Effect of Dietary Fat and Vitamin E on α-Tocopherol and β-Carotene in Blood of Peripartum Cows

Abstract

Nonlactating cows were fed diets containing 88% grass forage and 12% concentrate (DM basis). Starting 14 d prior to anticipated calving, the concentrate was changed to provide 0 or 200 g of supplemental fat and 0 or 890 IU of supplemental vitamin E daily. Following parturition, cows were fed for 14 d a 50% concentrate diet that provided the same amounts of supplemental fat and vitamin E that were fed during the dry period. Plasma was sampled and analyzed for α-tocopherol and β-carotene. Supplemental dietary fat elevated plasma concentrations of both nutrients during the peripartum period. Supplemental dietary vitamin E elevated concentrations of α-tocopherol during that period. Dietary fat also increased concentrations of plasma cholesterol. When α-tocopherol and β-carotene were expressed per unit of plasma cholesterol, fat supplementation did not affect concentrations. Dietary treatments did not influence concentrations of α-tocopherol in blood neutrophils and did not affect intracellular kill of bacteria by neutrophils. Essentially no β-carotene was found in the neutrophils. For colostrum, dietary vitamin E increased concentrations of α-tocopherol and decreased concentrations of β-carotene. © 1994, American Dairy Science Association. All rights reserved.