When breeding dogs mate naturally, the mating time of female dogs should be determined according to the specific situation of their estrus, and cannot be simply calculated according to the estrus time (because some female dogs are not discovered until a few days after estrus). The specific method is to observe that the blood flowing out of the female dog's vulva becomes light red and slightly sticky, the vulva is swollen and shiny, and its base becomes soft. At this time, mating can be carried out, which is about the 9th to 13th day of estrus, slightly earlier for older dogs and slightly later for young dogs. This is a clinical observation method for identifying estrus and ovulation. Animal B-ultrasound machines can also be used to check the development of follicles to determine estrus. For some dogs that have difficulty in observing external reproduction, laboratory examination methods (such as vaginal epithelial cell microscopy and blood progesterone determination methods, etc.) and laparoscopic observation of uterine and ovarian changes, animal B-ultrasound machine ultrasound examination methods, and estrus test methods can also be used to determine the best breeding time.

The estrus of female dogs is not limited to time and season, and it occurs all year round. This requires our breeders and technicians to be responsible for the management of breeding dogs. Each female dog should be carefully observed, and it is best to use animal B-ultrasound examination. However, the estrus of female dogs has a certain regularity, that is, there is an estrus cycle, and the average time of this cycle is about 180 days. This is conducive to the breeder to grasp the estrus time of female dogs. The approximate time of the next estrus can be calculated based on the time of the last estrus. If you want to make an accurate judgment, you can use animal B-ultrasound to check the follicles. Breeders strengthen their observation of dogs and predict their estrus dates. Technical personnel carefully check estrus female dogs, observe and grasp the signs and progress of estrus, or use animal B-ultrasound to check follicles to determine the estrus status, and adopt appropriate breeding methods in time according to the breeding plan and the previous breeding situation of the dog. Artificial assistance is provided for dogs that have difficulty in free mating.