After the ewe reaches sexual maturity, the ovaries ovulate periodically, and with each ovulation, the reproductive organs also undergo periodic series changes. Usually, the initial stage of ewe sexual behavior is called estrus, and the time between ovulation is called estrus cycle. The estrus cycle of sheep is 16- 19 days, with an average of 17 days. The estrus cycle of goats is 18-2 1 day. 20 days on average.

1. In the early estrus, the corpus luteum in the ovary shrinks and new follicles begin to develop, but they are still small. At this point, the ewe has no sexual desire.

2. During estrus, ewes are sexually excited and their follicles develop rapidly until they mature and ovulate. Increased uterine peristalsis, vaginal congestion, flushing, increased gland secretion, cervical opening, vaginal discharge of mucus, labial swelling. Mental excitement, emotional anxiety, constant Cleisthenes barking, climbing the wall, pushing the door, or standing in the circle constantly swinging the tail, loss of appetite, leaving the group when grazing, like to get close to the ram, accept climbing, and climb other sheep. This period is suitable for breeding, and breeding should be timely. Generally speaking, the average estrus of sheep is 30 hours, and that of goats is 40 hours.

3. After ovulation in the late estrus, the corpus luteum in the follicle begins to form. During estrus, a series of changes in the reproductive tract gradually disappeared, restored to its original state, and sexual desire decreased significantly.

4. During the period from the beginning of estrus to the next estrus, the mental state of ewes is normal.

5. Postpartum estrus sheep can still be estrus if they are in the breeding season. The postpartum estrus time of sheep is generally 30-59 days, with an average of 35 days; Goats average 20-40 days; Dairy goat 10- 14 days. Small-tailed Han sheep also have the property of hot mating, that is, they can mate within 2-5 days after delivery.