159 TECHNIQUES FOR OVUM PICK-UP IN GONADOTROPIN-TREATED ALPACAS

Abstract

The objective of the present study was to evaluate the quantity and quality of oocytes collected when using 2 methods for ovum pick-up and 2 different regimens for ovarian stimulation in live alpaca donors. Thirty-four non-pregnant female alpacas of 3 to 5 years of age maintained at 4100 m elevation in southern Peru were randomly distributed into 4 experimental groups. Groups 1 (n = 8) and 3 (n = 9) received an intravaginal device containing 0.78 mg of progesterone (Cue-Mate^®, Bioniche Animal Health, Belleville, Ontario, Canada) plus an i.m. injection of 1 mg of estradiol benzoate on Day 0; the intravaginal device was removed on Day 7. Groups 2 (n = 7) and 4 (n = 10) received an i.m. injection of 3.1 mg of LH (Lutropin^®, Bioniche Animal Health) on Day 0. Females received 700 IU of eCG (Pregnecol^®, Bioniche Animal Health) i.m. on Day 7 (Groups 1 and 3) or Day 2 (Groups 2 and 4). In all groups, oocyte collection was done 2 days after the injection of eCG. Groups 1 and 2 were subjected to ventral laparotomy aspirating the oocytes from follicles >3 mm in diameter using a 10-mL hypodermic syringe containing 1 mL of aspiration media (Ringer's lactate solution plus 10% bovine serum) and connected to an 18 G × 1 inch aspiration needle. After collection, the follicular fluid was searched and the COC were graded. Groups 3 and 4 were subjected to ovum pick-up by transvaginal recovery using an ultrasound scanner (Parus 240^®, Pie Medical, Maastricht, the Netherlands) equipped with a vaginal probe of 7.5 MHz (MEVA^®, Pie Medical) and a 17G × 55 cm aspiration needle introduced through a needle guide. Follicles >3 mm in diameter were aspirated into 50-mL centrifuge tubes containing 5 mL of aspiration media with 75 IU mL^–1 of heparin. The aspirated fluid was filtered and rinsed using an embryo filter (EmCon^®, Immunosystems, Menomonie, WI), and COC were searched and graded under a microscope based on the intactness of the cumulus cell layers. Data were analyzed by ANOVA. There were no differences (P > 0.05) between groups in the mean number of follicles aspirated per donor (11.0, 13.8, 9.4, and 9.1 for Groups 1 to 4 respectively), and in the mean number of COC recovered per donor (7.6, 7.0, 6.0, and 6.1 respectively for Groups 1 to 4). The proportions of good quality COC were significantly (P < 0.01) different between surgical (81.0 and 79.5% for Groups 1 and 2) and transvaginal/ultrasound-guided (7.4% for Group 3) methods of collection; however, they were similar to the proportion in Group 4 (64.9%) retrievals. The results show that in the absence of an intravaginal device, a similar quantity and quality of alpaca oocytes can be collected when using a surgical approach or minimally invasive ultrasound-guided transvaginal follicular aspiration.