Question of the Day

In a bitch that is in estrus and ready to breed look for >90% cornified epithelial cells (angular, sharp edges like corn flakes, tiny pyknotic nuclei or no nuclei) and no inflammatory cells (e.g., neutrophils) on vaginal cytology.

Determine estrus timing with a combination of vaginal cytology, vaginoscopy to evaluate mucosal folds, and hormone assays (e.g., daily serial LH measurement and serial progesterone measurements).

In diestrus vaginal cytology quickly changes, cell type shifts to parabasal epithelial cells, and the number of neutrophils increases. During this phase of the cycle bitches are refractory to breeding.

Click here to see a panel of images showing canine vaginal smears with: cornified cells (estrus), non-cornified cells (diestrus), parabasal cells (anestrus), and intermediate cells (late proestrus).