Canine Reproduction
Puberty is usually reached by 6-7 months of age (range 4-22 months), however there is wide individual and breed variability. Small breeds tend to have a first heat at 6-10 months of age, but larger breeds may not begin to cycle until 18-20 months old.Bitches are described as mono-oestrus since they have only one oestrus during each breeding season.
Seasonal activity may be slightly increased during the period of February to May, but essentially bitches commence cycling, breed and whelp throughout the year. The normal inter-oestrus interval is 5-10 months.
Feline Reproduction
Under normal climatic conditions queens are seasonally polyoestrus. However, under modern housing conditions queens frequently cycle throughout the year. The sequence of events is pro-oestrus followed by oestrus and metoestrus.On average, domestic cats reach puberty by 6-9 months of age. Ovulation is not spontaneous. It is induced naturally by mating or artificially by stimulation of the vagina and cervix or by hormone administration.