Carbohydrates. If the energy level of the diet is high before and after the estrus of ewes, the ovulation rate can be increased and there is no adverse effect on the survival of the embryo in early pregnancy. One of the means to avoid this phenomenon is to use a sheep B-ultrasound machine to check the vitality of the early embryo. However, if the ewe gains weight too quickly or consumes too much energy, the conception interval will be prolonged. In order to improve reproductive performance, higher energy should be supplied to postpartum ewes to avoid excessive weight loss, but the energy intake should be gradually increased, otherwise it will cause obesity. Using a sheep B-ultrasound machine to monitor the thickness of backfat to prevent obesity is also one of the means.

Protein. Protein deficiency can cause delayed ovulation and prolonged empty period of ewes during the first estrus period. Frequent use of a sheep B-ultrasound machine to monitor the follicles of ewes is a way to prevent such situations. Excessive protein levels also have adverse effects on fertility. In addition, feeding high-protein feeds will increase the ammonia content in the rumen, which will be toxic to the embryo and may have other adverse effects on fertility.

Vitamins. The situations that lead to vitamin deficiency: First, the vitamins in the feed are completely lost due to the long storage time; second, the long-term confinement or long-term stress of the sheep reduces the vitamins synthesized by their tissues. For example, vitamin A is essential for the normal development of animal epithelial cells. If it is deficient, it will affect the fertility to some extent, mainly manifested in delayed puberty in male and female sheep, miscarriage or oligofertility in ewes, blindness or ataxia in newborn lambs, retention of placenta, high incidence rate, keratinization and degeneration of the placenta, monitoring of the uterus of ewes with B-ultrasound machines, increased incidence of metritis, decreased libido in rams, measurement of testicular volume with B-ultrasound machines, testicular atrophy, decreased number of sperm in the seminiferous tubules, and ovarian hypofunction in ewes; for β-carotene, People have found that in the case of a lack of β-carotene but sufficient vitamin A, it can cause a decrease in liver ketone levels, delayed ovulation, reduced estrus intensity, ovarian cysts, increased morbidity, delayed uterine involution, prolonged time for postpartum ovarian recovery, and increased early embryonic mortality. These reproductive system conditions are best monitored using a sheep ultrasound machine. Vitamin D deficiency can easily cause delayed estrus. Vitamin E and selenium are antioxidants, but their mechanism of action in reproduction is still unclear. There are reports that vitamin E deficiency can cause congenital malformations in lambs.