A Guide to Dog Heat Symptoms

Dog heat occurs on a cycle that averages around twenty-one days. Your dog's heat cycle brings with it many signs and symptoms; learning to recognize them can make it easier to plan or prevent the birth of puppies. Here's how you can tell which part of the heat cycle your dog is in.

Proestrus: The First Week of Heat

The first week of your female dog's heat cycle is known as proestrus. This period lasts from seven to ten days, with most dogs experiencing this stage of the heat cycle for about nine days. Here are some of the signs you may notice during this stage of your dog's heat cycle:

  • Personality changes may cause your dog to become more affectionate and clingy, or she may become grumpy and aloof. Some dogs may act completely different from the way they normally do; in others, the changes in personality may be less pronounced, or nonexistent.
  • Appetite changes mean your dog may experience decreased appetite during proestrus, though more rarely, she may become hungrier. Some dogs may begin raiding trash cans during this period; others may go off their food entirely.
  • Swelling of the vulva, like other symptoms, varies in extremity from one dog to another. Vulva swelling may become quite noticeable; you can find your dog's vulva located in the pelvic opening, just below her anus.
  • Bloody discharge from the vulva may be light during the first few days and grow heavier as the week goes by; you may wish to purchase dog diapers or pads to catch the discharge during your dog's heat cycle.
  • Tail tucking is the result of an instinctive desire to protect the vulva.
  • Your dog may also urinate more frequently during this part of the heat cycle.

Estrus: The Second Week of Heat

The second week of your dog's heat cycle is known as estrus. This is the period during which your female dog's ovaries are releasing eggs for fertilization and she becomes fertile. Signs of estrus include:

  • The bloody discharge lightens from bright red to a pinkish-tan color.
  • Vulva swelling subsides, making the vulva soft enough for penetration.
  • During estrus, your dog will stop tucking her tail. Instead, she will begin waving it flirtatiously in an attempt to attract the attention of male dogs. She may invite the male to mount her by turning her rear towards him and holding her tail out of the way. She will fan her tail gentle to help him catch her scent.

Diestrus: The Third Week of Heat

The third week of your dog's heat cycle is known as diestrus. With diestrus, your dog's fertile period ends.

Signs of the end of your dog's fertile period include:

  • Gradual reduction of vulva swelling.
  • Cessation of flirting, whether bred or not.
  • The discharge will once again turn red, and will gradually taper off until it ceases.
  • If breeding was successful, diestrus may encompass the 63 day gestation period.

Anestrus: The Resting Period After Estrus

If breeding was not successful during the estrus period, your dog will go back into anestrus, the resting period. This period lasts between five to eleven months, and when it ends your dog will experience another heat cycle.