Protein Nutrition of Dairy Cows During the Transition Period

Abstract

Prepartum DMI, BCS, and BW did not differ significantly. Cows fed AMP postpartum tended (P = 0.10) to produce more 4% fat-corrected milk (FCM) than SB-fed cows (33.8 vs 31.8 kg/d). Gross efficiency (FCM/DMI) was greater (P < 0.05) for the cows fed AMP postpartum than for cows fed SB (1.88 vs 1.70). An interaction of postpartum diet by week (P < 0.05) indicated that cows fed AMP postpartum lost more BW than did cows fed SB. Postpartum concentrations of total protein and beta-hydroxybutyric acid in plasma were elevated for cows fed AMP compared to SB-fed cows (P < 0.05). Hepatic concentrations of total lipid, triglyceride, and glycogen did not differ in either the prepartum or postpartum periods. Feeding higher amounts of MP or feeding AMP in the prepartum period did not improve lactation performance. However, gross efficiency was improved by supplementation of AMP during lactation.