The ovary is the receptor of exogenous hormones during embryo transfer. Its texture, elasticity and degree of development are important factors that affect the exogenous hormones to stimulate ovulation of follicles, fertilization and development into embryos. Foley et al. studied the weight of the corpus luteum of four dairy cattle breeds by veterinary B-ultrasound and found that the weight of the corpus luteum increased from 1.05±0.47 g to 5.03±1.56 g from the 2nd to the 5th day to the 12th day of the estrus cycle, and the weight gain was the fastest before the 8th day, and it began to degenerate on the 18th day. Xu Zhongjun et al. studied the morphology of the corpus luteum at different periods by veterinary B-ultrasound and found that the corpus luteum at 3 days after ovulation was not very prominent and was a soft hemispherical object. The corpus luteum at 9 to 16 days accounted for 1/2 or 3/4 of the entire ovary and was relatively full. The protruding part of the unpregnant cow gradually disappeared 16 days after ovulation, and the volume was reduced, and the protruding hemispherical shape was shrunk and flattened. Veterinary B-ultrasound shows that the formation of the corpus luteum is a direct proof of ovarian ovulation and also determines the number of embryos formed. Table 4 shows that the number of embryos is positively linearly correlated with the size of the ovary and the number of corpora lutea. The embryo availability rate is the highest at 76.3 when the ovarian size is 63±3.2 mm to 52±2.3 mm on the day of embryo transfer, while the number of corpora lutea and embryo transfer are the highest at 72±3.4 and 58±4.1 mm, which are 14.5±3.2 and 10.4±2.5 respectively. Some people have predicted the effect of superovulation based on the direct examination of the corpora lutea on the ovaries before superovulation. The results showed that the corpora lutea on the ovaries are prominent and elastic, and can occupy about half of the ovaries, and the number of embryo transfer and available embryos are high. Therefore, studying the ovaries and corpora lutea to predict the number of embryos is an important way for people to explore improving animal reproductive performance through embryo transplantation. It is feasible to use veterinary B-ultrasound detection technology to examine the development of ovaries and follicle corpora lutea during synchronous estrus and superovulation in dairy cows, and to predict the effect of superovulation.

Veterinary B-ultrasound observation of the effect of ovarian cysts on the number of embryos

Ovarian cysts are common infertility in veterinary clinics. It is generally believed that the animal's endocrine disorder, excessive estrogen secretion, and decreased luteinizing hormone (LH) in the blood cause the follicles to grow too large and fail to ovulate. In this experiment, on the day of embryo flushing, it was found that one of the four cases of ovarian cysts flushed out one blastocyst, one flushed out three morulae, and the other two cases did not flush out embryos. In addition, in practice, I have also encountered two cases of cows with follicular cysts who became pregnant without any hormone treatment. Through veterinary B-ultrasound observation, the reason may be that the follicles on the ovaries are dominant follicles, and the corpus luteum is formed during the superovulation process. It is also a new corpus luteum before the 5th day of the sexual cycle, and prostaglandins have no dissolving effect on it, so cloprostenol has no effect on it. The progesterone secreted by the corpus luteum resists estrogen.