کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8967177 1101394 2005 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Recruitment and selection of ovarian follicles for determination of ovulation rate in the pig
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم دامی و جانورشناسی
پیش نمایش صفحه اول مقاله
Recruitment and selection of ovarian follicles for determination of ovulation rate in the pig
چکیده انگلیسی
Gonadotropins determine the follicle selection and ovulation rate. Follicle growth is independent of gonadotropins until antrum formation, at which time recruitment occurs. Once recruited, follicles will continue to grow or degenerate. In gilts, visible surface follicles are classified as small (<3 mm), medium (3-6.9 mm) and large (≥7.0 mm). At estrus (day 0), there are ∼15 small and medium follicles, and ∼15 large follicles. By day 3, there may be ∼30 small, 5 medium and no large follicles. During the remainder of the luteal phase, the pool of follicles increases and peaks at day 11-13 with ∼50 small, and 30 medium, but with no large follicles observed. By the start of the follicular phase at day 15, numbers of small and medium follicles rapidly decline, while a pool of medium follicles is selected for the ovulation. The size of large follicles at estrus is heterogeneous (6.5-10.0 mm) but their number is reflective of the subsequent number of corpora lutea found following the ovulation. However, the time of medium follicle selection for ovulation is variable during the late luteal and early follicular phases. Suppression of FSH before and at the time of luteolysis reduces medium and large follicles but does not reduce the ovulation rate. In contrast, suppression of FSH for 3 days or unilateral ovariectomy after 3 days of the follicular phase prevents full ovulatory compensation. Therefore, FSH appears to be involved in the maintenance of a pool of medium follicles that can be selected by LH to mature and ovulate.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Domestic Animal Endocrinology - Volume 29, Issue 2, August 2005, Pages 385-397
نویسندگان
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