Protein value of feather meal for ruminants as affected by blood additions

In situ digestion and growth studies were conducted to determine the effects of adding blood to feather meal. In the in situ and digestion studies, soybean meal (SBM), blood meal (BM), feather meal (Fth) and two combinations of 55% raw blood and 45% feathers (RB + F) were used. Feathers and blood were combined either before or after steam hydrolysis of feathers. Ruminal escape protein of Fth was greater than that of SBM but less than that of BM (P less than .10) determined in situ after 12 h of incubation. Ruminal in situ protein digestion was lower (P less than .10) than for the other treatments (P less than .10) when blood was hydrolyzed with feathers. Total tract digestibility was similar (P greater than .10) for SBM, BM and the mixture of RB + F when the blood was not hydrolyzed. In the growth study, calves were supplemented with urea, SBM, BM, Fth or a combination of BM and Fth (BM + Fth; each supplied an equal portion of supplemental protein). The slope ratio technique was used to evaluate the protein sources. The most efficiently used protein sources were BM and BM + Fth compared to SBM and Fth (P less than .05). There was a numerical but not significant (P greater than .1) complementary effect of adding BM to Fth. Soybean meal and Fth had similar protein efficiencies (P greater than .20). Estimated amino acid flow to the small intestine based on in situ amino acid degradation suggested that the complementary effect observed for BM + Fth was due to BM supplying lysine and Fth providing sulfur amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)