Characterizing the estrous and ovarian activity of Saidi sheep throughout the year
Abstract: Thirty Saidi ewes were used to study the effect of season on estrous and ovarian activity most of the ewes showed estrous in autumn(95.5%) followed by summer (83.3) and winter (80%). Meanwhile only . 53.3% of the ewes exhibited estrus in spring season in respect to month of the year the highest estrous activity was observed during the period from October to January and in July the sexual activity mainly reduced during the period from February to June being the lowest in April (30%). In spring season 53.8% of the ewes showed long estrous cycle (> 19 day). While 48.8 54.6 and 64.9% showed normal estrous cycle length (17-19 days) ,during summer . autumn and winter. respectively. Moreover. normal estrus durations (30- 36 hrs) were recorded in 63.2 46 and 58.3% of the ewes during summer. autumn and winter. Respectively laparoseopie examination showed that all Saidi ewes were ovulated in autumn (100%) while 73.7. 78.1 and 62.5% were ovulated in spring summer and winter . respectively. Some of the ewes showed a great number of ovulation without estrus sign (silent ovulation). especially in spring season Plasma progesterone concentrations during the luteal phase prove the existence of some ovulation unaccompanied with estrus, where cycles ending with ovulatory anestrous were characterized with much lower progesterone levels during the luteal phase compared to cycles ending with ovulatory estrus. A marked seasonal change in ovulation rates was observed. Where the ovulation rates were higher in summer . autumn and winter (2.03 ,0.2 1.9±0.5 and 1.9±0.4 respectively) than that in spring season (1.5 ,0.2 ) the highest ovulation rate and numbers of large follicles recorded in summer season, confirm the fact that the ovulatory follicles are larger than the non- ovulatory ones. Saidi ewes considered as sheep with nearly no reproductive seasonality with estrous cycles distributed along the year although there was a reduction in the estrous and ovarian activity during spring.
Key words: Sheep, Season, Estrous Cycle, Ovulation, Ovarian follicles .
Publication year 2008
Pages 325-339
Availability location معهد بحوث الانتاج الحيوانى-شارع نادى الصيد- الدقى- الجيزة
Availability number
Organization Name
serial title Egyptian Journal of Basic and Applied Physiology
Author(s) from ARC
Agris Categories Animal physiology - Reproduction
AGROVOC
TERMS		 Ewes. Ovarian follicles. Ovulation. Seasons. Sheep.
Proposed Agrovoc Estrous Cycle;
Publication Type Journal
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