Evaluation of ovaries in bitches at different estrous cycle periods by doppler ultrasonography

The aim of this study was to determine the vascularisation in the ovarian tissue with the support of Doppler ultrasonography and to investigate the effectiveness of Doppler ultrasonography in determining the estrous cycle periods in bitches. The animal material of the study consisted of 74 bitches of different breeds between 2-8 years of age and 10-40 kg body weight. Doppler ultrasonography examination was performed to evaluate the vascularisation of the ovaries. Afterwards, vaginal cytology findings and serum progesterone concentrations were evaluated and the bitches were grouped according to the cycle periods. After the examinations, the bitches were subjected to ovariohysterectomy operation under inhalation anaesthesia. The ovaries were examined postoperatively. According to the data obtained from the examinations, they were classified as early proestrous (n= 21), mid proestorus (n= 6), late proestrous (n= 10), estrous (n= 10), early diestrous (n= 10) and diestrous (n= 8). Eight bitches in anestrus period which were diagnosed by the vaginal cytology and one bitch which was suspected to have teratoma after all examinations were excluded from the study. ELISA and FIA methods were used to measure the progesterone concentrations. The lowest concentration of progesterone measured by ELISA method was observed in early proestrous period, while the highest concentration was observed in early diestrous period. The serum progesterone levels in early, mid and late proestrous periods were 1.42 ± 0.12 ng/mL, 1.60 ± 0.23 ng/mL and 2.36 ± 0.12 ng/mL, respectively. However, the progesterone level (4,58 ± 0,15 ng/mL) detected during estrus was statistically higher than those measured in all periods of prooestrus (p < 0,001). Serum progesterone levels in early diestrous (8,29 ± 0,96 ng/mL) and diestrous (7,73 ± 0,71 ng/mL) periods were not statistically different from each other, but they were statistically higher than the other periods (p < 0,001). Similarly, serum progesterone levels determined at ng/mL and nmol/l levels according to FIA method were not statistically different in all periods of proestrus. On the other hand, progesterone levels, which were not statistically different in estrous, early diestorus and diestrous periods, were found to be higher in proestrous periods (p< 0.001). Doppler ultrasonography showed that the findings obtained in the early diestrous phase (1.75 ± 0.31) were scored as low compared to the other periods. Similar to the early diestrous period, it was observed that the scoring in the diestrous period (1,90 ± 0,23) was not statistically different. In the early (2.14 ± 0.17), mid (2.16 ± 0.40) and late (2.40 ± 0.26) periods of proestrous, high scores were obtained compared to the diestrous periods, but the differences between the periods were not statistically significant. In addition, the score obtained during the estrous period (3.60 ± 0.16) was found to be the highest value and statistically different from all other periods (p<0.001). It is thought that the high level of vascularisation observed during the estrous period may provide the detection of the cycle, but it should be taken into consideration that ovulation may already have formed. It is suggested that if a single examination is to be performed in the detection of estrous cycle by Doppler ultrasonography in bitches, the vaginal cytology as well as blood progesterone concentrations should be evaluated collectively. Moreover, the daily Doppler ultrasonography should be performed until the diagnosis is clarified to obtain more accurate results.