Evaluation of feather and hair meals as protein supplements for ruminants

Graduation date: 1981The objectives of this study were to nutritionally evaluate various\ud feather and hair meals (FM, HM) as protein supplements for ruminants\ud and to study the in vitro/in vivo relationships of diets supplemented\ud with FM and HM.\ud In vitro (rumen and enzymes) studies, five in vivo digestion\ud trials and a feedlot performance trial were conducted to accomplish\ud these objectives. FM or HM supplied 40 to 50% of the total N in the\ud supplemented diets used for the in vivo studies.\ud In vitro rumen studies showed that HM was a better supplementary\ud N source than FM or cottonseed meal (CSM). Protein supplements were\ud better utilized at lower roughage:concentrate ratios, and urea supplementation\ud improved the utilization of FM. Different degrees of processing\ud had no effect on the level of N in FM. Pepsin-HC1 digestibilities\ud of crude protein (CP) and dry matter (DM) in FM increased with\ud increasing hydrolysis period up to a point and then decreased slightly,\ud but varying the degree of processing (57 to 78% pepsin digestibility)\ud did not affect in vivo digestibility of FM by growing lambs.\ud Utilization of FM was low in in vitro (rumen) but high in in vivo\ud trials, indicating some potential for reticulo-rumen bypass.\ud The final weights, average live and carcass gains, feed consumption\ud and feed efficiency were higher for animals fed FM and HM than\ud for those fed CSM. The FM and HM diets also had superior economic\ud (cost) advantage in converting feed to gain as compared to the CSM\ud diet.\ud In vitro enzyme nutrient digestibility generally increased with\ud increasing enzyme: N ratios. In vivo CP digestion and N retention were\ud best predicted by a pepsin-pancreatin combination. In vitro pepsin\ud DM digestibility was the best predictor of in vivo DM and organic\ud matter (OM) digestibilities, but in vitro rumen digestibility of DM\ud gave the highest correlation with in vivo digestible gross energy (GE).\ud In vitro digestibility of nutrients by pancreatin was a very poor predictor\ud of in vivo digestibility of nutrients in ruminant diets of the\ud type used.\ud This study demonstrated that FM and HM (when properly processed)\ud were superior to CSM (on a per unit of N basis) when fed as the only\ud protein supplement in diets for ruminants. The study also showed\ud that in vitro proteolytic enzyme and rumen digestion studies can be\ud used effectively to predict in vivo digestibilities of nutrients in\ud ruminant diets