Effects on beta-carotene, retinol and alpha-tocopherol status of feeding 1st colostrum at 0-2, 6-7, 12-13 and 24-25 h after birth were studied in calves. beta-carotene, retinol and alpha-tocopherol concentrations decreased in colostrum during the first 2.5 d of lactation. Plasma beta-carotene, retinol and alpha-tocopherol concentrations in newborn calves were very low. Plasma beta-carotene concentrations increased up to d 3 after the 1st meal and during the 1st month were higher in calves fed 1st colostrum at < 6-7 h than at > 12-13 h after birth. Plasma retinol concentrations increased up to d 5 after the 1st meal and were higher during the 1st month in calves fed 1st colostrum at < 12-13 h than at > 24-25 h after birth, whereas hepatic concentrations increased up to d 5 independent of time of 1st colostrum feeding. Plasma alpha-tocopherol concentrations increased after the 1st meal except in calves fed 1st colostrum at 24-25 h after birth and were higher during the 1st month in calves fed the 1st colostrum at 6-7 h than at 24-25 h after birth. In conclusion, delaying 1st colostrum intake by more than 12-13 h after birth impaired the plasma beta-carotene, retinol and alpha-tocopherol status during the 1st month of life, but did not negatively influence hepatic retinol concentrations.
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Zanker et al. (2000) studied this question.