Transvaginal ultrasound-guided oocyte retrieval following FSH stimulation of domestic goats

Abstract

The objectives of this study were to evaluate different ovarian stimulation protocols on donor goats and to develop a safe, repeatable method for harvesting oocytes from FSH-treated does (Experiment I). Based on the preliminary findings of the first experiment, 32 crossbred does were used in a second experiment (Experiment II), 16 that had not been previously aspirated and 16 that had undergone one previous aspiration, were used to fine tune the procedure. Females were randomly subjected to 1 of the 2 ovarian stimulation protocols: Treatment (A) does were implanted with a norgestomet ear implant. Starting 10 d post-implantation, does were administered FSH daily for 4 d. Does in Treatment (B) were treated similarly to those in (A) but were implanted for only 3 d before starting the FSH injections and implants were not removed prior to aspiration. Using a 2 x 2 factorial arrangement, fresh does (n=16), not previously aspirated, were then further randomly assigned to either a laparoscopic aspiration procedure (LAP) or a transvaginal ultrasound-guided aspiration procedure (TUGA). The LAP procedure was performed using a fiber optics. For the TUGA, the doe was placed in dorsal recumbency, and a 5 MHz human transvaginal transducer, attached to the ultrasound unit, was positioned vaginally for oocyte aspiration. In summary, there was no significant difference among treatment groups for parameters evaluated, with the exception of methods for oocyte collection. The number of follicles detected and oocytes harvested using TUGA (9.5 and 4.3, respectively) was less than for females obtained by LAP (17.4 and 14.4, respectfully). The percentage of oocytes recovered from does subjected to the TUGA (68%), however, was similar to those subjected to the LAP (69%). Unlike donor does subjected to a repeated LAP, there was no evidence of adhesions in donor does from the repeated TUGA group. The TUGA approach to oocyte collection should not be overlooked in an effort to decrease the chances of adhesions in valuable donor goats.