The best age to spay a female dog varies depending on the breed and size of your dog. Studies have shown a possible link in large dogs between early spay/neuter and certain joint disorders (hip dysplasia, elbow dysplasia, injuries to the cranial cruciate ligament) and cancers (lymphoma, hemangiosarcoma, osteosarcoma, and mast cell cancer). This may be because the hormones associated with growth and development come from the gonads, so leaving the ovaries in place longer enhances the dog’s musculoskeletal health.
If you have a small breed dog or a mixed-breed dog less than 42 pounds, the timing of spay has not been linked to any of these diseases. Additionally, small dogs are not prone to developing spay incontinence (hormone-associated urinary incontinence after spay), which is also mainly large breed dog problem. What all this means that if you have a small dog, you can have her spayed whenever you want. (The exception is if you have a Shih Tzu. In one study, Shih Tzhs had a significantly higher risk of cancer if spayed before 1 year of age, so you’re better off waiting until she is 2.) Most veterinarians will spay small dogs as early as 6 months of age, before they have a heat cycle.
Large Dog Spays
The general recommendation for large breed dogs is to wait until at least 12 months to spay, as many of these breeds have shown an increased incidence of joint disorders and cancers if spayed earlier. This is especially true for Golden Retrievers, Viszlas, and Rottweilers. Cancer is so prevalent in Golden Retrievers, and so much higher in spayed Golden Retrievers, that some experts suggest not spaying Golden Retrievers at all. Spaying large breed females later also reduces the risk of hormone-associated urinary incontinence.
Overall, there are more pros than cons to spaying your female dog if she is not intended for breeding. Spaying means no messy heats, no unwanted pregnancies, less chance of breast cancer, no chance of ovarian or uterine cancer, and no chance of uterine infection (pyometra), which is a very common surgical emergency in older, intact (not spayed) female dogs.
When to Spay a Dog After a Heat Cycle
Remember that dogs come into heat approximately every six months. So, if you’re planning on having your dog spayed later, schedule the surgery so it is around two to three months after a heat. This allows time for everything to quiet down inside and the blood vessels that became enlarged during heat to get smaller, making the surgery a little safer and less complicated than when she is in heat.