Multiple follicle development and alternating follicle development in dairy cows show that the estrus of dairy cows is short-lived, and they return to estrus quickly within 18 days, and are often unsuitable for breeding. B-ultrasound or direct examination of cattle shows that there are multiple follicles in the ovaries that develop evenly, or the follicles on both sides develop alternately. Due to insufficient secretion of pituitary follicle-stimulating hormone (FSH), B-ultrasound observation of dairy cows shows that the ovaries cannot form a dominant follicle to inhibit the continued development of other small follicles, so that multiple follicles on the ovaries develop together, and the estrogen level in the blood rises, causing estrus, but this estrus lasts for a short time, is not deep enough, and there is no ovulation of mature follicles, which often leads to long-term infertility.

Luteal insufficiency and early abortion in dairy cows, condition analysis. Low feeding level and improper management lead to poor body condition of cows, weak corpus luteum function, insufficient progesterone secretion, early absorption or death of embryos, and habitual abortion, with internal abortion being more common. This is one of the more common causes of long-term infertility in clinical practice. When using B-ultrasound for cows for clinical diagnosis, it can be found that the volume of the corpus luteum of dairy cows is reduced.

In the treatment of corpus luteum insufficiency in dairy cows (1), the injection of luteinizing hormone (LH) can effectively promote the development of the corpus luteum, strengthen the function of the corpus luteum, and improve the ability of the corpus luteum to secrete progesterone. The effect of preserving the pregnancy is definite and the prognosis is good. It is essentially different from the injection of progesterone. Although the injection of exogenous progesterone can directly lead to an increase in blood progesterone levels, it must be ensured that the medication is used for a long time to ensure the efficacy. Otherwise, the inhibitory effect of exogenous progesterone on the development of the corpus luteum will produce a drug-toxic effect, making it difficult to preserve the pregnancy. After treatment, it is necessary to use B-ultrasound for cows frequently to observe the condition of the fetus.

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