Utilization of liquid acid whey by lactating dairy cows

Abstract

Two trials were conducted, the first of which was a 56 d trial with 24 Holstein cows in mid lactation. Treatments were 100% water (T1) or 100% liquid acid whey (T2). Cows on T2 had decreased DM intake and 3.5% FCM, and increased milk fat and protein. Milk fatty acids shifted towards higher medium chained fatty acids for cows on T2 and higher C18 and C18:1 for cows on T1. Molar % of rumen VFA's for cows on T2 decreased for C2, C3, and branched chain fatty acids and increased for C4, C5, and C6. There was no correlation between storage time of whey and whey intake. In the second trial, treatments were arranged in a repeated 3 x 3 latin square design. Six lactating cows were fitted with duodenal cannulae (2 fitted with ruminal cannulae). Treatments were 100% water (T1), 50% water and 50% whey (T2) and 100% whey (T3). The digesta marker was Cr₂O₃. Periods were 12 d with sampling on the last 4 d. Compared to T1, rumen C2 decreased on T2 and T3 and rumen C5 increased on T3 while milk fatty acids shifted towards higher C12 and C14 and lower C18.