Twice in the past half-year we’ve been treated to research that challenges the last few decades’ conventional wisdom on the subject of spaying and neutering dogs. This time it’s all about knees and hips—and it’s a good study.

Sure, this JAVMA study (from last week's edition, not yet online) has its population bias issues and leaves open the question on ideal timing for sterilization (crucial, IMO), but it also boasts an enormous sample size few can find fault with.

Employing a database that synthesizes data from US veterinary teaching hospitals (in this case, from 1964 to 2003), the histories of 1,243,681 dogs were analyzed to determine risk factors for cruciate ligament deficiency and hip dysplasia.

The results?

“Castrated males were significantly more likely than other dogs to have hip dysplasia, and castrated male and spayed female dogs were significantly more likely to have cranial cruciate ligament deficiency.”

Age and size were also considered:

Dogs over four were more likely to be diagnosed with cranial cruciate issues and those younger than four with hip dysplasia. Large and giant breed dogs were more at risk for both orthopedic conditions. In case you’re wondering, Newfies were voted most likely to win first prize for high frequency of hip and knee disasters.

This is a BIG study with major implications and that means big things for how veterinarians might approach the subject of spays and neuters in practice. As I’ve predicted here before, decade’s end will likely see a change in how we vets spay and neuter pets.

Vasectomy or tubal ligation, anyone?