Transcervical Transfer of Porcine Embryos under Practical Conditions.

Abstract

The aim of this study was to develop the transcervical method of pig embryo transfer using a rubber spiral catheter. A total of 587 ova and embryos were surgically collected on Days 4 to 6 (Day 0=onset of oestrus) from 36 donors, of which 456 transferable embryos were transcervically transferred to 25 synchronous (0 or ± 1 day) recipients, without any premedical treatment, using a sterile rubber spiral catheter covered with a vinyl sheath. Embryos (the mean number ± s.d.=17.8 ± 7.9) were transferred to each recipient through the catheter with either 30 ml or 50 ml of phosphate buffered saline, which was supplemented with 0.4 mg/ml amikacin sulfate and 10% fetal calf serum, by the 2- or 3-stepwise method. Out of 25 recipients, 16 recipients became pregnant (64%) and farrowed (64%). The mean number of piglets farrowed (± s.d.) was 3.1 ± 1.6, and the mean embryo survival rate (± s.d.) was 16.7 ± 7.6%. No backflow was detected during and immediately after embryo transfer in any cases. The pregnancy and farrowing rates were 44% (4/9), 60% (6/10) and 100% (6/6) as they related to the combination of resistances to rotation of the catheter and to infusion of PBS with a syringe, (+, +), (+, -) and (-, -) in order, respectively. The insertion depth of the catheter in the case of (-, -) was significantly larger (P<0.01) than that in the cases of (+, +) and (+, -). No differences in the number of piglets farrowed and in the embryo survival rate were observed between the three combinations with respect to the resistance. The results indicated that a high pregnancy rate can be achieved by the transcervical transfer of pig embryos using a rubber spiral catheter when no resistances both in the rotation of catheter and infusion of fluid containing embryos are detected during embryo transfer.