Factors Affecting Ovarian Activity in Donkeys: The Effect of Season, Age and Body Condition Score (BCS)

Abstract

During the period of year (representing spring, summer, autumn, and winter) Jennies at Giza Zoo abattoir were checked for body condition score (from 1 to 5), age (1 to 7 years; 8 to 14 years; and >15 years old). After culling, ovaries of 377 Jennies were collected, two ovaries were weighed, and the number and size of ovarian follicles were recorded. Cumulus-Oocyte Complexes (COCs) were collected after the ovarian follicles have been sliced and scraped, and COCs number and quality were determined. Data indicated that right and left ovaries and overall ovarian weight were significantly increased (P<0.05) in summer than the other seasons. The number of small size ovarian follicles was decreased (P<0.05) in spring than other seasons, while oocytes number and quality were not significantly affected by season. Jennies of 1 to 7 years old showed a significant (P<0.05) smaller left ovary and total ovarian weight than the two other groups. Jennies of 8-14 years old) have a significant high (P<0.05) small size and a whole number of ovarian follicles than the other groups. Jennies with BCS-3 possess a significantly (P<0.05) higher total ovarian weight, total number of ovarian follicles and the total number of COCs recovered than BCS-1 or BCS-4. While the BCS-4 group showed the lowest (P<0.05) number of ovarian follicles and produced less (P<0.05) number of COCs than the other groups. Conclusion: In Egyptian Jennies, ovarian activity was affected by season, BCS and age of the animal, while, COCs yield and quality were more affected by BCS.