Effect of Supplementing Periparturient Cows with Vitamin E on Distribution of α-Tocopherol in Blood

Abstract

Holstein cows were fed 0 or 1000 IU/d of supplemental vitamin E during the dry period and injected with placebo or 3000 IU of vitamin E at 10 and 5 d prior to anticipated calving. Blood was collected at various times, starting at 60 d prepartum (dry off) and concluding 30 d postpartum, and separated into plasma, red blood cells, and neutrophils. Oral supplementation increased concentrations of α-tocopherol in plasma and red blood cells on 10 d, but not on 5 d prepartum. Injection of vitamin E increased α-tocopherol in plasma, red blood cells, and neutrophils at d 5 prior to and on the day of parturition. Concentrations of α-tocopherol and cholesterol in plasma were correlated, and both were at their nadir at parturition. Concentrations of α-tocopherol in plasma and red blood cells were correlated, but the correlation increased when plasma α-tocopherol was expressed per unit of cholesterol. α-Tocopherol in plasma and neutrophils had a low correlation. Injection of α-tocopherol increased its concentration in plasma, red blood cells, and neutrophils during the periparturient period. Concentration of α-tocopherol in plasma of periparturient cows may be limited by its low lipid content, and transport mechanisms for α-tocopherol may differ between red blood cells and neutrophils.