Determination of the ruminal escape value and duodenal amino acid flow of rapeseed meal.
A 4 x 4 Latin square metabolism trial was conducted to evaluate protein escape potential, duodenal amino acid (AA) flows, and ruminal digestion effects of rapeseed meal (RSM) when fed with non-endophyte-infected tall fescue (Festuca arundinacea) hay. Four Holstein steers (average BW = 400 +/- 6.5 kg), each equipped with ruminal and duodenal cannulas, were fed twice daily at 0700 and 1900. Protein supplements compared with RSM, soybean meal (SBM), blood meal (BM), and a negative control based on urea (U). Diets were formulated to contain 14% CP. Rapeseed meal-supplemented steers had lower (P < .01) ruminal NDF and OM digestibilities than steers fed SBM. Based on in situ data, the lower NDF, DM, and OM digestibilities that occurred when RSM was fed than when SBM and BM were fed were possibly due to the reduced digestibility of the hulls in the RSM. Ruminal pH was not different (P > .05) among treatments. Blood meal supplementation decreased (P < .01) ruminal and total tract CP digestibilities compared to all other supplements. Ruminal liquid and particulate passage rates were not changed (P > .05) by supplement source. Urea supplementation resulted in the highest (P < .01) ruminal ammonia concentration, whereas BM supplementation resulted in the lowest ruminal ammonia concentration (P < .01). Blood meal resulted in greater (P < .01) dietary protein flow to the duodenum than the other treatments. However, microbial efficiencies, as well as microbial DM and protein flows to the duodenum were not different (P > .05) among treatments.(ABSTRACT TRUNCATED AT 250 WORDS)
Lardy
G P
GP
Department of Animal Sciences, University of Missouri, Columbia 65211.
Catlett
G E
GE
Kerley
M S
MS
Paterson
J A
JA
D000596:Amino Acids / Q000008:administration & dosage / Q000378:metabolism*; D000821:Animal Feed; D000818:Animals; D001937:Brassica; D002417:Cattle / Q000502:physiology*; D004043:Dietary Fiber; D004044:Dietary Proteins / Q000378:metabolism; D004063:Digestion; D005527:Food, Fortified; D005772:Gastrointestinal Transit; D008297:Male; D012417:Rumen / Q000502:physiology*
D000596:Amino Acids; D004043:Dietary Fiber; D004044:Dietary Proteins