Читать книгу The Complete Book of Dog Breeding - Dan Rice - Страница 21

For about 100 to 150 days, bitches’ reproductive systems are in a quiet stage of the estrous cycle known as anestrus. One reference lists the anestrus period as two to nine months. As in other phases of the cycle, breed, condition, nutrition, and size influence the duration of anestrus. During that period, bitches exhibit no signs of heat. Their external genitalia (vulvas) remain normal in size and color, and there is no vaginal discharge. Their temperaments and dispositions are normal, and they show no sexual interest in males. It is the period of uterine rest, repair, and stabilization.

The only reproductive hormone found in the bloodstream in appreciable quantities during anestrus is estrogen. Although some consider anestrus to be a period of reproductive inactivity, the animal’s pituitary gland and ovaries are actively preparing for the next proestrus phase to begin.

As you can see, proestrus accounts for about nine days, and estrus for another nine; diestrus accounts for two months, and anestrus four or more months. Most bitches (except Basenjis) complete more or less two estrus cycles each year. The age at which cycles commence depend less on climatic conditions and geographical variations, and are more influenced by nutrition, health, and physical size.