11:067:327 Lecture Notes - Lecture 11: Gestation, Breastfeeding, Luteal Phase
25 Apr 2016
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Document Summary
Heat ensures mating around the time of ovulation. Provides female repeated opportunity to copulate/become pregnant. Sexual receptivity/copulation 1st half of cycle, before ovulation. If no conception another estrous cycle begins. If conception anestrous period begins and estrous cycles cease. Estrous length of the estrous cycle . Pregnancy possible year round some seasonal differences in fertility. Short in most species (~20% of total) = 80% of entire cycle in most animals. Begins when p4 decrease (luteolysis) and e2 increase at estrus. Cl formation and start of p4 secretion. Ruptured follicle differentiates or luteinizes to form cl. Cl is fully functional and p4 is high. If no copulation postestrus period follows no ovulation, no cl forms. No metestrus, no diestrus, no luteal phase. If mating occurs ovulation induced cl forms, increased p4. Proestrus (9 days), vaginal swelling and blood tinged discharge, Estrus (9 days), receptivity, lh/fsh peak, e2 decreases, 1o oocyte ovulated, 48 hour fertilisation delay. Due to low gnrh low fsh/lh.
