Stages of Heat Cycle in Dogs

The heat cycle in dogs, also known as estrus is the time female dogs can mate and get pregnant. The very first heat cycle typically occurs when the female dog reaches sexual maturity, approximately at 6 to 12 months old. However, there are larger breeds that mature later (at 18 months). The heat cycle has 3 stages and you need to know the details of these stages, especially if you have a female dog.

Heat Cycle Symptoms

When the heat cycle starts, you will notice that your dog will be licking her genital area excessively. This is mainly due to the fact that the vulva is swollen and the dog tries to relive the discomfort.

Other symptoms of the heat cycle include:

  • Bleeding from the vagina, stronger during the first days and weaker as the heat cycle advances. The blood will be darker at the beginning of the heat cycle and may change color.
  • Swelling and softening of the vulva, due to the increased levels of progesterone
  • Agitation, due to the intensive hormonal activity. The dog can be more vocal than usual and will not be as obedient as before.
  • More frequent urination. The urine contains a scent that will be like a signal to the male dogs, letting them know the female is ready to mate.
  • Curving of the tail to one side, mimicking the actual mating process

The bleeding should last no more than 3 weeks and should be more intense during the first days. The dog can get pregnant only during the first 2 to 3 days after the heat cycle has started. If you want to breed your dog, you will have to ask a vet to determine the best time to do this.

Stages of Heat Cycle

When the dog has the heat cycle, she is also known to be in season. The heat cycle has 3 main stages:

  • The proestrus
  • The estrus
  • The diestrus

Each of these stages has special characteristics and you can differentiate between the stages.

Proestrus Stage Signs

The proestrus stage of the heat cycle will be manifested through bleeding and swelling of the vulva.

Your pet is likely to urinate more frequently and male dogs may be circling your home, as they feel the scent of a fertile dog.

When your pet is in heat and is in the first stage of this period, she will reject male dogs.

Estrus Stage Signs

The estrus is the part of the heat cycle starting from day 4 and may last a few days to weeks. During this stage, the dog will be willing to mate and will accept male dogs around her.

Diestrus Stage Signs

Diestrus is the last stage of the heat cycle and lasts between 4 days to 2 weeks, depending on how long the heat cycle is and how long the estrus lasts.

During this time, the dog will bleed less and will not want to mate.