The occurrence of mating, ovulation and fertilization of ova was established in Large Albino (LA) and Dutch Belted (DB) does following parturition. The effects of increasing intervals to mating, and presence or absence of suckling in the case of the LA does, on the above parameters of fertility were determined.
No depression in successful mating was found in lactating does compared to weaned controls in the early period after parturition. A significant increase in induced ovulation with increased time to mating was established for DB but not for LA does. In the LA animals, suckling significantly depressed the ovulation response to mating.
The percentage of successfully fertilized ova was significantly lower in some of the post-partum mated DB rabbits compared to controls but no treatment effects on fertilization of ova were established for the LA does.
Patterns of ovarian and uterine involution were observed in the LA does. Ovarian involution was characterized both by rapid regression of corpora albicantia and by a decrease in follicular development. This decrease in follicular development suggests a decrease in pituitary gonadotrophin secretion following parturition, and the resultant decline in follicular oestrogens may be responsible for the formation of smaller CL with increased time to mating after parturition.