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Coventry Animal Hospital Discuss Dogs in Their Heat Cycle

By March 7, 2014 September 5th, 2014 Small Animal


Some small breed dogs may start their cycle as early as four months of age, whereas giant breed dogs may not have their first heat cycle until 18 to 24 months.  A female dog that is not spayed is known as the “bitch”.  Your female pet can become pregnant on their first heat cycle, as they are sexually mature.  This is inadvisable, as they are not done growing and are more likely to have complications associated with the birthing and be poor mothers.  At Coventry Animal Hospital, we recommend spaying (ovariohysterectomy) your pet at six months of age.

Dogs generally have one heat cycle every six months.  The cycle starts with the proestrus phase for approximately nine days: the bitch will develop a swollen vulva and have bloody vaginal discharge.  The male dog will show interest in them, but the female will not yet be receptive.  This is followed by the estrus phase, which lasts for approximately 10 days.  During this phase, the vaginal discharge becomes straw-coloured and the female may accept a breeding male.  The female then goes into either the diestrus phase or pregnancy for approximately 63 days.  If she is bred, but does not conceive, she may develop a “false pregnancy”, where her body has pregnancy hormones, but no puppies.  Unlike human women, when female dogs get older, they do not stop cycling.

It is recommended to spay a female pet before their first heat to eliminate their risk of accidental pregnancy and minimize their risk of reproductive diseases.  Please refer to our website for Pet Health Articles under ‘Spay’.  A female pet that is not spayed is at risk for life-threatening pyometra (an infection in their uterus), as well as breast cancer.

Accidental pregnancy can easily happen as separation within a household can be extremely difficult.  If the male and female are together for a 10 minute time-frame, that is long enough for them to breed.  Brothers and sisters will mate once they become sexually mature – they do not know that they are related.  Pets living on the farm will be more likely to roam off their property in search of a mate.

Here at Coventry Animal Hospital we encourage having pets spayed when they are not in heat.  Pets can be spayed while in heat, but there is a higher risk of bleeding during surgery, as their reproductive organs have increased blood flow.  It is more expensive to spay a pet that is in heat, pregnant, obese, or older than one year of age, as these are all factors that make the surgery more difficult.

If you have any questions about spaying your dog, then don’t hesitate to contact Coventry Animal Hospital.  We would love to discuss it with you!