Changes in the histomorphology of the canine cervix, ovary and steroid hormone levels through the oestrous cycle

The importance of canine reproduction is steadily increasing and little is known about the canine cervix and ovary so far. The aim of this study is to describe the histomorphology of the canine cervix, ovary and to determine its correlation with the stage of oestrous cycle and to circulating concentrations of progesterone (P4) and estradiol17beta (E2) and vaginal cytology respectively. Twenty healthy and sexually mature bitches with ages ranging from 2 to 8 years were assigned to the experiment. Ovariohysterectomies were performed according to standard procedures through median laparotomy access. Ovaries and cervix uteri were collected from 20 cross bred bitches at the time of routine ovariohysterectomy. Canine estrous cycles were determined by clinical, macroscopical and histological findings. Histomorphological examinations were performed to evaluate epithelial thickness and epithelial layers of cervix uteri and ovary tissue were significantly influenced by the stage of cycle.The aim of this study is to investigate the histomorphological structure of the cervix and ovary in the cycle phase of non-pregnant bitches. This study showed that the cervix and ovary undergoes cyclic changes during the canine oestrous cycle, in particular in association with circulating P4 and E2 concentration.