Although Marston & Chang (1965) have noted that the Mongolian gerbil breeds best by monogamous pairing, mating is always unpredictable even when a pro-oestrous female is caged with a male. This causes great difficulty in obtaining a reasonable number of pregnant animals for experimental purposes. The present study was intended to investigate the feasibility of artificial insemination and induction of pseudopregnancy in the Mongolian gerbil in order to obtain a desired number of pregnant animals.
The female Mongolian gerbils of the Worcester Foundation stock and the Tumblebrook Farm stock (West Brookfield, Massachusetts), 2½ to 7 months old, were maintained in animal quarters at 20 to 24°C, under artificial light from 07.00 to 19.00 hours. They were provided with oatmeal, Charles River rat chow and water, supplemented twice weekly with vegetables or apples.
The females usually came into pro-oestrus 2 to 3 days after an intraperitoneal (i.p.) injection of 5 to