Induction and synchronization of estrus in dairy cows using a single injection of PGF2α and GnRH

The aim of this study was to examine the effects of treatment with a single injection of GnRH and PGF2α on estrous response, fertility and service period. A total of 120 lactating Simmental cows were divided into four groups of 30 cows each: group PGF2α 40 was treated on the 40th day post partum with a single injection of 2 mL prostaglandin analogue (Estrumate), group PGF2α 50 was treated in the same way on the 50th day, group GnRH was treated on the 40th day post partum with a single injection of 2 mL GnRH analogue (Receptal), and the fourth group (control) was not hormonally treated. Fertility of cows was not significantly different (p>0.05). The difference in the estrous response and service-period between the control group and experimental groups was statistically significant (p<0.01).