Table 1.

Cytological features following vaginal smear represent each stage of estrous cycle

Stage of estrous cycle	Nucleated epithelial cells	Squamous epithelial cells	Cornified squamous epithelial cells	Leukocytes
Proestrus	+	-	-	-
Estrus	-	+	-	-
Metestrus	-	-	+	+
Diestrus	-	-	-	+

Proestrus, predominantly consisting of nucleated epithelial cells; estrus, with cornfield squamous epithelial cells; metestrus, consisting of cornified squamous epithelial cells and predominance of leukocytes; and diestrus, consisting predominantly of leucocytes