174 TRANSCERVICAL EMBRYO COLLECTION IN THE DOMESTIC BITCH

Abstract

Embryo collection in the bitch is usually performed via surgical collection or uterine excision. Our objective was to collect embryos nonsurgically, or with minimal surgical invasion. Estrus was monitored using vaginal cytology and progesterone analysis during 1 natural cycle and 13 cycles induced by the submucosal insertion of a 2.1-mg deslorelin implant into the vestibulum of Walker-type hounds (n = 10, 30 kg). Bitches (n = 14 cycles) were transcervically inseminated twice in 12 cycles, (3.3 and 5.2 days post-LH) and once on 2 cycles (Day 6 post-LH) with fresh semen. Uterine flushes (n = 14) using an equine medium (ViGro, Bioniche Animal Health USA Inc., Athens, GA, USA) were done 13 to 15 days after the LH peak. Nonsurgical, nonanesthetized flushes were attempted in 9 cycles. In one cycle an 8-Fr, 55-cm Foley catheter with a 1-mL cuff (SurgiVet, Waukesha, WI, USA) stiffened with a metal stylette was inserted through the cervix using a 22-Fr sheath (63027KL, Karl Storz Veterinary Endoscopy, Goleta, CA, USA) and a 3.5-mm cystoscope, (63325BA, Karl Storz Veterinary Endoscopy) and flushed with 1.5 mL of medium infused and recovered by aspiration. In a one bitch, an 8-Fr polypropylene catheter (Sovereign, Tyco Healthcare, Mansfield, MA, USA) was transcervically passed after failing to pass an 8-Fr Foley catheter, but a flush was not done. In 5 cycles, the 22-Fr sheath could not be passed into the cranial vagina, so a 9.5-Fr, 43-cm cystoscope (27012L, Karl Storz Veterinary Endoscopy) was used to transcervically pass a 5-Fr, non-cuffed catheter (17500/0005, Minitube of America, Verona, WI, USA). Only non-cuffed catheters could be passed through the 9.5-Fr cystoscope, so no flushes were attempted. In 2 cycles, the cervix could not be visualized. Surgical flushes under anesthesia were attempted in 5 cycles. One was by transcervical catheterization using an 8-Fr catheter identical to the nonsurgical attempts, but adding surgical exteriorization of the uterine horns and retrograde flushing with 20 mL of medium. In 4 bitches the uterus was exteriorized by ventral midline laparotomy; one had a pyometra at surgery, and in three, 14-gauge i.v. catheters (Angiocath, BD, Sandy, UT, USA) were placed in the tip and body of each horn, and the uterus was retrograde flushed with 20 mL of medium. No embryos were recovered by the nonsurgical and/or transcervical flushes. Passing the 22-Fr sheathed cystoscope that accommodated a cuffed catheter into the cranial vagina, passing a cuffed catheter, or visualizing the cervix was unsuccessful in 7 of 9 cycles. Uterine distension appeared to cause discomfort during nonsurgical flushes. Three of 5 bitches that had a 5-Fr, non-cuffed catheter were subsequently pregnant. One blastocyst was recovered after surgical flushing with the i.v. catheters in the uterus. Nonsurgical embryo recovery in the bitch was most likely unsuccessful, compared to ours and previous work, due to inabilities to pass a cystoscope into the cranial vagina, to pass a catheter through the cervix, to visualize the cervix, or to create uterine distension using a small volume of medium. Pregnancies were maintained after successful transcervical catheterization of mated bitches.