Effect of Seasonal Changes in Photoperiod on Ovarian Morphometry, Ovarian Follicle Diameter, and Oocyte Diameter in Iraqi Local Goats

• Saleh Hussein Saleh1, Ali Shehab Ahmed2

  Author

Through its impact on ovarian function and follicular growth, photoperiodic seasonal variation is one of the most significant environmental elements in controlling goat reproductive activity. The purpose of this study was to examine how ovarian morphometric traits, ovarian follicle diameter, and oocyte diameter were affected by summer and autumn over two photoperiods in local Iraqi goats. Adult female goats (2–3 years old) were ovarically sampled monthly from June to November, and ovarian weight, length, thickness, volume, along with follicle diameter and oocyte diameter were measured using standard morphometric and histological techniques. A Completely Randomized Design (CRD) was used to evaluate the data, and Duncan's Multiple Range Test at P < 0.05 was used to examine the changes across the months. There was a clear seasonal effect for all traits tested, with ovarian weight, length, thickness, volume, and follicle diameter and oocyte diameter being significantly greater in autumn than in summer. The highest values were registered continuously in September and October, while the lowest ones were registered in the summer months. The betterment of these parameters is probably associated with Samane's prolonged photoperiod during autumn, which causes an increase in melatonin, gonadotropin release, follicle development, and steroidogenesis, leading to oocyte quality. In contrast, the short photoperiod in summer, along with heat stress, deleteriously affects ovarian function and its development. In conclusion, seasonal photoperiod is an important factor that influences the ovarian morphology and reproductive performance of Iraqi local goats; autumn provided the most suitable physiological conditions for ovarian changes during summer by increasing follicular maturation and oocyte growth.

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