Dogs in heat

What is a heat cycle?

A heat cycle is the fertile period of a female dog. During this time, the uterus prepares for a possible pregnancy. The female dog will have some vaginal bleeding and will attract male dogs.

When does a dog have her first heat?

The age at which a female dog has her first heat varies depending on the individual dog and breed. Female dogs of large breeds usually have their first heat between 10 and 16 months of age. In small breeds, this often happens earlier, between 6 and 10 months of age.

How often do dogs come into heat and how long does it last?

Most female dogs come into heat twice a year. Some breeds come into heat less often than others. For example, the Basenji only comes into heat once a year.

A heat cycle usually lasts around 2 to 3 weeks. During this time, the female dog is fertile for only a few days.

At what age do dogs stop coming into heat?

Female dogs do not go through menopause like humans do. They continue to come into heat throughout their lives. However, their cycles may become less regular and the frequency of their heat cycles may decrease. Their fertility also decreases as they get older.

Signs of heat in dogs

Signs that a female dog is in heat include:

• Bleeding from the vulva
• Swelling of the vulva
• Attracting male dogs
• Urinating more frequently and in smaller amounts
• Reduced appetite in some cases

During heat, a female dog may not always show all of these signs. This is known as a silent heat and can be more difficult to recognise. However, this does not mean that your female dog is not fertile.

What are the stages of a dog’s heat cycle?

The estrous cycle of a female dog consists of four phases. The heat itself consists of two phases: proestrus and estrus.

1) Proestrus

Proestrus is the first stage of a female dog’s heat cycle, during which her body prepares for the fertile phase. The vulva begins to swell and vaginal bleeding occurs. Although she may attract male dogs, she is generally not receptive to mating at this stage.

Proestrus lasts around 9 days on average, but can vary from 3 to 17 days depending on the individual dog.

2) Estrus

During estrus, ovulation occurs and the female dog is fertile. The vaginal discharge becomes lighter, and she will allow male dogs to mate with her. This stage typically lasts around 4 to 20 days.

3) Diestrus

During this stage, the female dog is no longer receptive to mating and her heat has come to an end. Even if she has not been mated, her body continues to produce the pregnancy hormone progesterone. This can lead to a false pregnancy. This stage lasts approximately 6 to 10 weeks.

4) Anestrus

Anestrus is the resting phase of the estrous cycle. Blood flow to the uterus decreases and the body stops producing progesterone. This phase lasts approximately 100 to 140 days.

Preventing heat in dogs

One way to prevent your dog from coming into heat is to have her spayed. Spaying not only prevents your dog from coming into heat and becoming pregnant, but also offers several health benefits:

• Reduced risk of uterine infections
• Reduced risk of mammary tumours
• No false pregnancies
• Reduced risk of diabetes

Tips for caring for your dog during heat

Your dog’s behaviour may change while she is in heat. She is also highly attractive to male dogs and is fertile during this time. Here are some tips for keeping your dog safe and comfortable while she is in heat:

• Keep your dog on a lead during her heat. Hormonal changes may make her more restless and less responsive to your commands, increasing the risk of her running away.
• Your dog is fertile while she is in heat, so keeping her on a lead also helps prevent an unwanted mating.
• Avoid off-leash dog areas and other busy places where dogs are walked during her heat. Your dog will be particularly attractive to male dogs, and several may try to approach her. If a male dog mates with your dog, the two dogs may become physically stuck together and cannot be separated until they naturally disengage.
• Wash or change the bedding in your dog’s bed regularly, as she may have vaginal discharge during her heat.
• You can use a dog diaper designed for dogs in heat to help prevent blood and discharge from getting onto furniture and floors.

Are you considering having a litter with your dog? Read more about pregnancy in dogs.

Do you have any questions about your dog’s heat cycle? Please feel free to contact us.