The effect of administration of gonadotropin releasing hormone analogue at estrus or during luteal phase on reproductive performance of dairy cows maintained under sub-temperate climate

Overall، 531 dairy cows were inseminated with the aim to study their reproductive performance following administration of GnRH analogue on different days of estrous cycle with different doses. These cows were divided into six treatment and one control group. Depending upon different treatment groups، Buserelin acetate was injected at a dose of 10. 5 µg or 21. 0 µg on different days (0، 5 or 12) of estrous cycle in these cows. Control cows were inseminated without any treatment. Buserelin acetate improved conception in cows if administered either on day 0 along with AI or on Day 5 or 12 post insemination. The highest CR was recorded when 10. 5 µgGnRH analogue was administered on day 12 post AI. The doses of 10. 5 µg or 21. 0 µgwere equally effective when instituted on day 12 post AI.