Effect of single dose follicle stimulating hormone on follicular aspiration, in vitro fertilization and pregnancy rate

The present study evaluated Brangus cows treated with single doses of follicle stimulating hormone (FSH) subjected to follicular aspiration after 24 h to assess oocyte recovery, in vitro fertilization and pregnancy rate. Follicles exceeding 3 millimeters in diameter were aspirated, 200 mg of FSH was administered 2 days later, and a new ovum pickup was performed 24 h afterward. These methods were performed 3 times every 3 days. In control, follicular aspirations occurred at intervals of 1-week without FSH administration o. The aspirated oocytes were evaluated, submitted to in vitro fertilization and the embryos were transferred to the recipients. The average recovery of oocytes was higher (p<0.05) in control cows (12.4±1.8) than in treated cows (9.4±1.3). There was no difference (p>0.05) in the mean percentage of viable oocytes (52.0±3.9 and 62.7±4.7%) or the mean percentage of embryos (41.4±4.8 and 41.5±4.2%) among control and treated cows, respectively. The mean percentage of pregnancy did not differ (p>0.05) for control cows (43.8±2.7%), and treated cows (40.9±6.8%). In conclusion, FSH treatment did not improve oocyte recovery, in vitro fertilization, and pregnancy percentage. However, there is possibility of several consecutive ovum pickup every t3 days, concentrating the in vitro fertilization and the pregnancy percentage.