Dear Doctor,
Lulu has been bleeding from her private parts for more than a month. How long does a heat last? I’m cleaning up after her every 15 minutes. Someone told me she might have gonorrhea.
Distressed in Lords Bank
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Dear Distressed,
The heat cycle for a female dog averages three weeks, with bleeding lasting perhaps a week. If your dog has mated in the past and has been bleeding from her vagina for more than a week, or has a red, bulging mass coming out of the vagina (or penis for a male), then the bleeding is likely from a canine transmissible venereal tumor, a sexually transmitted disease, and will need to be examined by your veterinarian.

The physical exam will focus on your dog’s genital organs. Canine transmissible venereal tumors (TVTs) are cauliflower-like in appearance. They range in size from a small nodule of 5mm to a large mass greater than 10cm. The surface is often ulcerated and inflamed, roughed and reddened, and bleeds easily. TVTs may be solitary or multiple and are almost always located on the genitals. A tissue sample of the mass might be taken during the exam. TVTs are usually easily diagnosed by microscopic examination of the tumour cells. TVTs may be more difficult to distinguish when they occur in parts of the body outside the genitals.

TVTs are transmitted through the act of sex and can also be transmitted by oral contact. Intact, free roaming dogs are at greater risk of acquiring and spreading this disease. Your attending veterinarian will need a complete health history with as much information as possible regarding when the symptoms began, how much freedom your dog has to roam freely, or whether there are other dogs that roam the area and can get in your yard. If you have been attempting to breed your dog, you will also need the history of the stud (or bitch).

Although regression of the tumor can occur on its own, TVTs usually get progressively larger and should be treated. Chemotherapy is the treatment of choice. Vincristine sulfate is injected IV once weekly for 3 to 6 weeks. The prognosis for total remission with chemotherapy is good, unless the tumour has spread to other organs. TVTs can spread to the skin and still be responsive to chemotherapy. Sometimes the chemotherapy can make your dog feel sick and you will need to maintain good nutrition to help your dog to recover quickly without complications.

Neutering your pet will help prevent the spread of a canine transmissible tumor to your dog. Your dog will not want to roam and meet undesirables, nor will undesirable dogs come into your yard to mate. If you do want to breed your dog at some point, both dogs should be checked for TVTs before crossing.

Love your pet – see your vet.