Factors affecting in-vivo fertility of crossbred Egyptian - Italian buffalo semen

Objective: To assess the effect of region, season and year of insemination on in-vivo fertility of Italian-Egyptian crossbred buffalo semen.Methods: A total number of 4 799 female buffaloes were inseminated by frozen semen with at least 50% post-thaw motility of Egyptian-Italian crossbred bulls in three localities in Delta, lower Egypt (El-Behira, El-Sharkia and Damietta) during the period of 2013, 2014 and 2015. The pregnancy rate after two months was evaluated during the four seasons.Results: The rate of pregnancy was significantly (P<0.000 1) differ among the three localities. The effect of year of insemination on pregnancy rate was significantly higher during 2014 and 2015 than 2013 in El-Sharkia and El-Behira. But in Damietta, the rate of pregnancy was significantly higher in 2014 than 2013 and 2015. There were no significant differences among seasons in El-Behira and Damietta governorates but there was significant (P<0.05) differences in pregnancy rate in El-Sharkia. It was higher in summer, spring and autumn than in winter.Conclusions: Localities, year of insemination and season of the year have effects on fertility of crossbred Egyptian-Italian buffalo semen