Relationship between triacylglycerol concentration in the liver and first ovulation in postpartum dairy cows.

摘要

To study the relationship between hepatic lipidosis (accumulation of triacylglycerols in the liver) and the first postpartum ovulation, 32 non-pregnant, non-lactating dairy cows were fed a high-energy diet to induce overconditioning, or were fed a recommended diet (controls). After calving, compared with controls, treated cows entered a deeper negative energy balance state (-37.3 vs. -58.2 MJ per day; P<0.01), required more days to reach the nadir of negative energy balance (1.5 vs. 3.7; P<0.05), required more days to regain positive energy balance (20.4 vs. 58.8) and lost more body weight (-12.0 vs. -51.6 kg; P<0.001). Treated cows accumulated more triacylglycerols in the liver (P<0.05) and had higher plasma concentrations of non-esterified fattyacids and 3-hydroxybutyrate after calving than control cows. The number of days to first ovulation tended to be higher for treated than for control cows (51.9 vs. 35.7). Pooled data of both groups showed that the liver triacylglycerol concentration waspositively correlated (P<0.05) with the number of days to first ovulation. It is concluded that the negative energy balance caused increased mobilization of body fat and resulted in greater amounts of triacylglycerols in the liver of treated cows.