Effects of energy level and protein source on nitrogen kinetics in steers fed wheat straw-based diets.
A 4 x 4 Latin square metabolism trial with a 2 x 2 factorial arrangement of treatments was conducted to determine N kinetics in steers. Steers were fed either untreated (UNT-WS) or alkaline hydrogen peroxide-treated wheat straw (AHP-WS) based diets supplemented with soybean meal (SBM) or blood meal (BM). Single doses of (15NH4)2SO4 were infused into ruminal pools to determine N kinetics. Ruminal NH3N concentrations (main effects) were 3.81, 1.65, 3.18, and 2.28 mg/dL in steers when fed diets that contained UNT-WS, AHP-WS, SBM, and BM, respectively. Ruminal N pool size was greater (P < .05) for UNT-WS than for AHP-WS diets and also was greater (P < .10) for SBM than for BM diets. Nitrogen flux rate into the rumen was not affected (P > .10) by diet. However, production rate of N from the ruminal pool was greater (P < .05) for UNT-WS than for AHP-WS diets and greater (P < .10) for SBM than for BM diets. Nitrogen recycled into the rumen was 33% greater (P < .05) for AHP-WS than for UNT-WS diets and 26% greater (P < .05) for BM than for SBM diets. Nitrogen recycling (percentage of N intake) was 33, 56, 36, and 49% for UNT-WS, AHP-WS, SBM, and BM diets, respectively. The blood urea N (BUN) concentrations were 10.23, 4.58, 7.15, and 7.65 mg/dL for UNT-WS, AHP-WS, SBM, and BM diets, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Sultan
J I
JI
Department of Animal Science, Ohio State University, Wooster 44691.
Firkins
J L
JL
Weiss
W P
WP
Loerch
S C
SC
D000641:Ammonia / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D001769:Blood; D001806:Blood Urea Nitrogen; D002417:Cattle / Q000378:metabolism*; D004043:Dietary Fiber / Q000008:administration & dosage; D004044:Dietary Proteins / Q000378:metabolism*; D002149:Energy Intake; D005527:Food, Fortified; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D012417:Rumen / Q000378:metabolism; D013025:Glycine max; D014908:Triticum
D004043:Dietary Fiber; D004044:Dietary Proteins; D000641:Ammonia; D009584:Nitrogen