Evaluation of uterine echogenicity at different stages of the sexual cycle in dogs

Determination of the sexual cycle period can be done by vaginal cytology, clinical examinations, anamnesis, and measurement of serum progesterone level. However, there is no study to determine the sexual cycle period in dogs by evaluating the mean gray value (MGL) of the uterus by ultrasonographic examination. The present study aims to investigate whether the sexual cycle period affects uterine MGL values in dogs. For this purpose, 52 dogs brought to Afyon Kocatepe University Animal Hospital Obstetrics and Gynecology Clinic were used. The cycle periods of the dogs were determined by the vaginal cytology method. MGL (mean gray value) measurements of the endometrium were made from the images obtained from ultrasonography examinations. As a result of the measurements, the mean MGL values of the uterus in proestrus, estrus, diestrus, and anoestrus periods were 72,81 (σ:20,95), 61,03 (σ:15,59), 79,39 (σ:20,05), and 75,10 (σ:15,88), respectively. As a result of the statistical evaluation, no significant difference was found between sexual cycle periods in terms of MGL values (P = 0.110). If the proestrus and estrus periods are evaluated as a group (follicular period), and the diestrus and anoestrus periods are evaluated as another group, the mean MGL values were found to be 66,9 (σ: 19,0) for the follicular period and 77,6 (σ: 18,2) for the diestrus-anestrus period. MGL values tend to decrease in the follicular period (P = 0,058). As a result of the findings obtained in the study, it was determined that the evaluation of uterine echogenicity is not a parameter that can be used alone in determining the sexual cycle of dogs but it can give an idea about whether the dogs are in the follicular period and can be used to support the clinical examination.