Abnormal heat cycles in female dogs

We all love to plan and trust that everything is predictable. Mother Nature likes that, too; however, she’s not always able to deliver. While most dogs go into heat twice a year and stay in heat for 21 days, abnormalities do occur.

This article gives a summary of possible abnormalities in the heat cycle of female dogs. You will learn what is silent heat, absent heat, split heat, among others.

female dog in autumn leaves
Photo by Jaroslav Silhan.

IMPORTANT: the heat cycle can often be disrupted by serious health issues. Therefore, you should seek for a veterinary help if one of the following occurs.

Absent heat

As the name implies, absent heat is when a dog does not come into heat, even though it should. It can occur in young dogs who have not yet come into their first heat or in mature dogs who had cycled regularly before but suddenly stopped cycling.

Reproductive system diseases are the most common cause of absent heat, and a veterinarian should examine the dog.

Absent heat can also occur due to a medicine used for treating other conditions, especially if the medicine involves hormonal therapy. Talk to your veterinarian, but in most cases, the heat cycle should eventually return to normal if the treatment is applied correctly.

Poor general health in a dog can also trigger a skipped heat cycle to conserve energy.

Absent heat is often confused with the dog not being fully mature yet and so-called silent heat.

Silent heat

Silent heat happens when the dog is in heat, is receptive, can get pregnant, but does not show heat signs. Sometimes males are not attracted to dogs in silent heat, but they often are.

In most cases, signs are present but are so weak that dog owners miss them. These are the lucky ones because many people struggle with their dog’s behavior changes during the heat.

It’s not uncommon for smaller dog breeds to have one or two silent heats before apparent symptoms appear.

Silent heat should not be confused with the owner’s inexperience at noticing symptoms. Bloody discharge and the swelling of the vulva may easily go unnoticed or get mistaken for something else. Especially if the dog is orderly about her hygiene practices.

If a dog is in silent heat, the only way to confirm the heat cycle is to take the dog to the vet who will perform vaginal secretion and blood tests.

Split heat

Split heat is when the heat cycle begins, but then stops before the second phase, standing heat, begins. It commonly occurs in young dogs during their first heat because the hormonal systems are unable to induce ovulation.

In the case of young dogs, there should be no worries, and a normal heat cycle is likely to reoccur within two to ten weeks. On the other hand, split heat in a mature dog should be examined by a veterinarian.

Prolonged heat

Dogs usually stay in the heat for 21 days. Anything longer than that is considered to be a prolonged heat.

Prolonged heat is a relatively frequent occurrence, and there is nothing to be concerned about in younger dogs. However, if prolonged heat occurs when the dog has reached maturity (2-3 years), a veterinary examination is necessary.

Most often, mature dogs stay in heat for too long because of an ovarian cyst or tumor. While it sounds unfortunate, when diagnosed early, the reproductive organs usually can be surgically removed with no further health hazard.

Too frequent cycling

Most dogs come into heat twice a year, but it is common for dogs to cycle three or four times per year.

There should be no worries if this happens in young dogs; their cycling frequency must stabilize as they mature. However, if your dog regularly cycled before, but suddenly started coming into heat more often, it’s best to take her to a veterinarian.

Note that if you are into breeding, some of those “extra” heats may be infertile since the dog’s body needs proper time to recover from the previous cycle.

Too rare cycling

Dogs usually come into heat twice a year (with exceptions for some breeds). At the same time, it is still common if a dog does not go into heat up to a year or a year and a half. Especially for young or old dogs.

Everything more extended than a year requires a medical examination, especially if your dog has had a regular heat cycle before. Unfortunately, there are too many possible causes to make speculations on a website, and you must visit a veterinarian.

This article is a part of a series about female dogs in heat.