The neonatal period and weaning period are two critical periods for the growth and development of mammals. Lambs transition from a sterile, safe, stable, and nutrient rich environment in the maternal uterus to a complex external environment, resulting in significant changes in various physiological and biochemical indicators of their body. When the lamb is in the uterus of the ewe, it can be seen on ultrasound that the digestive system is not very complete, especially the structure of the stomach.

The developmental level of newborn lambs is far from adapting to the drastic changes in the environment, so breastfeeding is particularly important in the growth, development, and acquired immunity of lambs. Modern intensive animal husbandry also requires early weaning to shorten the production cycle and reduce production costs. Therefore, during weaning, sheep's digestive system should be tested using B-ultrasound to see if it has fully developed.

There is no unified regulation on the early weaning time of lambs, and there are mainly three methods: first, determining the weaning time based on the age of the lamb, mainly weaning at one week of age, and then using substitute milk for artificial lambing; Most of them are weaned at 6-7 weeks of age, and after weaning, they can be fed with plant-based feed or grazed. Of course, this method is based on experience. A good method is to examine the gastrointestinal tract of lambs using B-ultrasound, and then determine the time based on the imaging of the Sheep using B-ultrasound. From the perspective of gastrointestinal function development in lambs, at 7 weeks of age, they can effectively utilize feed like adult sheep

This is the only way to improve production capacity, which often leads to growth retardation, even stagnation, low immune function, and diarrhea in young livestock during the neonatal and weaning periods, collectively known as weaning syndrome.