Impacts of vitamin C and E injections on ovarian structures and fertility in Holstein cows under heat stress conditions

Abstract

This study evaluated the effect of injecting vitamin C (VC) and E (VE) on size of the preovulatory follicle, volume of the corpusluteum, and pregnancy rates in Holstein cows under heat stress conditions (temperature humidity index > 74). Sixty-two cows wererandomly assigned to one of four treatments: 1, control, n = 15: cows were not supplemented with vitamins; 2, VCG, n = 15: cows weresimultaneously injected i.v. with 500 and s.c. with 2500 mg of VC before and after estrus; 3, VEG, n = 15: cows received an i.m. injectionof 3000 IU of VE before estrus; 4, VCEG, n = 17: cows were injected with VC and VE in the same way and doses as in treatments 2 and3. Treatment did not significantly affect any of the measured variables, despite a numerical increase in pregnancy rates in cows injectedwith vitamins (7.5 ± 7.3%, 9.6 ± 9.4%, 15.1 ± 10.0%, and 18.34 ± 9.9% for control, VCG, VEG, and VCEG, respectively). In conclusion,injections of vitamin C and E did not affect either the development of the preovulatory follicle and the corpus luteum or pregnancy ratesin Holstein dairy cattle under heat stress conditions.