Uso da citologia vaginal na identificação da fase do ciclo estral em cadelas

Abstract

Vaginal cytology is a widely used method in veterinary medicine for evaluating the estrous cycle of female dogs, allowing the identification of cellular changes in the vaginal epithelium in response to hormonal variations. This study aimed to conduct a literature review on the use of vaginal cytology in identifying the phases of the estrous cycle in female dogs and to evaluate its applicability in determining these phases in animals treated at the Clinical School of the Pontifical Catholic University of Goiás. Twenty-one unspayed female dogs treated between January and April 2026 were evaluated, with two excluded from the analysis due to alterations compatible with reproductive disease. Cytological samples were collected using vaginal swabs, prepared on cytological slides, and evaluated microscopically. The analysis allowed the classification of the females into the different phases of the estrous cycle, identifying animals in anestrus, proestrus, proestrus/estrus transition, estrus, diestrus, and estrus/diestrus transition. A predominance of small and large intermediate cells was observed in most of the evaluated phases, in addition to variations in the frequency of superficial cells, neutrophils, red blood cells, mucus, and bacteria according to the stage of the cycle. The most frequent phase was the proestrus/estrus transition, representing 44% of the animals evaluated. It is concluded that vaginal cytology is a practical, accessible, and efficient tool for evaluating the estrous cycle in bitches, assisting in reproductive management, determining the phases of the cycle, and identifying possible alterations in the female reproductive tract.