USE OF A LINEAR ULTRASONIC TRANSDUCER FOR THE TRANSVAGINAL ASPIRATIONAND TRANSFER OF OOCYTES IN THE MARE

A 5 MHz linear ultrasonic transducer was used for the transvaginal asp iration and transfer of oocytes through the use of an ultrasonically-g uided needle. Mares (n=18) with a follicle greater-than-or-equal-to 30 mm were given human chorionic gonadotropin (hCG); follicular aspirati ons were attempted between 17 to 28 hours (mean of 24 hours) later. Oo cytes were recovered from 14 of 18 aspirations (78% collection rate), and intrafollicular oocyte transfers were attempted in 7 recipients. R ecipients were given an injection of hCG approximately 24 hours prior to transfer of an oocyte into the follicle. Two of the 7 oocyte transf ers resulted in twin conceptuses. The techniques used in this prelimin ary study resulted in the recovery of equine follicular oocytes and in the successful intrafollicular transfer of oocytes.