Effects of rumen protected methionine on milk yield and milk composition in earlier lactating cow.

摘要

A total of 12 mature healthy Holstein dairy cows, with an average body weight of 580+or-30 kg and milk yield of 22.5+or-2.8 kg, in the early stages of lactation were selected for this experiment. The cows were randomly divided into 2 groups of 6 cows each. Rumen-protected methionine at 20 g was supplemented daily. Results showed that rumen-protected methionine significantly increased milk yield by 10.83% and milk fat by 5.98% in the treated group (P<0.05). Nonsignificant increased in milk protein by 2.15% and decrease in dry matter were also observed (P>0.05).