Effect of Beta-carotene Supplementation on Plasma Carotene Content and Fertility of Lactating Crossbred Sahiwal Cows

Background: Beta-carotene (BETA) is a precursor of retinol (Vitamin A) and positively influenced on reproductive efficiency in cows. The aim of the study was to determine the effect of orally supplementation of beta-carotene on plasma carotene content and fertility rate of lactating crossbred Sahiwal cows. Methods: Twenty-four disease-free lactating crossbred Sahiwal cows with a close date of calving were randomly divided into two homogeneous groups for Control group (CONT; n = 12) and Beta-carotene group: 500 mg/cow/d (BETA; n = 12) from 7 days post partum (dpp) until 105 dpp thereafter on concentrations of beta-carotene and selected protein and energy parameters in plasma were determined. In addition, effects on fertility rate were studied. Result: Beta-carotene concentrations increased in plasma of beta-carotene (BETA-group) supplemented cows compared to control (CONT-group) cows (p<0.001). In BETA-group cows, urea concentration in blood plasma decreased significantly compared to cows of CONT-group (p<0.001) but did not differ in total protein, albumin, glucose and total cholesterol content in cows of both groups. Occurrence of first post partum estrus decreased ( p<0.001) in beta-carotene (BETA-group: 74 dpp) cows compared to control (CONT-group: 81 dpp) cows. In this study, it was observed that the overall conception rate was higher (p<0.001) in BETA-group: 83.33% (cows pregnant: 10/12) and lesser in the CONT-group: 50.00% (cows pregnant: 6/12). The results of this study indicated that oral supplementation with beta-carotene increased the concentration of beta-carotene and decreased the concentration of urea in plasma and cows with higher blood plasma beta-carotene content improved fertility over cows with lower blood plasma beta-carotene content.