In  the  present  work,  we  have  investigated the influence of months of the year on the ability of Awassi sheep oocytes  to produce embryos in vitro .Ovaries were collected during months of the year  from local slaughterhouses. All resulting oocytes were subjected to in vitro maturation(IVM), fertilization(IVF) and culture (IVC).  Results showed that month of the year greatly affected the IVM rates (p < 0.0001)  where the highest value was in October and the lowest was in February (80.58 and 30.90% respectively), high significant differences (p < 0.0001) were observed in IVF rates among months of the year, oocytes reached the highest IVF rate in September (41.83%) while IVF rate was the lowest in January  (17.10%) . As for results of  cleavage stages , no significant differences were observed among months of the year, where the values ranged between 30 - 42.18%. The month of the year affected significantly the quality of type1 embryos (p< 0.04) where the rate rose to 71.4 %(October). Under the conception of breeding and non-breeding season , it concluded that months of the year clearly affected IVM and IVF rates of Awassi sheep oocytes .


in vitro embryo production, months of the year, ovine oocytes, embryo quality.

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