The effects of heat stress on the embryo mainly change the environment in the uterus of ewe sheep, interfere with the regulation of hormones, and affect the reproductive endocrine system. In vitro and in vivo experiments of ewes have shown that the heat stress of fertilized eggs in the early stages of cleavage can increase the mortality of early embryos, which can be observed by B-ultrasound in sheep. During fertilization, the temperature of the rectum and uterus is closely related to the rate of conception, and the increase of the ambient temperature after mating will completely prevent fertilization. The regulatory response of ewes to heat stress can cause reduced blood flow to the uterus, increase the temperature of the uterus, and affect the utilization of water, electrolytes, nutrients and hormones by the uterus, resulting in increased embryonic mortality in the early pregnancy, which can be clearly seen on the B-ultrasound of sheep. "Infertility heat stress syndrome" is mainly the result of the combined action of various factors regulating the environment in the womb, the rise of reproductive organ temperature, the change of hormone balance and the decrease of reproductive blood flow may change the precise balance and physiological synchronization between the embryo and the mother, thus causing infertility.

B-ultrasound training for sheep

Heat stress has an important impact on the function of both ewe and pregnancy in the perinatal period. Some studies have found that heat stress in the late pregnancy can cause reduced blood in the goat uterus, and a reduction in placental weight and fetal growth can be found on B-ultrasound in sheep.

Cold stress affects the endocrine of the body, that is, the function of the thyroid and adrenal glands is improved, while the activity of the reproductive system is weakened or stopped, showing no estrus or no ovulation. The follicle development is very small when observed on B-ultrasound in sheep.

The reproductive organs of sterile ewes caused by environmental factors are usually normal, but do not show estrus, or the phenomenon of estrus is slight; Sometimes, although there are external manifestations of estrus, ovulation is not achieved, which can be observed with B-ultrasound in sheep. Once the environment changes or the ewe ADAPTS to the local climate, reproductive function can return to normal.

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