But what is “heat” and why does it affect dogs? The reason your dog is acting in a way that is hard to bear is due to her reproductive cycle, often referred to as the “heat” cycle. The heat cycle is part of your dog’s reproductive system. The function of the heat cycle somewhat resembles a woman’s monthly menstruation, though it is slightly different and, luckily, dogs come in heat only twice a year.
So, how does the heat cycle differ from the human menstruation cycle? For humans, menstruation occurs after ovulation and only if the ova has not been fertilized. Dogs, however, are considered “in heat” before ovulation, and their cycle actually makes them slightly anxious to mate, causing behavioral changes like restlessness.
The complete cycle consists of four phases: Proestrus and Estrus, when the dog is referred to as being “in heat,” and Diestrus and Anestrus, when the dog is not in heat.
Don’t let yourself be confused about these fancy words—they all come from the Greek root “oistros,” which means frenzy. The prefixes pro-, di-, and an- mean “before,” “second,” and “not accordingly.” Thus designating times when your dog is almost in frenzy, in frenzy (no prefix), once again in frenzy, and not in frenzy.
Each part of the heat cycle generates different hormones that influence your dog, working together to help make the miracle of the birth happen…or not happen.
- Proestrus, or before being in frenzy, is a preparatory stage which gets your dog ready to be in heat. A red discharge from the vulva usually appears at this stage.
- Estrus, or true heat, will likely be the most difficult part of the heat cycle for you. This is when ovulation occurs and the uterus is receptive to implantation. In this stage, your dog will be extremely attracted (and attractive) to males. Even if you consider your dog to be extremely well trained, she will likely find it difficult to listen to your commands in this stage. This is also the phase when your dog is able to become pregnant.
- Diestrus is the part of heat that is responsible for sustaining pregnancy in the event that a successful mating occurs. As the prefix di- suggests, this is a second frenzy, though your dog will not actually be frenzied during this time. The start of this stage will be evident when a female refuses to “stand” for mating. No matter if a female has become pregnant or not, her body produces hormones to sustain the growth of the fetus which cease only when diestrus is over after one to two months.
- Anestrus is the last part of the heat cycle in which the reproductive system takes a rest and gains strength to undergo the next heat cycle. This normally means the dog is not in heat and can last for several months, after which the cycle begins again, and the dog will go into proestrus once more.
So what now? If you have noticed some unusual behavior or discharge, your dog is likely at the stage of proestrus or estrus. You’ll have to be tough and hold in there though, because once started, the cycle cannot be interrupted. As mentioned before, the best option to prevent your doge from going into heat is to spay her, however, if heat has already started, your must wait for it to end before doing the surgery. In order to help you with the struggle in the meantime, here are several tips to help you on your way.
This article is a part of a series about dogs in heat.
Next up: At what age do dogs come in heat?
