Influence of increasing proportion of supplemental nitrogen from urea on intake and fermentation characteristics in beef steers consuming low-quality, tallgrass-prairie forage

Kansas Agricultural Experiment Station Research Reports, Dec 1995

Five ruminally and duodenally fistulated Angus x Hereford steers were used to determine intake and fermentation responses associated with increasing the proportion of supplemental degradable intake protein (DIP) provided by urea. Steers had free access to a dormant, tallgrass-prairie forage. The supplemental DIP was provided by sodium caseinate and (or) urea , at a level that was determined previously to optimize use of a similar forage. Supplemental DIP was balanced with corn starch to provide a final supplement of 40% crude protein. Percentages of DIP from urea were: 0, 25, 50, 75, and 100%. Supplements were given intraruminally. Increasing the percentage of urea as supplemental DIP from urea did not significantly affect forage DM intake; however, fermentation characteristics changed.

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Influence of increasing proportion of supplemental nitrogen from urea on intake and fermentation characteristics in beef steers consuming low-quality, tallgrass-prairie forage

Influence of increasing proportion of supplemental nitrogen from urea on intake and fermentation characteristics in beef steers consuming low-quality, tallgrass-prairie forage H.H. Köster R.C. Cochran E.S. Vanzant K .K . Kreikemeier Part of the Other Animal Sciences Commons Recommended Citation - See next page for additional authors Follow this and additional works at: http://newprairiepress.org/kaesrr This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1995 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. Brand names appearing in this publication are for product identification purposes only. K-State Research and Extension is an equal opportunity provider and employer. Influence of increasing proportion of supplemental nitrogen from urea on intake and fermentation characteristics in beef steers consuming lowquality, tallgrass-prairie forage Abstract Five ruminally and duodenally fistulated Angus x Hereford steers were used to determine intake and fermentation responses associated with increasing the proportion of supplemental degradable intake protein (DIP) provided by urea. Steers had free access to a dormant, tallgrass-prairie forage. The supplemental DIP was provided by sodium caseinate and (or) urea , at a level that was determined previously to optimize use of a similar forage. Supplemental DIP was balanced with corn starch to provide a final supplement of 40% crude protein. Percentages of DIP from urea were: 0, 25, 50, 75, and 100%. Supplements were given intraruminally. Increasing the percentage of urea as supplemental DIP from urea did not significantly affect forage DM intake; however, fermentation characteristics changed. Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 License. Authors H.H. Köster, R.C. Cochran, E.S. Vanzant, K.K. Kreikemeier, G. St Jean, Evan C. Titgemeyer, and Tiruvoor G. Nagaraja This Research Report article is available in Kansas Agricultural Experiment Station Research Reports: http://newprairiepress.org/ kaesrr/vol0/iss1/598 INFLUENCE OF INCREASING PROPORTION OF SUPPLEMENTAL NITROGEN FROM UREA ON INTAKE AND FERMENTATION CHARACTERISTICS IN BEEF STEERS CONSUMING LOW-QUALITY, TALLGRASS-PRAIRIE FORAGE 1 Summary Five ruminally and duodenally fistulated Angu s × Hereford steers were used to determine in take and fermentation responses associated with increasing the proportion of supplementa l degradable intake protein (DIP) provided by urea. Steers had free access to a dormant, tallgrass-prairie forage. The supplementa l DIP was provided by sodium caseinate and (or) urea ,at a level that was determined previousl y to optimize use of a similar forage. Supplementa l DIP was balanced with corn starch to provide a final supplement of 40% crude protein. Percentages of DIP from urea were: 0, 25, 50, 75, and 100%. Supplements were given intraruminally. Increasing the percentage of urea as supplemental DIP from urea did not significantly affect forage DM intake; howev er, fermentation characteristics changed. (Key Words: Beef Cows, Intake, Rumen Fermentation, Forage.) Introduction Previous rese arch has demonstrated limited utilizat ion of low-quality forages when concentrations of ruminal ammonia and other microbial nutrients are low. Providing protein sources with a high concentration of degradable intake protein (DIP) like soybean meal addressed such limitations, but these natural protein sources are expensive. To minimize supplement costs, previous research has evaluated the ef ficacy of non-protein nitrogen (NPN, for example ur ea) for replacing natural proteins as a supplemental DIP source. Generally, response to NPN as a sourc eof supplemental DIP has been poorer than respo nse to natural protein when fed in supplements for livestock on lowquality forages. However, the NPN level in many previous studies was arbitrarily chosen and often represented a high percentage of the total crude protein. It may be possible to includ e low levels of urea in range supplements without significant loss of animal performance. This experiment represents the first in a series designed t o identify optimal level of urea inclusion in "protein" supplements fed to beef cattle eating low-quality, tallgrass-prairie forage. Experimental Procedures Five ruminally and duodenally fistulated Angus × Hereford steers (904 lb) were penned in individual tie stalls with unlimited access to low-quality , tallgrass-prairie forage. Steers were supplemented with an amount of DIP previousl y determined to maximize utilization of a similar forage (.92 g/kg BW). The DIP (380 g/day) was co mprised of sodium caseinate (casein; 90 % CP) and (or) urea (287% CP) and was balanced with corn starch (0% CP) to provid e a final supplement of 40% CP. Percentage s of DIP from urea were: 0, 25, 50, 75, and 100%. The N:S ra ito was maintained at 10:1. The total daily supplement was divided into two equal portions, and administered intraruminall y at 6:3 0 AM and 6:3 0 PM, immediately 1The auth ors express their appreciation to Gary Ritter, Wayne Adolph, Gary Breault, Heath Ritter, and Mike Sheffel for their expert assistance in conducting this experiment. 2KSU Agricultural Research Center - Hays. 3KSU Southwest Research-Extension Center, Garden City. 4Department of Clinical Sciences. before fee ding forage. Supplements were given intraruminall y becaus e they were powdery and infeasible to pellet. Steer swere adapted to diets for 14 days, followed by 4 days of voluntary intake measurement and digesta sampling. Rumina l fluid and DM contents were determine d by manually evacuating the rumen just before (0 hour) and 4 hours after feeding and infusing supplements. Fluid dilution rate, pH, ammoni a N (N H3 N), and volatile fatty acid (VFA ) concentrations were determined on rum inal fluid samples collected at feeding (0 hou r) and 3, 6, 9, 12, and 24 hours after feeding. Results and Discussion Forag e DM intake did not change ( P$.40) with increasing urea levels, indicating that the replacement of natural pr otein with urea, per se, will not restrict nutrient intake from forages. However , because supplements were given intrarum inally, effects on supplement palatability were not evaluated. Other research where high (> 40-50% of the CP eq uivalent) concentrations of urea have been used in grain -based supplements has reported occasional supplement refusal. If supplemen t consumption was compromised, forage intake likely would be reduced. The lack of cha nge in forage intake in our study agrees with the lack of treatme nt effect on ruminal DM and fluid conten ts (P$.20) as well as the lack of response for fluid dilut ion rate ( P$.38). Increasing urea proportions did not affec t(P$.12) pH or total VFA concentration. However, linear increase s (P#.02) in ruminal N H3 N and molar percent acetate were observed with increasing percentag e of urea in supplement . In contrast, all other VFA's decreased ( P#.05) as urea increas ed, except for propionate, which did not chang e (P$.18). In conclusion, although increasin g percentag e of supplemental DIP from urea did not affect forage DM intake, changes occurre d in fermentation characteristics. More informatio n regarding effects of level of urea inclusion on digestion, supplement palatability, and livestock performance is needed. Effect of Increasing Amount of Degradable Intake Protein (DIP) on Intake, Ruminal Contents, Dilution Rate, and Fermentation Characteristics in Beef Steers Fed Dormant Tallgrass-Prairie Forage Acetate Propionate Butyrate Isobutyrate Valerate Isovalerate Acetate:propionate Casein CP:Urea CP (%) Contrasts a 100:0 75:25 50:50 25:75 0:100 64.2 64.4 61.8 61.9 61.2 20.6 21.0 20.8 21.0 21.9 132.0 126.0 132.0 129.0 135.0 5.34 5.31 5.38 4.73 5.62 6.50 6.43 6.42 6.52 6.52 3.32 3.24 3.28 4.29 5.48 80.4 88.5 80.3 79.1 83.8 )))))))mol/100mol ))))))) 73.4 75.0 76.2 75.6 76.5 15.0 15.1 14.8 15.5 15.7 7.03 6.54 6.19 6.54 6.20 1.50 1.16 .99 .84 .61 1.40 1.04 .89 .78 .58 1.66 1.16 .95 .77 .42 4.91 4.96 5.19 4.89 4.93 2.98 .62 4.64 .61 .06 .70 4.17 aProbability of a greater F value. L = li near change with increasing DIP, Q = quadratic change with increasing DIP, C = cubic change with increasing DIP.


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H.H. Köster, R.C. Cochran, E.S. Vanzant, K.K. Kreikemeier, G. St Jean, Evan C. Titgemeyer, Tiruvoor G. Nagaraja. Influence of increasing proportion of supplemental nitrogen from urea on intake and fermentation characteristics in beef steers consuming low-quality, tallgrass-prairie forage, Kansas Agricultural Experiment Station Research Reports, 1995,