Cytologic Characteristics of the Feline Ovary at Different Sexual Stages

BACKGROUND: Cytology is a valuable diagnostic tool in veterinary medicine, allowing rapid and minimally invasive diagnosis. However, its application in the reproductive tracts of small animals is limited, primarily used to assess mammary masses and stage the estrous cycle. OBJECTIVE: This study evaluated the cytologic characteristics of healthy queen ovaries throughout the estrous cycle. ANIMALS: Twenty-four domestic shorthair queens were included and submitted to a conventional ovariohysterectomy. METHODS: A blood sample was obtained to assess the serum concentration of estradiol and progesterone. One ovary was immersed in paraformaldehyde for histology purposes, whereas the other was used for cytology. Blood parameters and histology were used to classify the queens into 4 different groups: anestrous, follicular, luteal phase, and luteal cell phase groups. RESULTS: When comparing the groups, statistically significant (p < 0.05) differences were observed only in the percentage of luteal and mesenchymal cells and mitotic figures. Luteal cells were only present in those ovaries belonging to the luteal phase group. Mesenchymal cells were present in the follicular and the luteal phase groups. Mitotic figures were observed in the anestrus and follicular phases. CONCLUSIONS: It can be concluded that the ovarian cytology in the queen varies according to the reproductive cycle.