Effect of Beta-Carotene Supplementation on Reproductive Performance of Lactating Holstein Cows

Abstract

Fifty-four lactating Holstein cows were assigned by parity and calving date to a 2 × 3 factorial arrangement of a randomized block design to determine effects of β-carotene supplementation and ration fiber content on reproduction. Because ration fiber treatments did not differ in their effects on reproductive performance, data for β-carotene analyses were pooled over the three rations. From 3 to 98 d postpartum, cows were individually fed either 0 or 300 mg supplemental β-carotene daily by adding it on top of their complete mixed ration. By wk 3 postpartum, concentrations of β-carotene in blood serum were higher in cows fed supplemental β-carotene and remained higher throughout the experimental period. Feeding supplemental β-carotene had no effect on the interval from the time of parturition to uterine involution, ovulation, first observed estrus, or conception. Feeding β-carotene did not influence incidence of cystic follicles based on palpation, ovarian cyclicity based on blood progesterone patterns, peak progesterone concentrations, or first service conception rate. Cows fed supplemental β-carotene required fewer treatments for clinical mastitis. Reproductive performance in lactating Holstein cows was not improved by feeding supplemental β-carotene. © 1988, American Dairy Science Association. All rights reserved.