angus steers (BW = 259 kg) were used in a two-treatment (i.e., fall supplementation vs no fall supplementation), two-period (i.e., September vs November) study. Steers were individually fed the high-protein supplement at a rate of 0.14% of BW/d (as-fed basis) but prorated and delivered 3 d/wk. The effect of fall supplementation on diet selection, intake, and digestion was not dependent on the period in which the characteristics were measured. The quality of diet selected decreased as season progressed (crude protein decreased and forage fiber increased) and, as a result, digestible organic matter intake and total tract organic matter digestion were lower (P=0.04 and P=0.02, respectively) during November. Fall
supplementation did not significantly influence the quality of diet selected or forage intake but supplemented steers tended (P = 0.06) to digest their diet to a greater extent. In another study, we evaluated the effects of excess amino acid supply on histidine utilization by 150-kg Holstein steers. The trial was a 6 x 6Latin square with abomasally infused treatments arranged as 3 x 2 factorial: 0 or 1 g/d of L-histidine in combination with no additional amino acids (Control), 100 g/d of essential + 100 g/d of non-essential amino acids (NEAA+EAA), or 200 g/d of essential amino acids (EAA). Retained N increased (P < 0.05) from 34.2 to 38.3 g/d in response to histidine. Supplementation with NEAA+EAA increased (P < 0.05) N retention (33.9, 39.3, and 35.6 g/d for Control, NEAA+EAA, and EAA, respectively), likely a response to increased energy supply. The lack of response for steers on the EAA treatment may be a result of a methionine imbalance, which may have moderated responses to the
energy provided by the EAA treatment. Plasma methionine concentrations were extremely high for the EAA treatment, which reflects the imbalance. The responses in N retention to histidine were numerically greater for the NEAA+EAA and EAA treatments than for Control (i.e., increases of N retention in response to histidine of 3.6 and 6.3 g/d vs 2.3 g/d), which suggest that nutritional factors do impact how efficiently amino acids (at least histidine) are used, but further work will be needed before these variables can be incorporated into protein models used for predicting animal performance. Incremental histidine efficiency averaged 63% over the treatments (36%, 56%, and 98% for Control, NEAA+EAA, and EAA, respectively), a value similar to the 71% value predicted by NRC equations. Under our experimental conditions, increases in amino acid supply did not demonstrate a metabolic cost in terms of histidine utilization for whole body protein deposition by growing steers.
Impacts
The need for supplemental protein increases as season advances during the fall period. Providing supplemental protein to cattle grazing native range during this period can improve diet digestibility. Although excess dietary protein is not economically efficient or environmentally friendly, excess dietary protein does not appear to directly penalize animal growth.
Publications
- Candler, K.C., E.C. Titgemeyer, M.S. Awawdeh, and D.P. Gnad. 2003. Ruminal ammonia load does not affect histidine utilization in growing steers. Report of Progress 908, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 196-198.
- Candler, K.C., E.C. Titgemeyer, M.S. Awawdeh, and D.P. Gnad. 2003. Ruminal ammonia load does not impact histidine utilization by growing steers. J. Anim. Sci. 81(Suppl. 2):68.
- Llewellyn, D.A., R.C. Cochran, T.T. Marston, D.M. Grieger, C.G. Farmer, and T.A. Wickersham. 2003. Effect of low-level fall protein supplementation on the performance of beef cows grazing tallgrass-prairie range. J. Anim. Sci. 81(Suppl. 2):101.
- Llewellyn, D.A., R.C. Cochran, T.T. Marston, C.G. Farmer, and T.A. Wickersham. 2003. Influence of low-level protein supplementation on forage intake, diet digestion and selection by beef steers grazing tallgrass-prairie range during the fall. J. Anim. Sci. 81(Suppl. 1):332-333.
- Llewellyn, D.A., R.C. Cochran, T.T. Marston, D.M. Grieger, C.G. Farmer, T.A. Wickersham, and D.D. Simms. 2003. Influence of low-level supplementation with a high-protein feed on performance of beef cows grazing tallgrass-prairie range during the fall. AES and CES Report of Progress 908, Kansas State University, Manhattan, pp. 137-142.
- Llewellyn, D.A., R.C. Cochran, T.T. Marston, C.G. Farmer, and T.A. Wickersham. 2003. Influence of low-level fall protein supplementation on forage intake, diet digestion, and selection by beef steers grazing tallgrass-prairie. AES and CES Report of Progress 908, Kansas State University, Manhattan, pp. 143-146.
- McCuistion, K.C. 2003. Factors affecting histidine utilization in growing steers. M.S. thesis, Kansas State University, Manhattan.
- Trater, A.M., E.C. Titgemeyer, J.S. Drouillard, and J.N. Pike. 2003. Effects of processing factors on in vitro ammonia release from cooked molasses blocks containing urea. Anim. Feed Sci. Technol. 107:173-190.
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Progress 01/01/02 to 12/31/02
Outputs
Research exploring levels of urea inclusion in high-protein supplements indicated that a small amount of urea can be substituted for degradable true protein in supplements fed to cattle eating low-quality forage without negatively affecting forage intake or digestion. Similarly, substituting a limited amount of urea for ruminally degradable protein during the prepartum period does not significantly alter body weight or condition change. However, at higher levels of urea inclusion, supplement unacceptability and reduced performance can occur. For prepartum supplementation of pregnant beef cows, it seems advisable to avoid exceeding 40% of the supplemental N in the ruminally degradable protein from urea. Results from an experiment examining the interaction between frequency of feeding and urea inclusion in supplements indicated that when feeding high protein supplements (e.g., 40% CP) to prepartum range cows, low-level urea inclusion (less than or equal to 15% of
ruminally degradable protein from urea) is compatible with less-frequent supplementation. However, because of supplement refusal and associated negative performance responses, caution should be exercised in feeding higher protein supplements with higher levels of urea (greater than 15% of ruminally degradable protein from urea) at less frequent intervals (e.g., 2 or 3 d/wk). Field data collection is complete from an experiment exploring the impact of low-level, high-protein supplementation during the fall period on forage use and performance. Data summarization will occur once lab analyses are completed. In a final area of investigation, we evaluated the effects of rumen ammonia load on histidine utilization. Fermentation of dietary protein in the rumen leads to increased ammonia absorption which could impair amino acid utilization in cattle. Six ruminally cannulated Holstein steers were used in a Latin square design. Treatments were arranged as a 3 x 2 factorial and included: 0, 1.5,
or 3 grams/day L-histidine infused abomasally; and 0 or 80 grams/day urea infused ruminally to supply a metabolic ammonia load. As expected, urea infusions increased rumen ammonia and plasma urea concentrations. No change in nitrogen retention, a measure of lean tissue growth, occurred in response to urea. Retained nitrogen increased with histidine supply, and the maximal response occurred with 1.5 grams/day of histidine, suggesting that this amount was near the supplemental requirement. Efficiency of deposition of supplemental histidine between 0 and 1.5 grams/day was 65%, which is relatively close to the value utilized in various models of nutrient utilization. Our research revealed that increases in ammonia load did not demonstrate a metabolic cost in terms of whole body protein deposition, regardless of whether histidine was limiting. Thus, although an excess protein supply may not be economically efficient or environmentally friendly, it does not appear to directly penalize
animal performance.
Impacts
Up to 15% of the ruminally available protein in a protein supplement can be provided as urea without a penalty to the performance of prepartum cows grazing poor quality forage; this is true whether supplements are provided daily or less frequently. Ammonia, a product of excess dietary protein, does not have a detrimental impact on lean deposition in growing cattle under our research conditions.
Publications
- Koster, H.H., B.C. Woods, R.C. Cochran, E.S. Vanzant, E.C. Titgemeyer, D.M. Grieger, K.C. Olson, and G. Stokka. 2002. Effect of increasing proportion of supplemental N from urea in prepartum supplements on range beef cow performance and on forage intake and digestibility by steers fed low-quality forage. J. Anim. Sci. 80:1652-1662.
- Farmer, C.G., R.C. Cochran, and T.A. Wickersham. 2002. Influence of different levels of urea supplementation when beef cows grazing winter pasture are supplemented at different frequencies during the prepartum period. Proc., Western Section ASAS 53:297-300.
- Farmer, C.G. 2002. Effects of various frequencies of supplementation and urea inclusion in protein supplements on low-quality forage use, ruminal metabolism, and performance of beef cattle. Ph. D. Dissertation, Kansas State University, Manhattan.
- Wickersham, T.A. 2002. Effect of infusing protein postruminally with different levels of ruminal protein infusion on the utilization of low-quality grass hay by beef steers. M.S. Thesis, Kansas State University, Manhattan.
- Farmer, C.G., R.C. Cochran, and T.A. Wickersham. 2002. Determining the influence of different levels of urea supplementation when beef cows grazing winter pasture are supplemented at different frequencies during the prepartum period. AES and CES Report of Progress 890, Kansas State University, Manhattan, pp. 162-165.
- Lambert, B.D., E.C. Titgemeyer, G.L. Stokka, B.M. DeBey, and C.A. Loest. 2002. Methionine supply to growing steers affects hepatic activities of methionine synthase and betaine-homocysteine methyltransferase, but not cystathionine synthase. J. Nutr. 132:2004-2009.
- Loest, C.A., E.C. Titgemeyer, G. St-Jean, D.C. Van Metre, and J.S. Smith. 2002. Methionine as a methyl group donor in growing cattle. J. Anim. Sci. 80:2197-2206.
- Loest, C.A., E.C. Titgemeyer, J.S. Drouillard, C.M. Coetzer, R.D. Hunter, D.J. Bindel, and B.D. Lambert. 2002. Supplemental betaine and peroxide-treated feather meal for finishing cattle. J. Anim. Sci. 80:2234-2240.
- Ives, S.E., E.C. Titgemeyer, T.G. Nagaraja, A. del Barrio, D.J. Bindel, and L.C. Hollis. 2002. Effects of virginiamycin and monensin plus tylosin on ruminal protein metabolism in steers fed corn-based finishing diets with or without wet corn gluten feed. J. Anim. Sci. 80:3005-3015.
- Ives, S.E., E.C. Titgemeyer, and T.G. Nagaraja. 2002. Technical note: Effect of removal of microbial cells by centrifugation on peptide and alpha-amino nitrogen concentrations in ruminal fluid. J. Dairy Sci. 85:3059-3061.
- Lambert, B.D., E.C. Titgemeyer, and C.A. Loest. 2002. Effect of glycine supplementation on sulfur amino acid use in growing cattle. Cattlemen?s Day, Report of Progress 890, Agric. Exp. Sta., Kansas State Univ., Manhattan. pp 20-22.
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Progress 01/01/01 to 12/31/01
Outputs
Cattle are being acquired for use in projects that will initiate soon.Mature, pregnant beef cows (135) were selected and randomly assigned to three treatment groups (four pasture replications per treatment) to evaluate the impact of delivering limited quantities of a high-protein supplement during the fall grazing period on body weight and condition change during this period and during the subsequent winter. Birth weight of calves and subsequent calf gain during the spring and summer of 2002 will be monitored. Also, a group of calves is currently being prepared for use in studies to evaluate amino acid utilization by growing cattle. These calves will be ruminally cannulated early next year and used in several experiments to evaluate the impact of ammonia and amino acids on the efficiency of histidine utilization.
Impacts
Projects will evaluate factors that impact the response of cattle to dietary protein. The information generated can be used to improve economic efficiency of cattle production and reduce over-supplementation of protein, which would increase losses of nitrogen into the environment.
Publications
- No publications reported this period
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