Understanding Your Dog's Heat Cycle

What Does “In Heat” Mean?

Heat is the female dog’s body preparation for breeding and the possibility of producing a litter.  It is sometimes called “in season.”  While you may never intend on breeding your female dog, it is good to know what is happening in her body.  Understanding the process can allow you to prepare for breeding or learn how to prevent an unwanted pregnancy.

According to the University of Georgia College of Veterinary Medicine, the “heat” cycle is broken into four stages:

Proestrus -  This stage lasts approximately nine days.  The female’s level of estrogen increases and she starts to exhibit signs like mood changes (doggie PMS), sudden interest from males, possibility of swollen nipples, and the vulva starts to swell.  Pinkish-red blood discharge will also start the first week.

Estrus - This stage also lasts about nine days.  Estrogen levels drop while progesterone levels rise.  This is when ovulation begins.  Ovulation is when a series of eggs will be released from her ovaries and become available for fertilization.  The discharge turns a tanish color and she begins to be receptive to the male’s attempt to breed with her.  She will also do what is called “flagging.”  This is when she stands still while the male investigates her and she holds her tail up and wags it side to side to make sure he catches her scent.  This is when she will most likely become pregnant.

Diestrus - This stage lasts about two months.  The progesterone levels are still elevated, but the female will no longer be receptive to a male’s attempts to breed with her.

Anestrus - This is the resting stage and lasts until the female comes into heat again.

When Will My Dog Start Going Into Heat?

Most female dogs first go into heat when they are about six months old.  However, some females can go as long as one year to 18 months, and large breeds can start as late as two years old.  After your dog’s first heat cycle occurs, it will take place once every six to 12 months.  There are times that females can go into heat every four months, but they are not always fertile cycles.

How Do I Care for My Dog When She’s In Heat?

Caring for your dog while she’s in heat is simple, but you do need to keep a close eye on her.  Males can detect her scent from blocks away and breed with her even if you don’t want them to.  Be sensitive to your girl, as she may not feel too great during the Proestrus stage.

Never give your girl a bath until she is completely finished discharging.  This will ensure that her cervix is completely closed and she will be less likely to get a vaginal or uterine infection from the bath water.

Also, prepare for the heat cycle by purchasing a pair of pants that resemble a diaper from your local pet store.  For an inexpensive alternative, you can purchase a pair of small women’s or girls underwear, cut the sides and customize them to your dog’s hindquarters by tying them like a bathing suit bottom.

Spaying is another alternative if you don’t plan on breeding your dog.  This will eliminate her heat cycle altogether, and you will never have to worry about her having an unplanned litter.

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Image via: She Knows