Effects of Feeding Protected Tallow on Composition of Milk and Milk Fat

Abstract

Official methods were used to analyze composite samples of milk collected during the 1st 15 wk of lactation from 21 Holstein cows fed a milled ration containing 0 (basal), 15% (medium) or 30% (high) protected-tallow supplement (7 cows/treatment). Protein fractions and amino acid composition of total proteins were determined from samples of individual milking. Melting characteristics of pooled samples were determined by NMR. Milk yield was similar for the 3 treatments, but percent fat and fat yield were higher for cow fed protected tallow. Percentages and yields of protein and solid-not-fat were decreased on the protected tallow treatments, especially for high tallow. Decrease in protein was in the casein fraction. Amino acid composition of total proteins was similar for the 3 treatments. Feeding protected tallow caused decreases in all fatty acids except 4:0, 16:1, 18:0 and 18:1 which increased. NMR indicated that butter from the basal group would be harder than that from cows fed protected tallow.