The estrus cycle is a set of physiological changes in a female mammal that occur prior to ovulation and prepare her for mating and reproduction. The estrus cycle is commonly known as the menstrual cycle in primates, including humans, and the heat cycle or oestrus cycle in other species.
Dogs
Dogs are seasonal polyestrous, meaning they have multiple heat cycles per year but only at certain times of the year. The estrus cycle in dogs typically lasts about 21 days, but can vary from 14 to 30 days.
The estrus cycle is divided into four stages:
* Proestrus: This is the first stage of the estrus cycle and is characterized by swelling and reddening of the vulva and a bloody discharge. Proestrus typically lasts for 9-10 days.
* Estrus: This is the second stage of the estrus cycle and is characterized by the female being receptive to mating. Estrus typically lasts for 5-7 days.
* Diestrus: This is the third stage of the estrus cycle and occurs after ovulation has occurred. Diestrus typically lasts for about 14 days.
* Anestrus: This is the fourth and final stage of the estrus cycle and occurs when the female is not sexually receptive. Anestrus typically lasts for about 4-5 months.
Signs of heat
There are several signs that a dog is in heat, including:
* Swollen and reddened vulva
* Bloody discharge
* Increased urination
* Increased restlessness
* Increased affection towards people
* Attempting to mount other dogs
Breeding
Dogs should not be bred until they are at least 18 months old and have had at least one heat cycle. If you are planning to breed your dog, it is important to talk to your veterinarian first to make sure that she is healthy and fit for breeding.