Heat Cycles in Dogs and Cats

Heat cycles are those times of year when pets are fertile and may be bred.  In dogs heats usually occur twice a year and can last up to 3 weeks in many pets.  Symptoms include:

  • Vaginal swelling
  • Bloody discharge
  • Increased attraction of male dogs

Typically pets over 6 months of age may start their first heat cycle  It is important that during this time animal guardians not allow their female dogs off leash and/or unsupervised due to the possible presence of male dogs, as most female dog bitches will allow breeding during this time.


In cats heats can occur. Unspayed female cats typically have 2-4 heat cycles per year, but may have many cycles certain times of year such as spring or fall. Unlike dogs, cats typically don’t have vaginal swelling and/or discharge, but they become more affectionate often lifting their hind end off the ground, as well as vocalizing and rolling on the floor.

It is best to spay a female dog and /or cat to avoid unwanted pregnancies, and adding to the pet overpopulation problem already present.  I usually recommend waiting 30 days after a pet goes out of heat to have them spayed.  Due to recent evidence of increased health benefits later on in life, I recommend waiting to spay a female dog until sexual maturity at age 10-12 months.  Cats can be spayed over 6 months of age, although many shelters are doing them much younger.

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  1. I really don’t know much about heat cycles in dogs and cats. Enjoyed learning about it. Thank you


  2. Dr. Michael Dym, VMD veterinarianNovember 23, 2011 at 11:31 pm

    You are very welcome Joanie. Spread word about this service to your friends and family.

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  5. is there anything available for dogs when their in heat to relieve the discomfort or settle them down? My dog is 4 and not been spayed. I don’t know if I want to. She is a little ponche. what age do they slow down from the heat stages?

  6. Dr. Michael Dym, VMD veterinarianJune 14, 2013 at 11:06 am

    Heat cycles can last throughout much of life of pet. Try natural calming agent Be serene from 1800petmeds to see if can help calm her during heat. Also consider spaying her when out of heat.

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