When Do Dogs Go In Heat?

If you’re wondering when do dogs go in heat, you’re not alone. Many pet owners have questions about their dog’s reproductive cycle. Here’s what you need to know.

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Dogs go into heat when they reach sexual maturity and are ready to mate. The average age for dogs to first go into heat is six to twelve months, although this can vary depending on the breed. Small breeds tend to go into heat earlier than large breeds.

The length of time a dog is in heat also varies. Small breeds may be in heat for only a week or two, while large breeds may be in heat for three weeks or longer.

During the times when your dog is in heat, she will be more alert and interested in smells. She may also urinate more frequently to mark her territory. You may notice her vulva is swollen and red, and she may bleeds lightly. Dogs in heat also tend to be more affectionate than usual and want to spend more time with their owners.

What is Heat?

Heat, also known as estrus, is the time when a female dog is receptive to mating. This period usually lasts between 18 and 21 days, but can be shorter or longer in some cases. During this time, the dog’s body prepares for pregnancy by releasing eggs from the ovaries and thickening the uterine lining. If the dog is not mated during this time, she will go into “false pregnancy,” which is when the eggs are not fertilized and the dog’s body still believes it is pregnant.

The Heat Cycle

The estrus cycle or “heat” of a female dog lasts approximately 18 days. The first half of the cycle (proestrus) lasts 9 days on average. This is when the female’s body is preparing for ovulation and she will have a bloody vaginal discharge. During proestrus, the female may also seem lethargic, gain weight, and her nipples will become pink and enlarged. You may also notice your dog has mood swings and is more affectionate than usual.

The second half of the heat cycle is called estrus and lasts an average of 9 days. This is when the female is actually in heat, meaning she is ovulating and can become pregnant. During estrus, the bloody vaginal discharge will turn light pink or brown in color. Your dog’s vulva will also swell and you may see her “flagging” her tail more frequently – raising her hind end in the air when she wags her tail. Females in heat also tend to urinate more frequently to help spread their scent and attract males.

Signs Your Dog is in Heat

As a dog owner, it’s important to be aware of the signs that indicate your canine companion is in heat. Being able to recognize these symptoms will help you better care for your pet and make informed decisions about breeding.

Most dogs will go into heat twice per year, although this can vary depending on the breed. Smaller dogs may go into heat more frequently, while larger breeds may only cycle every 18 months or so.

The first sign that a dog is in heat is usually a change in behavior. She may become more affectionate than usual, or she may seem agitated and restless. You may also notice your dog licking her genital area more frequently.

As the cycle progresses, you’ll notice physical changes as well. The dog’s vulva will swell and she may have a discharge that ranges from light pink to bloody. The bloody discharge will usually last for nine days to two weeks and will taper off towards the end of the cycle.

If you’re not planning to breed your dog, it’s important to keep her away from male dogs during this time. Unwanted pregnancies are common in unspayed female dogs, even if they’ve never had contact with a male dog before. If you think your dog has mated, contact your veterinarian immediately so they can determine if a pregnancy has occurred.

How Long Does Heat Last?

On average, heat lasts for 18 days, but this can vary based on the breed of dog. Small breeds tend to go into heat for shorter periods of time than large breeds. The first heat usually occurs when a dog is between six and twelve months old, but this can also vary based on the breed. Some smaller breeds may have their first heat as early as four months old, while some larger breeds may not have their first heat until they are eighteen months old or older.

How to Care for a Dog in Heat

Dogs go into heat usually twice a year, although this varies depending on the breed. During this time, your dog’s behavior may change and she may be more prone to certain health problems. Here are some tips on how to care for your dog during her heat cycle:

1. Keep your dog clean. She may be more likely to develop urine infections during this time, so make sure you clean her thoroughly after she goes outside.

2. Avoid strenuous activity. Your dog’s body is going through a lot of changes and she may tire easily, so it’s best to avoid excessive exercise during this time.

3. Be mindful of her diet. Your dog’s appetite may change during her heat cycle, so make sure you are feeding her a balanced diet that meets her needs.

4. Watch for signs of discomfort. If your dog seems to be in pain or is uncomfortable in any way, consult your veterinarian for help.

Spaying or Neutering

The best time to spay or neuter your dog is before the first heat cycle. For most dogs, that’s between 4 and 6 months old. If you wait until your dog is older, you’ll still need to take special precautions during her first heat since that’s when she’s most likely to get pregnant.


-How often do dogs go into heat?
-What are the signs that my dog is in heat?
-How long does the heat cycle last?
-What can I do to help my dog during her heat cycle?
-Can I spay my dog while she is in heat?


Dogs go into heat usually twice a year, though this can vary depending on the breed. Smaller breeds tend to go into heat more often than larger breeds. The best way to determine when your dog will go into heat is to ask your veterinarian.

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