Feline vaginal cytology and copulation
Keywords: estrus, feline, copulation, sperm
This image illustrates typical estrous cytology in a cat. It was taken from a Siamese cat within an hour of suspected copulation. The presence of sperm (ringed here) indicate that copulation and ejaculation did indeed occur.
Vaginal cytology is a useful tool in cats for the detection of estrous activity. Although some cats show signs that can be interpreted as those of estrus (vocalizing, rubbing against objects and raising of hind quarters) these may be misleading. In some cases in fact, they are not associated with estrus at all. Also, some cats do not show signs of estrus in the presence of humans and cats are inherently shy breeders, usually copulating in the absence of humans. Finally, cats show no signs of vulva swelling, mucus discharge or post-ovulation metrorrhagia (bleeding from the endometrium).
Vaginal cytology is an essential tool for the diagnosis and management of ovarian remnant syndrome in cats. Cytology will be typical for that of estrus in such cases. As this illustration Also shows, it can be used as a crude tool to examine tom cats for fertility.
Vaginal cytology in cats is a very simple. Vaginal cells are easy to obtain and cytology is easier to interpret than in bitches. Vaginal epithelial cells are either parabasal or superficial with very few intermediate cell types. During estrus, superficial cells predominate. They either have no nuclei or pycnotic nuclei as seen in the image below.
Image size: 1500 x 987 px
During diestrus (as seen below) nucleated cells predominate to the virtual exclusion of superficial cells. The background may contain more debris than during estrus.
During diestrus (as seen below) nucleated cells predominate to the virtual exclusion of superficial cells. The background may contain more debris than during estrus.
Image size: 1500 x 1008 px
Also, in feline vaginal cytology, neutrophils are seldom present in normal cats and the slide background is relatively free of debris.
Also, in feline vaginal cytology, neutrophils are seldom present in normal cats and the slide background is relatively free of debris.
The author is most comfortable using a rayon tipped swab for feline vaginal cytology. Although a Pap brush is superior for vaginal cytology in bitches and is invariable the tool of choice for canids, a domestic cat has a small vulva and the wire center of the Pap brush can catch on its margins. However, either tool can be used. The swab or brush is moistened with saline and spreading the vulva lips with thumb and forefinger, it is introduced into the short and broad caudal section of the vagina. This can be accomplished with minimal restraint in most queens. It is then rolled onto a slide and stained routinely.
