Should we neuter large breed dogs later? Adult size matters!
A recent study conducted by researchers at the University of California at Davis concluded that mixed-breed dogs with an higher adult weight have higher health risks if neutered or spayed early. The study published in Frontiers in Veterinary Medicine concluded that dogs weighing more than 44 pounds as adults are at higher risk for one or more joint disorders if neutered before 1 year of age. Dogs weighing up to 43 pounds had no increased risk for joint problems. Neutering male and spaying female dogs at or before 6 months of age has become routine in much of the world. However, investigations have revealed that joint disorders and some cancers may increase in association with early neutering. One study found that hip dysplasia and cranial cruciate ligament tears or ruptures were more likely in neutered than intact dogs.
Neutering is also associated with an increase in excessive tibial plateau angle and cranial cruciate ligament disorders. Certain cancers are also known to be more likely in neutered than intact dogs. The occurrence of lymphoma was found to be higher in spayed than intact females, as was the occurrence of mast cell tumors and hemangiosarcoma. A study of over 40,000 dogs utilizing the Veterinary Medical Database found that neutered males and females were more likely to die of cancer than intact dogs. Neutering appears to even have an effect on brain function. Neutering males is associated with accelerated signs of age-related cognitive dysfunction and an association between the absence of estrogen (due to spaying) and accelerated brain aging in females has also been reported.
In the UCDavis study, there was a relationship of body weight and association of neutering with increased risks of joint disorders. Dogs with an adult weight above 20 kgare significantly at risk for joint disorders when neutered at an early age. The study offers useful guidelines for ages of neutering with regard to avoiding the increased risk of painful and disabling joint disorders. The authors conclude that adult weight should be considered when planning to neuter their animal. Pet owners and veterinarians should consider this information when making decisions or recommendations regarding the age for neutering a dog that will be in a specific adult weight category.