Understanding silent heat in the bitch

If your female dog is unspayed and in normal reproductive health, she will come into season regularly if infrequently, usually just once or twice a year. Knowing when your bitch is likely to come into heat is important for the owner of an unspayed dog, both so that you will know when the time is right to mate her if you intend to breed from her, and to keep her away from male dogs if you do not!

However, if you know that your dog should be approaching her season, but things run late and ultimately, it seems as if she has not come into heat at all, this can be very confusing! While it is not impossible that a female dog will skip a season now and then, there is another possibility: a silent or “dry” heat.

A silent heat is when your bitch goes through her season, but it is virtually asymptomatic, and does not come accompanied by the normal signs of heat, such as changes in behaviour, physical changes, and the urge to breed, displayed both by the bitch and any unneutered male dogs that she comes into contact with.

If you own an unspayed bitch, it is wise to make yourself aware of the possibility of a silent heat, the potential causes for it, and how to identify it, so that you can be aware of it. Read on to learn more.

The lack of the normal symptoms of a season

How each bitch behaves and shows symptoms of her season can vary from case to case; in some it is obvious and very pronounced, while in others, it can be hard to tell, even if the bitch is going through a genuine season.

Some bitches do not change in behaviour or temperament during their heat cycle at all, and may have only a very light discharge with little to no swelling of the vulva, and this is perfectly normal for some bitches. This does not mean that your bitch is necessarily going through a silent heat, but simply that her seasons are very asymptomatic.

Reactions to male dogs

Even if you are not aware that your bitch is in season because the effects of it are very muted, if your bitch is indeed in season, male dogs in the locality will very much be aware of it! If male dogs start hanging around your house, or make a beeline for your bitch when out on walks and display a heightened level of sexual interest in her, the chances are that she is in heat, but that you are simply not aware of it. If this is not the case, then a silent heat might be the reason.

Silent heat or skipped heat?

It is important to differentiate between a silent heat and a skipped heat cycle, and both instances are equally likely to happen, adding to the confusion!

Your bitch may potentially be more likely to miss a heat cycle if she has one of a certain set of medical conditions, such as hypoadrenocorticism, hyperadrenocorticism, or hypothyroidism, so if your bitch does miss a heat cycle and displays any other symptoms, it is worth getting her checked out by the vet just in case.

Bitches that are underweight or very thin, or that have recently lost a reasonable amount of weight may also be apt to miss a heat cycle altogether, which is also worth bearing in mind.

Differences between breeds

While the vast majority of female dog breeds and types are apt to come into season regularly every six or seven months, some breeds are known to only come into season around once a year on average. The Tibetan Mastiff and the Basenji are just two such breeds, so it is wise to look up the normal parameters of your dog breed’s heat cycle before you start to wonder if something is amiss.

Veterinary testing

If you suspect that your bitch has skipped a heat cycle or is going through a silent heat, it is well worth getting your vet to investigate, in order to rule out any underlying problems. Your vet can run hormone tests on your bitch’s progesterone levels, in order to find out if they have missed a season or are going through a silent heat, in order to build up a complete picture of what is happening.

Inducing a season

Often, unspayed female dogs that are housed together will come into season around the same time, and housing a bitch that is apt to skip a season with another bitch in heat can actually serve to induce the heat cycle in the other bitch, should this be appropriate.

This is not an exact science, but this process is often used by professional dog breeders to bring a bitch into season for breeding if she appears to be late in her heat cycle or about to miss a season.