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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #123400
Title: EFFECTS OF UREA, ISOLATED SOYBEAN PROTEIN AND BLOOD MEAL ON GROWING STEERS FED A CORN-BASED DIET

Author
item KNAUS, W - UNIV AGRI SCIENCE AUSTRIA
item BEERMANN, D - UNIVERSITY OF NEBRASKA
item TEDESCHI, L - CORNELL UNIVERSITY
item CZAJKOWSKI, M - CORNELL UNIVERSITY
item FOX, D - CORNELL UNIVERSITY
item Russell, James

Submitted to: Animal Feed Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2002
Publication Date: 10/1/2002
Citation: KNAUS, W.F., BEERMANN, D.H., TEDESCHI, L.O., CZAJKOWSKI, M., FOX, D.G., RUSSELL, J.B. EFFECTS OF UREA, ISOLATED SOYBEAN PROTEIN AND BLOOD MEAL ON GROWING STEERS FED A CORN-BASED DIET. ANIMAL FEED SCIENCE AND TECHNOLOGY. 2002.

Interpretive Summary: The Cornell Net Carbohydrate Protein System (CNCPS) is a computer model that predicts the milk production and weight gain of cattle from dietary ingredients. The CNCPS has been validated with a variety of animal studies, but the effect on amino acid nitrogen on microbial growth in the rumen had not been confirmed. Feeding trials were conducted with various nitrogen sources, and animal performances were compared to predictions derived from the CNCPS. These comparisons indicated that CNCPS has sufficient accuracy to allow appropriate nitrogen supplementation of the diet. The CNCPS has allowed farmers to design more efficient rations for dairy cattle.

Technical Abstract: The Cornell Net Carbohydrate and Protein System (CNCPS) model 4.0 was used to create 4 dietary treatments: 1) A 30% ruminal N deficient control diet, 2) a urea supplemented diet balanced to meet ruminal N requirements, but deficient in predicted peptide balance, 3) a urea/isolated soy protein (ISP) supplemented diet predicted to meet ruminal N and peptide balance requirements, and 4) a urea/ISP/blood meal (BM) supplemented diet predicte to meet ruminal N and peptide balance, and to exceed total metabolizable protein (MP) requirements. The steers were fed at 95% ad libitum, offered in equal amounts at hourly intervals, and were injected with 500 mg of estradiol-17b twice daily. Nitrogen intakes of 82, 133, 134, and 161 g/d, resulted in N retention rates of 20, 38, 42, and 58 g/d (P<0.001) when the control, urea, urea/ISP, and the urea/ISP/BM diets were fed, respectively. Digestibilities of DM and OM were enhanced & % on average (P<0.04) with all lsupplemented diets, with corresponding improvement in N digestibility of 20% (P<0.001). Adding soluble isolated soy protein (urea/ISP diet) did not improve digestibility of any diet component or improve N balance, but it reduced daily urinary N by 6 g when compared with the urea-supplemented diet. N retained was increased from 24 to 36% (P<0.03) when the combination of all three N sources was fed, as compared with the control diet. Urea, soluble isolated soy protein, and BM supplementation all contributed to improved efficiency of N retention. Results demonstrate that N balance responses validate use of the CNCPS for predicting and balancing ruminal N requirements. Supplementing a corn-based diet with a combination of urea, rumen soluble true protein and BM to balance the rumen for N & peptides, & iciency of protein gain.