Intraperitoneal Insemination of the Guinea Pig with Synchronized Estrus Induced by Progesterone Implant

Abstract

Female guinea pigs with synchronized ovulation by means of implantation of progesterone-filled tubing (P-tube) followed by a progesterone injection, were inseminated by intraperitoneal injection with sperm suspension. First, to obtain the optimum conditions for insemination, the females were inseminated singly over the range of 1-10 × 107 spermatozoa before and after the synchronized ovulation. The incidence of conception and implantation was 100% in the females given more than 5 × 107/animal at 9:00 h on the 5th day after removal of the P-tube. Second, the reproductive ability of the inseminated females under this optimal condition was observed throughout the pregnancy to delivery. Inseminated females had a mean ± S.D. gestation period of 68.7 ± 0.5 days, a litter size of 2.8 ± 0.6 pups and body weight of 110 ± 14 g. These data were comparable to those of naturally-mated females. Our findings suggest that the artificial insemination by intraperitoneal injection in combination with the synchronized estrus technique is very useful for production control in a small colony of guinea pigs.