Plasma antioxidant vitamin status of periparturient cows supplemented with α-tocopherol and β-carotene

Eighteen crossbred cows in their advance pregnancy were distributed into three equal groups. Group I was kept as control, whereas, groups II and III were supplemented with 1000 IU dl-α-tocopheryl acetate (Vitamin E) and 1000 IU dl-α-tocopheryl acetate + 300 mg β-carotene per cow per day, respectively, from 30 days prepartum to 2 weeks postpartum. Blood samples were collected at 30, 20, 10 and 5 days prepartum, at calving and 3, 7 and 12 days postpartum. Vitamin E and β-carotene contents of feeds offered and blood samples were estimated using HPLC. Total Vitamin E and β-carotene intake in the three respective groups was 185, 1185, 1185 IU per day and 397, 397, 697 mg per day. Plasma α-tocopherol concentration at 30 days prepartum was 3.62, 2.74 and 4.10 μg/ml which decreased by 56.6, 17.8 and 33.6% on the day of parturition in the three respective groups. Higher plasma α-tocopherol in groups II and III at calving helped to regain normal plasma Vitamin E status of 3.0 μg/ml for better immune function, within 2 weeks, whereas, unsupplemented cows could not reach this level during this period. Decrease in plasma retinol and β-carotene concentrations was observed in cows of all the groups on the day of parturition which continued to decrease further up to 7 days post-calving in unsupplemented cows (groups I and II), whereas, these levels were maintained in group III cows. Plasma retinol and β-carotene levels were higher in group III cows. Total antioxidant activity of plasma did not differ among groups. The data indicated that the extent of decrease in the levels of α-tocopherol, retinol and β-carotene at parturition can be reduced by supplementing these vitamins during dry period in order to improve their immunity status.