Sex

Dogs achieve their peak fertility between the ages of 12 and 15 months when they are completely physically mature. Although male dogs are sexually active all year and may father pups as young as 5 months old. Both sexes of domestic dogs reach sexual maturity, or puberty, between the ages of 6 and 12 months.

However, sexual development may be delayed in certain big breeds, with some reaching adulthood as late as 2 years. Although pregnancy is possible after the first estrus cycle, it is not advised to breed until the second period.

Puberty in male dogs often begins between the ages of six and eight months, and sexual maturity occurs after one year of age. As early as the commencement of puberty, they may be able to conceive a female dog. Similar to many other dog breeds, Collie dogs typically attain sexual maturity at about 6 months of age.

However, peak fertility often occurs between the ages of 1 and 2. Female Collies enter estrus (their menstrual cycle) twice a year, on average every six months. During her reproductive phase (which lasts just a few days), a female may produce eggs every 21 days.

Mating your Collie dogs at the right time is crucial if you want to breed them.

When a female is at her most fertile, which is during the first few days of her heat cycle, that is when mating should take place.

However, if you do not want your Collie dog to reproduce, spaying or neutering is a good option. This has the dual benefit of preventing reproduction and lowering the probability of developing certain diseases.

It's crucial to recognize the symptoms of a female Collie dog in heat. Her vulva may swell, she may have a bloody discharge, she may become more noisy, she may show an increased interest in male dogs, and she may even let male dogs mount her.

If you do not wish to breed your female Collie and you see any of these symptoms, it is best to keep her away from male dogs until her heat cycle is over.