Effects of Dietary Energy Intake During a Perinatal Period on the Fatty Liver, Blood Composition and Milk Protein in Cows

Abstract

Two experiments were conducted to investigate the effect of dietary energy intake before and after parturition on fatty infiltration in the liver, blood composition and milk protein in cows. In the dry period, ten cows received a diet with 130% of normal energy requirement (experiment 1), while eight cows received a diet with 80% of required energy (experiment 2). At 16 weeks postpartum, the cows were divided into two groups by their level of energy intake, that is 80% and 100% in experiments 1 and 2, respectively. In the experiment 1, cows with an 80% postpartum feeding had average 18% of fatty infiltration in liver cells at 2-week postpartum, while high-yielding cows had more than 40% fat in the liver for a month. However, fatty infiltration was hardly observed in cows fed at the 100% feeding level. In the experiment 2, the ratio of fatty infiltration averaged 12% for cows at 80% feeding level, and 10% for cows at 100%. Cows with more than 20% of fatty infiltration retained over 14% of the pigments after 30 min by the bromusulphalein test, thus showing a depressed liver function. These indicate that extensive mobilization of fatty acid during early lactation may be the prime cause for fatty liver, while overfeeding during the dry period may not result in fatty liver under appropriate feeding conditions after parturition.