Abstract
The changes of plasma total cholesterol (CHO), triglycerides (TG) and free fatty acids (FFA) concentrations were monitored during 8 weeks before and 12 weeks after partrition in 22 Japanese Black Cattle, and their interval days from parturition to the first estrus were compared. The first estrus was observed from day 25 to 53 after parturition. Cows were divided into 3 groups by the interval from partrition to the first estrus (Group 1: within 30 days, Group 2: between 30 to 40 days, Group 3: longer than 41 days). When the changes of plasma CHO, TG, FFA concentrations and body weight during experimental period were compared among the groups, the plasma FFA and relative body weight were not significantly different among the groups, indicating that all cows did not seem to be overfeeded or underfeeded. However, the plasma CHO of group 1 was higher (p<0.05) than that of group 3, on day 5, 28, 42, 49 and 56 after parturition. The plasma TG of group 1 was lower (p<0.05) than that of group 3 on day 14, 42 and 63 after parturition, and also lower (p<0.05) than that of group 2 on day 21, 42, 49, 56 and 63 after parturition. It was found that the day of first estrus after parturition was significantly related to the regression coefficient of the change of plasma CHO in postpartum period (r = –0.766, p<0.01). These results suggest that the change of lipid metabolism during the postpartum period was related to the interval days from parturition to first estrus in Japanese Black Cattle.
