Spay/Neuter Good For Health?…..Maybe Not

Many of our puppy buyers contact us with questions about spaying or neutering- should they do it, and if so, at what age, etc? The answers are not entirely clear, but contrary to what has been considered common knowledge for ages, spay/neuter may not be as healthy for dogs as we have all been told, especially if done at the early ages so often recommended.

Spay/neuter is almost always presented as an entirely beneficial procedure with no adverse consequences. This is simply not true. Here are some references on the subject that we recommend to anyone considering a spay/neuter.

Long-Term Health Risks and Benefits Associated with Spay/Neuter in Dogs
Canine ovariohysterectomy and orchiectomy increases the prevalence of ACL injury
Spay, Neuter, and Cancer: Revisiting an Old Trinity

Summary of the Benefits and Risks.

Males

Benefits:

• Eliminates the risk of testicular cancer (fatalities are rare, almost always cured with surgery)
• Reduces the risk of non-cancerous prostate problems (common)
• Reduces the risk of parianal fistulas

Risks:

• Significantly increases the risk of osteosarcoma, especially if done before the age of one year (common cancer in some medium/large breeds, almost always fatal)
• Increases the risk of hemangiosarcoma (fairly common in older setters, always fatal)
• Triples the risk of hypothyroidism (English Setters have the highest rate of all breeds)
• Increases the risk of geriatric cognitive impairment
• Triples the risk of obesity, which is associated with an increased risk of ruptured cruciate ligament, hypothyroidism, diabetes, pancreatitis, cancer, etc.
• Quadruples the risk of prostate cancer (uncommon)
• Doubles the risk of urinary tract cancer (uncommon)
• Increases the risk of orthopedic problems
• Increases the risk of adverse reactions to vaccinations

Females

Benefits:

• If done before 2.5 years of age, greatly reduces the risk of mammary tumors (very common, can be fatal)
• Eliminates the risk of pyometra if the surgery is done properly (fairly common in older females, can be fatal)
• Reduces the risk of parianal fistulas
• Eliminates the risk of uterine, cervical, and ovarian cancers (rare)
• Eliminates the risks to the female from being pregnant/whelping

Risks:

• Significantly increases the risk of osteosarcoma, especially if done before the age of one year (common in some medium/large breeds, almost always fatal)
• More than doubles the risk of hemangiosarcoma (fairly common in older setters, always fatal)
• Triples the risk of hypothyroidism (English Setter has the highest rate of all breeds)
• Doubles the risk of obesity, which is associated with an increased risk of ruptured cruciate ligament, hypothyroidism, diabetes, pancreatitis, cancer, etc.
• Causes urinary incontinence in up to 20% of females
• Increases the risk of recurring/chronic urinary tract infections, and several other genitourinary disorders
• Doubles the risk of urinary tract tumors (uncommon)
• Increases the risk of orthopedic problems
• Increases the risk of adverse reactions to vaccinations

Complications from the surgery and anesthesia should also be considered. Studies show a rate of around 20%, with up to 4 % of females having serious complications. Serious complications are less common in males, but do occur.

For males it’s fairly obvious that it’s better from a health perspective to leave them intact. Prostate problems and testicular cancer, both of which are most likely to occur in old age, can be dealt with by neutering when/if they do develop.

Because mammary tumors are so common, the choice for females is less clear. Mammary cancer can often be cured with surgery, but not reliably, so the risk needs to be taken seriously. The chance of developing tumors increases with each of the first few heat cycles, and the best prevention is a spay before any heats occur. Taking into account all of the potential benefits and risks, if you choose to spay it is probably better to wait until after females are physically mature. Please read the first reference above, which compares the relative risks for mammary tumors when the spay is done at various ages and heat stages before making this decision. Whether the benefits from spaying outweigh the associated risks is a judgement call, and one we are glad we don’t have to make with our own dogs.

Other Considerations

Early spay/neuter will cause a dog to grow longer and taller than it would if left intact until physical maturity.

Spayed/neutered dogs usually will develop a longer, finer, fluffier coat that looks wispy and feels cottony. This coat change seems somehow to be almost unknown in the veterinary community, but we have seen it to at least some degree, sometimes extreme, in all of the dogs we and others have spayed or neutered.

Intact females can be difficult to manage for many owners. Their heats are messy, can occur at inconvenient times (like during a long-planned hunting trip) and the dog must be carefully supervised 100% of the time to avoid an accidental breeding.

Intact males may wander if there is a female in heat within scenting distance. In our opinion this is not a good argument for neutering. Left to their own devices most hunting dogs will end up wandering some if allowed to be outside unsupervised. No dog, intact or not, should ever be outside on its own unless securely fenced. To do otherwise is neglecting their safety.

Probably the main motivation to encourage universal spay/neuter has been an attempt to lower the number of unwanted litters and abandoned puppies (or in the case of some organizations to eliminate pet breeding altogether). Among our puppy buyers there have been a few accidental litters caused by lapses in judgement on the part of the owners, a classic example being one person who thought his dogs wouldn’t breed if he was feeding them steaks. Given the number of animals that end up in the pound or turned over to rescue groups there is a very good argument for spaying females. However, the blanket recommendation to spay/neuter based on health considerations is not supported by the available research.