Early spay and neuter in dogs can have repercussions on their future health. Research shows that early spay and neuter, at least in the breeds it has been researched in, causes health problems. It can cause an increase in certain types of cancer. Early spay and neuter also causes changes in the normal conformation in dogs. Why do we spay and neuter dogs at such a young age? What does it mean if we do?
Spaying and neutering before puberty seemed to be the answer to help with the excess pet population. This prevents dogs from every reaching sexual maturity and the subsequent opportunity to make puppies. Studies at that time also showed that early spaying could also reduce the incidence of mammary tumors in dogs. Early spay and neuter did not seem to have any downside. As a result, in the 1970’s and 1980’s, early spay and neuter became the new paradigm for pet population control.
The effect of early spay and neuter on conformation is a direct result of avoiding puberty. Reaching sexual maturity is a signal to the body that it is time to quit growing. This happens because the hormones associated with puberty tell the bones to stop growing. Bone length is permanently set within a few months of reaching puberty. Early spay and neuter stops puberty and the growth plates don’t close at the appropriate time. They eventually close by other mechanisms, otherwise our dogs would never stop growing!
This means that these longer bones are disproportionate in relationship to the joints that serve them. This causes excess stress on the joints, possibly leading to osteoarthritis. More importantly, it has a huge impact on the knee joint, causing gradual deterioration of something called the cruciate ligament. This ligament plays an important role in the stability of a dog’s knee. Without it, most dogs will never walk normally again, at least not without expensive intervention with either surgery or rehabilitation.
Cases of cruciate rupture increased in the late 1980’s and early 1990’s. This happened because those early neuter and spay dogs were reaching maturity and a lifetime of body mechanics caused a gradual breakdown of the ligament. As a result, the number of surgically treated dogs skyrocketed. Surgical treatment of cruciate rupture is the single largest income source for orthopedic surgeons. Dog owners spent $1.32 BILLION dollars in 2003 for the treatment of cruciate disease. J Am Vet Med Assoc. 2005 Nov 15;227(10):1604-7.
Don’t let your dog become a statistic! Do not spay or neuter your dog until after puberty.