초록
Incidence of retained placenta in dairy cows was investigated in 120 parturitions. Prior to calving, cows were allotted into four groups; 1) control, 2) the infection of Vitamin E (500 IU), 3) the injection of selenium (40 mg), and 4) the infection of Vitamin E (500 IU) and selenium (40 mg). Selenium (Se) and Vitamin E were injected intramusculary 20 d prior to the estimated calving date. No effects of Se or Vitamin E administration alone was observed for number of service per conception, conception rate, and estrus rate (p > 0.05). But the Vitamin E administration with Se significantly (p < 0.05) reduced the incidence of retained placenta and the days required for calving the first service. Incidence of retained placenta was not significantly (p > 0.05) influenced by parity, but it was significantly (p < 0.01) influenced by season, especially, increased during July and August. Concentration of Se in plasma was not significantly (p > 0.05) changed during peripartum period whether the treatment. The results of this study on retained placenta suggest that this disorder will be reduced by the administration of Se and Vitamin E prior to calving in dairy cows.