Dogs In Heat: Understanding the Cycle

Dogs in heat go through various cycles, which can vary in length. When a dog reaches puberty, that's when she begins her estrus (or heat) cycle. Many times the onset of puberty, and the length of the estrus cycle depends on the breed and size of the dog.

A dog's heat cycle generally occurs twice a year, from January to March and August to October. You can better understand the stages of estrus by reading the following information:

The Four Cycles of Dogs in Heat

The typical stages of heat appear in four phases, and the length of these cycles may fluctuate between dogs. Still, even the same dog can possess considerable variations in her cycles over the course of her lifetime.

The cycles of estrus are as follows:

  • Proestrus is a 10-day period where a dog will have spotting, or bleeding, from her vaginal area.
  • Estrus lasts for 5 to 9 days. At this stage, a dog is ovulating and will accept a mate.
  • Diestrus lasts for 6 to 10 weeks. Many hormonal changes will take place in the dog, and her uterine walls will thicken.
  • Anestrus usually lasts for 15 weeks. Your dog won't have any hormonal activity, produce milk or possess an interest in mating.

How to spot a dog in heat:

  • Swelling and enlargement of the vulva and vagina.
  • Vaginal discharge: beginning as pink liquid then progressing to a bloodier fluid.
  • Marking her scent by leaving small amounts of urine.
  • Male dogs trying to get near your dog.

Dogs in Heat: False Pregnancy and Spaying

A dog that does not become pregnant during the diestrus stage can experience false pregnancy. However, she will have symptoms of pregnancy, such as enlarged mammary glands and milk production. During this time, a dog may moan, become needy and show possession over her toys.

A common way to control a dog in heat is to have her spayed. A spayed dog will not show signs of estrus. If you want your dog to mate, she may be given hormonal medications to temporarily prevent her heat cycle from progressing. Additionally, a female dog does not experience menopause in the traditional sense. She will go through heat during her entire lifetime. However, the length of time between heat episodes will increase as she ages.

Understanding When to Breed Your Dog

A female dog is able to become pregnant during the estrus stage. Pet owners may have trouble distinguishing between the proestrus and estrus cycles. It may be challenging to determine which stage of the cycle a dog is at by her behavior alone. If a dog is not accepting a male, or cannot get pregnant, you many want to monitor her heat stages more closely.

You can also have your dog tested to better understand her cycles, and find out when is the ideal time for her to reproduce. A vet can help you figure out if your dog is at the correct breeding stage. The animal professional will likely perform a vaginal cytology exam, or take blood samples to check your dog's progesterone levels.