Comparison of follicle diameter and uterine edema in Thoroughbred and Dutch mares during breeding
Subject Areas : clinical veterinary science
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Keywords: mare, Thoroughbred, Dutch, follicle diameter, uterine edema during estrus.,
Abstract :
Determining the exact time of ovulation is essential to increase the success of insemination or breeding. An increase in the diameter of the follicle, serration inside the follicle, thickening of the granulosa layer, a change in the shape of the follicle from spherical to oval and its tip in the ovulation pit, the observation of echogenic grains inside the non-echoic fluid, and loosening of the follicle and a decrease in uterine edema are signs of approaching ovulation. In this study, 71 Thoroughbred mares and 38 KWPN Dutch mares, aged between 8 to 22 years, were examined from April to August 2024. A 5 MHz transrectal ultrasound was used to determine the timing of ovulation, measure the diameter of pre-ovulatory follicles, and assess the severity of uterine edema within 48 hours. All the mares studied were pregnant after studying breeding. The findings revealed that the median degree of edema in the Thoroughbred breed was 2, while in the Dutch breed, it was 1.75 (p < 0.001). The median follicle diameter in Thoroughbreds was 47 mm, while in Dutch mares it was 48 mm, with the Mann-Whitney test indicating a significant difference (p < 0.001). The median diameter of ovulatory follicles in the left ovary was 46 mm and in the right ovary was 48 mm (p < 0.001). The ovulation rate for Thoroughbred mares in the right ovary was 30 cases (42%) and in the left ovary was 41 cases (58%) out of 71 cases. In contrast, the ovulation rate for Dutch mares in the right ovary was 20 cases (53%) and in the left ovary was 18 cases (47%) out of 48 cases (p = 0.095).
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