Abstract

The present study aimed to evaluate hyperovulation using FSH and equine chorionic gonadotropin (ECG) during the breeding season and off-season of Awassi sheep. The experiment was conducted during the breeding season (September 2007) and off-season (January 2008), which was characterized by complete anestrus. Twenty-four Awassi ewes were used, randomly distributed into two groups of 12 ewes each. Estrus was induced in the ewes using vaginal sponges impregnated with progesterone for 12 days. Ewes in the first group received an intramuscular injection of 1200 IU of equine chorionic gonadotropin (ECG) 48 hours before sponge removal. Ewes in the second group received eight decreasing doses of FSH, morning and evening. Ewes were inseminated at the onset of estrus with rams of known fertility. Ovarian response was then calculated by counting the corpora lutea using laparoscopic surgery. Embryos were extracted using a semi-laparoscopic method using a lavage of both uterine horns. The results of the study showed a significant increase (P<0.05) in the number of corpora lutea treated with FSH compared to those treated with equine chorionic gonadotropin (ECG), which were 8.7 ± 0.4 and 4.4 ± 0.5, respectively. An increase in the number of uncleaved follicles (P<0.05) was observed in ewes treated with equine chorionic gonadotropin (ECG) outside the reproductive season. No significant differences were observed in the number of embryos extracted when FSH and ECG were used in the reproductive season, as they were 4.8 ± 0.6 and 4.6 ± 0.6, respectively. However, there was a significant difference (P<0.05) when these two hormones were used outside the reproductive season. An increase in the number of unfertilized eggs was found in hyperovulating ewes when both FSH and equine chorionic gonadotropin (ECG) were used during the breeding season. We conclude from the current study that the use of FSH was superior to equine chorionic gonadotropin (ECG) for inducing hyperovulation in Awassi ewes.