DECREASED PLASMA RETINOL, ALPHA-TOCOPHEROL, AND ZINC CONCENTRATION DURING THE PERIPARTURIENT PERIOD - EFFECT OF MILK FEVER

Retinol (vitamin A), α-tocopherol (vitamin E), and Zn are micronutrients essential for health and performance. We determined the effects of parturition, lactation, and periparturient Ca status on plasma retinol, α-tocopherol, and Zn in 18 Jersey cows during the 2 wk before and after parturition. Six cows developed clinical milk fever. Prepartum plasma concentrations of retinol, α-tocopherol, and Zn decreased progressively in all animals. A nadir was reached at 1 d postpartum when concentrations declined to 38, 47, and 67%, respectively, of prepartal baseline concentrations. Plasma Zn returned to baseline concentrations within 3 d of calving, and plasma α-tocopherol returned toward baseline about 10 d after calving. Plasma retinol remained below baseline concentrations throughout the first 2 wk of lactation. The decline in plasma Zn observed at calving was more severe in cows with milk fever (parturient paresis) than in cows without milk fever. The decrease in plasma retinol and α-tocopherol observed at parturition was similar in cows with or without milk fever. These data document an acute decline in plasma retinol, α-tocopherol, and Zn in the immediate periparturient period and indicate that the decline in plasma Zn is more severe in cows with milk fever. © 1990, American Dairy Science Association. All rights reserved.