| Abstrakt: |
Feather meal (FM) and hair meal (HM) were found to have 94 and 97.5% crude protein (CP), respectively, of which 84.5% from FM and 67.5% from HM was digestible by pepsin. Data are presented on amino acid composition. Two digestion trials compared a 40% roughage diet (15% CP) containing soybean meal (SBM) with diets in which FM or HM replaced 25, 50 or 75% of the SBM protein. A decrease (P<.05) in CP digestibility was found with increasing levels of FM and HM, but no differences in digestible dry matter or energy were observed among treatments in the first digestion trial. However, dry matter digestibility was decreased (P<.05) at the higher levels of FM and HM substitution in the second digestion trial. In three feedlot studies with finishing cattle which were group-fed, diets contained from 23 to 40% roughage, primarily ryegrass straw. In the first feedlot trial (40% roughage), substitution of FM or FM-urea (40/60, CP basis) for SBM did not affect gain or carcass quality, but feed efficiency was greater for the FM-urea (U) diet. In a second feedlot trial (27.5% roughage), steers fed diets with FM-U or HM-U (50/50, CP basis) were more efficient than those fed dried poultry waste-FM (35/65, CP basis), but there was no effect of diet on carcass quality or daily gain. In the third feedlot trial (23% roughage), daily gain was comparable for animals fed cottonseed meal (CSM)-U, CSM-FM or FM-U (all 50/50, CP basis). Carcass grades were slightly lower (P<.05) in animals fed FM-U, but feed efficiency was slightly greater. Combined data on nutrient composition, protein solubility, digestibility and feedlot performance strongly indicate that FM and HM are satisfactory N sources for ruminants, particularly when fed in combination with U in high roughage finishing diets. |
