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As with most domesticated species, one of the first and strongest effects seen from selective breeding is selection for cooperation with the breeding process as directed by humans.
The ability of female domestic dog to come into estrus at any time of the year and usually twice a year is also valued. The amount of time between cycles varies greatly among different dogs, but a particular dog's cycle tends to be consistent through her life. This is also called in season or in heat.
Conversely, undomesticated canine species experience estrus once a year, typically in late winter.
Becoming fertile (menarche)Most dogs come into season for the first time between 6 and 12 months, although some larger breeds delay until as late as 2 years.
Like most mammals, the age that a bitch first comes into season is mostly a function of her current body weight as a proportion of her body weight when fully mature. The different rates of maturation are responsible for the menarche, not the chronological age.MenopauseDogs do not experience menopause, although their cycles will become irregular and fertility becomes unpredictable. |
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