ANSC 3323 Lecture Notes - Lecture 5: Follicular Atresia, Controlled Ovarian Hyperstimulation, Follicular Phase
Document Summary
Opu allows us to aspirate follicles smaller than 2 mm and follow follicles larger than 5mm. Opu results in oocytes, not embryos: the oocytes must be fertilized in vitro to get the embryos, can be done every three days because follicular development occurs in waves (cohorts) 4th wave estrus (20-220: most follicles regress after selection. Giving fsh before follicular atresia rescues recruited follicles. Multiple dominant follicles develop and ovulate as a result. Cattle ovulate one day after heat: once oocyte is ovulated it only lasts about 20 hours and then dies. Cattle is not receptive throughout entire process because estradiol and lh are low throughout the cycle except for day 1 and day 21. Dominant follicles suppress growth of subordinate follicles and cause them to become atretic. Superovulation is possible because: the cohort is developed (follicular development in groups/waves) About 7 follicles per wave (that can be followed: improves efficiency, good genetics/oocytes do not go to waste.
