Abstract
Twelve obese dairy cows were administrated with 50, 000 IU of vitamin A every day from 8 weeks prepartum to 13 weeks postpartum. One week before parturition, body weight was 805.2 kg on the average, showing a tendency to be obese. Plasma glucose level increased at the parturition, decreased thereafter and showed a minimum 4 days postpartum. The level of nonesterified fatty acids and ketone bodies increased from partrition. A high level continued until 2 weeks after calving. Plasma cholesterol, phospholipid and vitamin A concentrations began to decreased 3 weeks prepartum and remained at a low level until 3 weeks postpartum. Vitamin A level in the milk showed 424.4 IU/dl on the average at parturition and then decreased rapidly until one week after calving.
It was concluded that cows showing a tendency to be obese before parturition were apt to suffer from an insufficient ingestion of energy after parturition. Then, a low level of vitamin A in plasma in these cows after parturition was considered to be affected with metabolism of retinol-binding protein in the livers as a result of fatty liver caused by mobilization of body fat reserve.
