Reproduction Abstracts

The present study aimed to compare between the effect of hCG and GnRH analogue treatment post laparoscopic insemination on reproductive performance of ewes. Oestrus synchronization was performed for 120 ewes (Najdi=60 and Naeimi=60) using intra-vaginal progesterone sponge and equine chorionic gonadotrophin (eCG). Semen was collected from six proven fertile rams by artificial vagina. Ewes were laparoscopic inseminated 48–50 h after sponge withdrawal,and divided randomly into three groups. Group A: ewes were not given any treatment (control). Group B and C: ewes were injected with 500 IU hCG or GnRH (8 μg buserelin), respectively. Reproductive performance traits including pregnancy rate, fecundity, prolificacy, type of birth, litter weight, lamb’s birth weight, gender ratio, lamb mortality rate and gestation length were calculated. The results revealed that the pregnancy rate, fecundity, prolificacy, triplet percentage, litter weight and lamb’s birth weight were significantly (P<0.05) higher in hCG treated ewes (65.7, 64.9, 134.8, 204.2, 22.0, 7.26, 3.65, respectively) in comparison with other groups, whereas GnRHewes had higher male percentage and longer gestation length (P<0.05) than the other groups. Najdi and Naeimi ewes did not differ (P>0.05) in all evaluated reproductive performance traits except for gestation length and birth weight; Najdi ewes had longer (P<0.05) gestation length and lighter (P<0.05) birth weight than Naeimi ewes. In conclusion, hCG treatment post insemination improved most of reproductive performances of Najdi and Naeimi ewes, while GnRH treatment increased male percentage and gestation length.