The aim of the study was to investigate the influence of intramuscularly administered human chorionic gonadotropin (HCG) to purebred Arabian mares at 3000 IU dose on induction of ovulation and pregnancy rates.

This study was performed on 73 mares at the ages between 8 and 17. The animals were divided into two groups. The first group (36 mares) received 3000 IU HCG (HCG group) and the second (37 mares) received 2 ml saline (saline group) at the time of natural mating.

In ultrasonographic examination after 48 hours of drug administration, ovulation rates in HCG, saline group were determined as 97.2% and 78.3%, respectively. Ovulation rate in HCG group was significantly higher than in saline (p<0.01).

Pregnancy rates in HCG and saline groups were 75% and 56.75% as detected by sonographic examination after 20 days from mating. There was a significant difference between groups (p<0.05).

As a result, HCG stimulated ovulation significantly. It was concluded that HCG could elevate pregnancy with single mating in cyclic purebred Arabian mares.