title: Aspiration of oocytes from mature and immature preovulatory follicles in the mare.
abstract: Two experiments were conducted to investigate methods for aspirating oocytes from immature preovulatory follicles in the mare. In Experiment 1, the ovary was manipulated per rectum and the follicle was punctured by a needle introduced through the flank. Suction was provided by either a syringe or by a vacuum pump connected to the needle via tubing. The preovulatory follicle was aspirated when it reached a diameter of 32 +/- 2 mm (Group A); 37 +/- 2 mm (Group B); or 42 +/- 2 mm (Group C). There was no significant difference in oocyte recovery rates between the two methods (7/24 vs 3/19). Oocyte recovery rates were higher for Groups B and C (5/14 and 4/12, respectively) than for Group A (1/17; P < 0.05). In Experiment 2, the ovary was held against the internal abdominal wall by the hand inserted into the abdomen via a vaginal incision, and the follicle was flushed after aspiration. Recovery rates were 9/13 (69%) for mares treated with human chorionic gonadotrophin (hCG) and 15/21 (71%) for unstimulated mares. This difference was not significant. The oocyte recovery rate for unstimulated follicles (average diameter 39.7 mm) in Experiment 2 was significantly higher than those for Group B and Group C in Experiment 1 (P < 0.05).
authors.affiliation: Section of Reproductive Studies, New Bolton Center, University of Pennsylvania School of Veterinary Medicine, 382 West Street Road, Kennett Square, PA 19348, USA.
authors.forename: K
authors.initials: K
authors.lastname: Hinrichs
authors.forename: D F
authors.initials: DF
authors.lastname: Kenney
authors.forename: R M
authors.initials: RM
authors.lastname: Kenney