The appearance of ovarian cysts in sows can be observed through animal B-ultrasound machines. Ovarian cysts are the most common in ovarian diseases and can occur on one or both ovaries. This disease can be divided into two types: follicular cysts and corpus luteum cysts, of which follicular cysts account for about 90%. The diameter of vesicles observed by animal B-ultrasound can reach over 5cm, and some can weigh over 500g.

The growth, development, and ovulation of follicles rely on the balance of FSH and LH secreted by the pituitary gland, especially FSH, which is crucial for ovulation. If the two are imbalanced and LH secretion is insufficient, ovulation will not occur, follicular fluid will accumulate, and cysts will form. The treatment can be intravenous injection of chorionic gonadotropin, 5000-10000 units/time, or intramuscular injection of 10000 units. When diagnosing such diseases, Veterinary ultrasound is an important tool.

Persistent corpus luteum, caused by some pathogenic factors, can lead to the production of mummified fetuses in sows, which remain in the uterus for a long time. The corpus luteum cannot dissolve, and continuous secretion of progesterone can cause sows to not be in heat. Uterine abscess and foreign bodies can also cause persistent corpus luteum. When diagnosing, the corpus luteum on the ovary can be seen to exist continuously with little change using animal ultrasound.

The estrus of non estrus sows is irregular, and if not observed properly, they may miss the estrus period. The main factors causing this phenomenon include parity, season, weather, breastfeeding time, number of suckling piglets, physical condition and nutrition of sows at weaning, number of sows in the pen after weaning, trauma, recovery of reproductive organs, incorrect addition of hormone drugs in feed, and improper management. When the weight loss exceeds 25% and the backfat thickness measured by animal B-ultrasound is less than 15mm, it is not conducive to estrus after weaning.

The time interval between weaning and estrus mating of reserve sows is longer than that of multiparous sows. The non estrus rate of sows in summer is higher than in other seasons, and the impact of light on this is greater than that of temperature; Uterine inflammation is also an important cause of non estrus. Animal B-ultrasound examination of non estrus sows can check the condition of their follicles.