Due to individual differences, young cows need to discharge all their lochia after delivery, but the end time of lochia discharge is basically the same, and all of them are discharged at 18 days.

The process of endometrial regeneration and uterine recovery in the postpartum period of cows is a gradual process. This causes different changes in the postpartum period and different lengths of postpartum recovery. According to veterinary B-ultrasound observation, it usually takes 30 to 45 days for the uterus to recover and complete the complete regeneration of the endometrium.

According to veterinary B-ultrasound observation, although the estrus performance of young cows after delivery has a certain regularity, due to the influence of internal and external factors, there is a lack of obvious characteristics and regularity in the performance, and it must be analyzed specifically based on the comprehensive situation.

After the delivery of young cows, veterinary B-ultrasound observation shows that there are follicles developing on the ovaries, but due to individual differences, the time of the first estrus of young cows after delivery is different, and there are great differences between different individuals. Young cows show estrus from one week to 23 days after delivery.

The time of the first estrus cycle of young cows after delivery is different. The average normal estrus cycle is 21 days, ranging from 17 days to 26 days. The estrus cycle of young cows is 19-33 days, and some cows have longer estrus cycles.

The veterinary B-ultrasound images show that the ovaries of young cows are particularly small, firm, and hard after giving birth. Small, medium, and large follicles all show different degrees of growth and development. But before the first estrus, the ovaries become softer, and the area and thickness of the ovaries also increase.