Читать книгу The Complete Book of Dog Breeding - Dan Rice - Страница 20

The third stage of canine reproductive cycles is known as diestrus. In literature from prior years, this phase was called metestrus, and had a slightly different academic definition. For practical purposes, metestrus and diestrus are synonymous. Diestrus lasts about 60 days. It is currently defined as the period extending from the last day a bitch will accept a male until the termination of pregnancy. If she is not mated, a female’s outward appearance during diestrus is indistinguishable from anestrus (see below).

Cavalier King Charles Spaniel pups mature quickly and are extremely energetic.

Because ovulation is spontaneous in the bitch, it is not signified by outward signs, receptivity, or male interest. Once ovulation occurs, the follicles from which eggs were discharged begin to recede. Diestrus is under the influence of the hormone progesterone, which originates from those corpora lutea (plural of corpus luteum). Progesterone is often called the hormone of pregnancy, and is responsible for the maintenance of the uterus and the fetuses implanted and growing therein.