Читать книгу The Complete Book of Dog Breeding - Dan Rice - Страница 23

Canine estrous or heat cycles begin at puberty and occur throughout intact bitches’ lives until death. Spaying (removing the uterus and ovaries) ends the estrous cycles. Puberty is reached at varying ages—at five months in some toy breeds, or as late as 30 months in some giant breed individuals.

Many canine research studies use Beagles as models. In that breed, puberty is typically reached at about ten months, and it directly correlates with growth plane maturity. Since smaller breeds mature at a younger age than large breeds, it usually follows that tiny breeds experience puberty at an earlier age than giants.

We ordinarily speak of canine estrous cycles as six-month periods, but rarely do they take exactly six months to complete. The lengths of cycles not only vary between breeds, but considerable differences are common between females of the same breed. An individual bitch’s cycles are usually very predictable from year to year, but they may also vary due to health and condition influences. Some authorities speculate that the duration of lactation (length of time she nurses her puppies) may modify a particular bitch’s cycle as well.

TIP

If your bitch has not shown evidence of a heat period by two years of age, consult your veterinarian or a canine reproductive specialist.

A cute Havanese puppy looking for a playmate.

Most canine females’ estrous cycles occur more or less twice a year. Exceptions to that rule are found in the Basenji breed and in wolf hybrids. Those animals typically exhibit only one estrous cycle per year. It is interesting to note that the age a female reaches puberty relates to her body size or growth plane, but the length of estrous cycles is not correlated to body size.