Peripartum performance and metabolism of dairy cows in response to prepartum energy and protein intake.

摘要: Twenty-six multiparous Holstein cows were used to examine the effects of prepartum energy and protein intake on periparturient metabolism lactation performance. Two levels energy, 1.65 Mcal/kg net for (NEL) 1.30 NEL, two protein, 17.0% CP 12.5% CP, tested according a factorial arrangement in randomized block design. Dietary treatments fed ad libitum from 21 d before expected calving date day calving. After calving, all same diet. Increased nutrient density did not affect feed intake, but postpartum was higher high-energy diets. Treatment had no effect cow body weight condition score, however, diets greater balance throughout study. Milk milk component yields unaffected by treatment. Cows lower plasma nonesterified fatty acid concentrations than low (354.3 vs. 439.9 mumol/L). Hepatic triglyceride those low-energy Liver glycogen Acetyl-CoA carboxylase synthase abundance significantly at pretreatment, relative The activity acetyl-CoA lipoprotein lipase greatly decreased with onset lactation. resulted elevated beta-hydroxybutyrate postpartum. Prepartum urea nitrogen increased 3-methylhistidine high treatments. Overall, beneficial lipid improve Increasing content diet appear confer any advantages productivity.