The effect of rumen-protected methionine and choline on plasma metabolites of Holstein dairy cows

作者：Ardalan M^*; Dehghan Banadaky M; Rezayazdi K; Hossein Zadeh N Ghavi

来源：Journal of Agricultural Science, 2011, 149: 639-646.

DOI：10.1017/S0021859610001292

Forty Holstein dairy cows in their first and second lactations were used from 4 weeks prepartum to 10 weeks postpartum to investigate the effects of feeding ruminally protected methionine and choline on plasma metabolites. Cows were randomly assigned to one of the following treatments in a 2 x 2 factorial design 4 weeks before their expected calving dates, using randomized blocks based on parity: no supplement (control), 18 g/d of rumen-protected methionine (RPM) product, 60 g/d of rumen-protected choline (RPC) product, or 18 g/d of RPM + 60 g/d of RPC. Treatments did not affect plasma triglycerides, glucose, total protein, nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), plasma urea nitrogen (PUN) or aspartate aminotransferase (AST) during the prepartum period. For postpartum plasma NEFA concentrations, there were interactions between RPC or RPM and week postpartum. Feeding RPM increased plasma AST concentrations (P < 0.05) and decreased plasma protein concentrations (P < 0.05) in postpartum cows. After calving, feeding RPC increased (P < 0.05) dry matter intake (DMI), milk yield, 40 g/kg fat-corrected milk (FCM) yield and energy-corrected milk (ECM) yield. This suggests that supplemental RPC can improve lactation performance of dairy cows.

• 出版日期2011-10