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Effects of Somatotropin on Ovarian Activity in Native Breed Ewes Pretreated With Progesterone
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Abstract: ABSTRACT:
The present study was conducted to investigate the effects of somatotropin administration on ovarian activity in a period of breeding season characterized by anestrus or low incidence of cyclicity. This study was carried out on 11 sexually mature ewes of 2-3 years old which were randomly allotted into control (5 ewes) and somatotropin-treatcd ewes (6 ewes) The results revealed that somatotropin increased the number of medium sized antral follicles on the day of estrus, ovulation rate and the proportion of double ovulator ewes and decreased the number of small sized antral follicles on the day of estrus on comparison with those of control. Regarding corpus luteum characteristics, the difference between the two groups in the total volume of corpus luteum was numerical rather than statistical; however, the functional capacity of corpus luteum (blood level of progesterone) of somatotropin-treated ewes out-performed that of control ones. Moreover, in each group, there were significant correlation and regression coefficients between progesterone level and total volume of corpus luteum; furthermore, the regression coefficient of somatotropin-treated ewes was higher. Regarding steroid hormones, somatotropin significantly reduced estradiol-17B level on the day preceding estrus; conversely, progesterone level was higher during the luteal phase of the treated ewes. In a nutshell, the luteal phase of control ewes was short while that of treated ewes was of normal length as indicated by progesterone level. Moreover, the proportion of double ovulator ewes and those having functional corpus luteum in the treated ewes were higher.
Key words: Anestrus, Antral Follicles, Corpus Luteum, Native Breed Ewes, Ovulation Rate, Sex Steroids.
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| Publication year |
2004
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| Pages |
61-76
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| Availability location |
معهد بحوث التناسليات الحيوانية
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| Availability number |
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| Organization Name |
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| Author(s) from ARC |
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| External authors (outside ARC) |
امل محمود ابو المعاطى
المركز القومى للبحوث
فتحى الفار
كلية الطب البيطرى-جامعة القاهرة
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| Agris Categories |
Animal physiology - Reproduction
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| Proposed Agrovoc |
Anestrus, Antral Follicles;
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| Publication Type |
Researsh & Applied Activities
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