title: Effect of a mixture of feather and blood meals on lactational performance of dairy cows.
abstract: An experiment was conducted over 18 wk of lactation to determine the effect of supplemental feather and blood meals (85:15, wt/wt, dry matter basis) fed at two dietary concentrations of crude protein (CP) on dry matter intake and milk protein production. Forty-eight Holstein cows were grouped by parity and assigned randomly at 3 wk postpartum to one of four diets following a 2-wk covariate period. Diets consisted of 50% alfalfa silage and 1) no feather or blood meals, 17.6% CP, and 5.1% ruminally undegradable protein (RUP); 2) 4% mixture of feather and blood meals, 17.6% CP, and 6.3% RUP; 3) no feather or blood meals, 19.6% CP, and 6.3% RUP; and 4) 4% mixture of feather and blood meals, 19.6% CP, and 6.9% RUP. According to the National Research Council, diet 1 was deficient in RUP, diets 2 and 3 were adequate in RUP, and diet 4 contained excessive CP and RUP. Intakes of dry matter and CP were depressed by 11% for cows fed the 19.6% CP diet supplemented with feather and blood meals. For cows fed the 17.6% CP diet, the supplementation of feather and blood meals increased RUP intake, but the supplementation of feather and blood meals to the 19.6% CP diet had no effect on RUP intake. Supplemental feather and blood meals increased the production of milk protein and 3.5% solids-corrected milk by cows fed the 17.6% CP diet. Diets 2, 3, and 4 resulted in similar efficiencies of solids-corrected milk production, but the efficiency of milk protein production specifically was increased by the supplementation of feather and blood meals to the 17.6% CP diet only. Results of this experiment indicate that a mixture of feather and blood meals improves the production of milk protein when supplemented to a diet that meets, but does not greatly exceed, the requirements established by the National Research Council for RUP and that contains alfalfa as the sole forage.
authors.affiliation: Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Grant
authors.forename: S G
authors.initials: SG
authors.lastname: Haddad
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001769:Blood; D002417:Cattle / Q000502:physiology*; D004044:Dietary Proteins / Q000008:administration & dosage; D005241:Feathers; D005260:Female; D007774:Lactation / Q000502:physiology*; D000455:Medicago sativa; D012820:Silage
chemical_list: D004044:Dietary Proteins