The estrus period of cows is short, usually mating once or twice during the estrus period is sufficient. However, some malnourished cows experience a decline in their reproductive function and slow follicular development, resulting in a delay in ovulation time. Some cows may ovulate earlier and irregularly. For these cows, without rectal examination, the ovulation time cannot be accurately determined. In order to accurately determine the optimal mating period, in addition to conducting trials and external observations, it is also necessary to perform a rectal examination. Check the development of follicles through rectal palpation.

Observation of developmental differences in follicles on both sides of cows using B-ultrasound

The monitoring of young cows using bovine ultrasound showed that the average value of dominant follicles in the left ovary of cows on bovine ultrasound was about 11.85mm, with a total of about 3.18 follicles; The average value of dominant follicles in the right ovary of cows is about 13.09mm, with a total of about 3.09 follicles. The diameter of dominant follicles in the left and right ovaries of cows is not significantly different, and the number of dominant follicles in the left and right ovaries of cows is also not significantly different.

The monitoring of young cows using bovine ultrasound showed that the average diameter of mature follicles in the left ovary of the ovulation follicle wave was about 14.76mm on bovine ultrasound, and the average diameter of mature follicles in the right ovary was about 14.34mm on bovine ultrasound. The diameter of mature follicles on the left and right ovaries of cows is not significantly different. Although there is not much difference between the left and right ovaries of cows measured by ultrasound, the pregnancy rate of the right uterine horn in cows is significantly higher than that of the left uterine horn during pregnancy.