Document Type : Research Paper

Author

Member of the faculty of Kermanshah Agricultural and Natural Resources Research and Education Center

Abstract

This experiment was conducted to identify the annual cycle of ovarian activities and to determine the relationship between ovary size and ovarian activity in sheep. For this purpose, at least five pairs of Sanjabi ewes ovaries were collected each week during the one year of study and after weighing of each ovary, the number and diameter of visible follicles at the ovary surface, the weight and volume of the corpus luteum and the number of ovaries containing corpus luteum were recorded. Data were analyzed using general linear model test. The results showed that there was no significant difference between right and left ovaries of ewes in terms of mean weight, relative frequency of large, medium and small size follicles and the relative frequency of the number of ovaries containing the corpus luteum. There was a significant positive correlation between ovary weight of ewes and their ovarian activities. The highest relative frequency of ovulation in right ovaries were observed in December and in left ovaries were observed in June and December (p < 0.05). The lowest relative frequency of ovulation in the right ovarieswere observed in April, June, August and March and in the left ovaries were observed in April, September and March (p < 0.05). Based on the results, the Sanjabi ewes in Kermanshah region have some reproductive activity in spring which indicates the return of a temporary ovarian activity in this season and it can lead to out-of-season pregnancies.

Keywords

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