USE OF ANTIOXIDANTS TO IMPROVE THE PREGNANCY RATE IN BEEF CATTLE SUBMITTED TO A SYNCHRONIZATION PROTOCOL WITH PROGESTERONE (P4)

Abstract

Estrus synchronization with progesterone is commonly used in farms with better reproductive control. Free radicals production, i.e. oxidative stress, is associated with progesterone levels. The oxidative stress is responsible for aggression to the cellular membrane, leading to a lise and lipoperoxide formation. In this work, the antioxidant compensatory effect (Vitamins C and E) associated with the exogenous progesterone implant (P4), used in estrus synchronization protocols in cattle, was evaluated. Twenty-five cows were randomly selected in 5 different groups: 1) control without P4, 2) control with P4, 3) P4 + vitamin C and E, 4) P4 + vitamin E, 5) P4 + vitamin C. The lipid lipoperoxidation was measured trough Thiobarbituric acid reactive substances (TBA-RS) and Glutatione Peroxidase enzyme (GSHpx) at days 0 and 7 of the estrus synchronization protocol. The use of vitamin E, in this experiment, showed a better pregnancy rate, however, the results must be validated before orienting the use of the vitamin in cows synchronized with P4.  

KEYWORDS: Antioxidants, cows, oxidative stress, pregnancy rate, progesterone.