At 4 months old, the perfect little freckled-face bundle of joy has suddenly become a weapon of mass destruction. Your shoes look like they have been through a blender. Your beautifully manicured backyard has been turned into a wasteland of uprooted shrubs and potholes large enough to lose a small child. Desperate to find a solution to the carnage, you begin to mull over ways to funnel all that endless high-octane energy. Road working puppies is never an option but there are other ways to work off some of that energy and produce a great companion as well. Perhaps agility? Maybe the field? All are great options for those of us who like the challenge of molding all that raw energy into a top performing athlete. So now that you have decided on a plan, have you thought about when you are planning to spay or neuter? If a performance dog is in your future, recent research studies have suggested that veterinarians should reevaluate the standard protocol in which all dogs that are not intended for breeding should be spayed or neutered at or before 6 months of age.

From birth through the growth phase, bone growth provides the basic mechanical function to: 1) provide the surface area for joints, 2) provide attachment for muscles, 3) maximize bone strength against compression, shearing and bending forces during physical activity. Growth in length of long bones is more complicated with the diaphysis (bone shaft) and flared ends of the bones growing simultaneously, with length growth predominating. At the same time removal of bone is taking place on the internal surface of the bone to minimize weight and provide enough space for hemopoietic (blood forming) and fatty marrow. Sex hormones play an important role in closure (ossification) of growth plates during puberty which halts further long bone development. However there is significant documented research evidence that suggests that dogs and bitches that have been spayed or neutered before puberty will continue to grow, frequently with substantial changes in body proportions. In the Journal of Veterinary Medicine (2004) it was reported that Golden Retrievers that were spayed/neutered less than one year of age were significantly taller than those neutered at more than one year. Those dogs most often not only exhibited longer limbs but also lighter bone structure and more narrow chests. This excessive growth was linked to several other health related issues. For example, as a result of the limbs becoming longer, they also became more susceptible to fractures since they had not achieved peak bone density. According to Zink (2005) this type of disproportional growth can put excessive stress on the cranial cruciate ligament (CCL) causing it to rupture. Also there is evidence to suggest there is a relationship between the development of canine hip dysplasia and dogs that were spayed/neutered before 5 ½ months of age (JAVMA 2004).

In addition stress related damage to bone in spayed/neutered dogs, there appears to be a 5 times greater risk of hemangiosarcoma in spayed bitches and a 2.4 times greater risk in neutered males as compared to intact males (J Vet Intern Med 1999). Also in two different studies, with one study using 3214 dogs, it was determined that neutered dogs had a two-fold higher chance of developing bone cancer (Cancer Epidemiol Biomarkers Prev 2002; Vet J 1998).

Canine athletes require a different level of physical strength and endurance than is expected from the typical English setter couch potato. Most English setter breeders are very aware of how quickly their particular bloodlines mature. While some lines may mature at 12 months, others may take two years or more. If you are fortunate enough to own one of these unique individuals, delaying spay/neutering until the dog has reached puberty (typically after 1 year of age) should be considered as an option to ensure healthy bone development.

By Dr. Michelle Raisor, Ph.d