A female dog’s heat cycle has a predictable pattern, but no two dogs go through heat cycles the exact same way. Any time the dog is in heat, she can get pregnant, but there’s the sweet spot for the most fertile days, which generally happens just as the bleeding starts to taper off.
It’s important for a responsible breeder to be aware of every stage during the heat cycle to care for the health and safety of the female dog. Keep notes as there’s going to be a little nuanced activity during this time, in addition to clear key indicators of heat. You are going to be very busy, so the notes help with this heat and the heats to come.
The Stages Of Heat
There are three main stages of heat – proestrus, and estrus. This is the time of “coming into season” for a female dog. There are key indicators each stage is happening.
Proestrus: 7-10 Days
This stage is where the female dog’s body is preparing for reproduction. For the owner, this is the first sign of heat. The vulva on the dog will swell to several times its normal size. A discharge will start, generally clear, and then turn shades of brown or red. Some dogs are very good self-cleaners, so it’s important to realize the dog might be cleaning herself before you even see a mess. This is also a good time to have those doggy diapers handy if your dog is a heavy bleeder.
She’s going to urinate more frequently, so keep that leash handy and don’t punish any accidents. This stage is the closest to what you’d think of a human female’s menstruation. Keep in mind she’s urinating as her calling card to alert any males in the area that she’s available for breeding. That urine is loaded with hormones and pheromones that attract male callers.
The female dog, even though she’s bleeding, generally won’t let another dog mount her at this time. She is still somewhat fertile during this stage, but it’s not the most fertile time.
Estrus: 5-10 Days
This stage is the most fertile, but there are key dates within estrus you can only measure by looking at hormone levels.
It’s imperative to check hormone levels during this time. You are looking for estrogen surges and the Luteinizing hormone (LH). When the LH surge happens, it is the first day of ovulation. Progesterone is also increasing during this time. If those hormones and names are overwhelming, your veterinarian can help you through. You’ll be seeing them a lot during the breeding season.
During this phase, the female dog might still be bleeding or have some kind of discharge, but it will most likely get lighter and less common. A more watery discharge indicates she’s ripe for breeding and most fertile.
A physical way to notice the LH surge is happening is the female dog will start “flagging.”
“Flagging” means the female dog is wagging her tail high and to the side to allow easier access to the genital area.
This isn’t just a regular wagging of the tail. The tail might be high and wagging, or the entire backside could waggle to open up the genital area to male callers. The female dog will stand purposefully and flag. Please note the first day she does this, as 2-3 days later she’s ready to breed and at her most fertile point.
Those notes you are taking will come in handy because most dogs will follow their individual pattern each heat cycle. The only caveat to this is the first heat can be lighter or more volatile in terms of cycle lengths.
This is the stage where the female is no longer wanting or accepting any male attention. She might even get aggressive at dogs that try to mount her. She’s back to discharge that’s thicker and redder.
Her hormones are also getting back in check during this time with estrogen lowering while progesterone increases before eventually leveling out.
Semen from a male dog can live inside the reproductive system of a female dog for up to a week, so pregnancy can result after you think the heat is over. This is why it’s critical to keep female dogs on a leash and away from male callers if you don’t want a litter.
For a breeder, this is also a time to start medically and physically caring for a pregnant dog.
What Other Conditions Do I Need to Know about in the Vulva?
The discharge from a dog in heat is not in any way connected to its urine stream. While the liquid comes from the same area, they are two different critical functions of a female dog.
If you notice a bloody discharge coming from a dog that is not in heat, then you need to see the veterinarian. It could be an infection or blood clotting disorder.
Certain breeds can be impacted by Vaginal Hyperplasia and Prolapse. This is when a mass protrudes from the vulva. A novice breeder might think this is the vulva swelling because of heat, but it’s a real medical condition that needs professional attention. This mass could also make itself noticeable during heat because the vulva is already swelling and reveals the problem.
Dogs more prone to this condition are:
- German Shepherds
- American Pit Bull Terriers
- Springer Spaniels
- Walker Hounds
If a dog has this condition, it probably isn’t going to mate even if she goes into heat. Most cases of vaginal hyperplasia and prolapse just require the owner to keep the area clean and look for any changes in size and color.
If you notice blood in the urine stream, that is most likely a kidney or urinary tract infection. It’s not connected to the heat cycles.
Do Male Dogs Have Any Discharge or Reproductive Cycle?
Male dogs can reach sexual maturity around 6 months of age, the same as females. If you are raising a stud, the optimal amount of semen is 10 million sperm per pound of body weight.
Any discharge that comes from a male dog’s privates during any point of life should require a trip to the vet.
Male dogs don’t go through any heat cycles. Once they are sexually mature, they will be ready for any female dog in heat. They can smell a female dog in heat from up to three miles away and will take aggressive means to get her by natural instinct.
I Don’t Want My Female Dog to Go Through Heat
You might think, “Wow. That’s a lot. How can I avoid going through a heat cycle with my favorite girl?”
New research suggests it’s optimal for female dog health to wait for one heat cycle before having them spayed. This can allow the growth plate to close and let the dog real full maturity. If spaying is done too early, there could be bone and joint issues down the road. However, compared to the pet overpopulation issues nationwide, most animal shelters will fix a dog before it can be adopted.
It certainly isn’t a death sentence to spay them early, it’s just a decision you should make with all the information available.
Stages of heat: https://www.merckvetmanual.com/dog-owners/routine-care-and-breeding-of-dogs/breeding-and-reproduction-of-dogs
AKC Heat Cycle Info: https://www.akc.org/expert-advice/dog-breeding/how-long-are-dogs-in-heat/
More about heat and bleeding patterns: https://www.akc.org/expert-advice/dog-breeding/when-dogs-in-heat/
Semen and ovulation timing: https://www.akc.org/expert-advice/training/ovulation-timing-in-the-female/
Details of a dog “period”: https://www.akc.org/expert-advice/health/do-dogs-have-periods/
How long they are in heat and fertile: https://www.akc.org/expert-advice/dog-breeding/how-long-are-dogs-in-heat/
Swelling in the vulva that isn’t normal: https://www.petmd.com/dog/general-health/dog-vaginal-health-guide-everything-you-need-know
Hyperplasia and prolapse: