Canine Reproduction: Reproductive Organs and Related Structures of the Nonparous, Parous, and Postpartum Bitch

Abstract

SUMMARY Normal morphologic features of the reproductive organs and related structures in 80 female Beagle dogs at various stages of the estrous cycle were determined. Uterine size and weight increased as the bitches matured and entered into proestrus and estrus, attaining maximal size during early metestrus and then decreasing in size as the bitch entered anestrus, but not returning to the size seen in the immature bitch. Characteristic morphologic alteration of the uterus referred to as “corkscrewing” occurred during metestrus. Maximal ovarian weight and structures were found at approximately the time of ovulation, ovarian size decreasing until anestrus and then again increasing in proestrus. Definite cyclic changes were not as clearly evident in adrenal and pituitary glands, although adrenal gland weighed the most during proestrus, and pituitary gland, during early metestrus. Cyclic changes in cellular elements of the reproductive organs were also evident. The greatest cellular changes occurred at proestrus, estrus, metestrus, and after parturition.