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.