Disease Risks Associated with Spay and Neuter: A Breed-Specific, Gender Specific

This study extends the investigator’s recently completed AKC Canine Health Foundation-funded project studying 12 dog breeds to identify major differences in the degree to which spay or neuter may be related to an increase in joint disorders (hip dysplasia; cranial cruciate ligament tear) and/or cancers (lymphoma; hemangiosarcoma; and mast cell tumor).

The original breeds studied were: Labrador Retriever, Golden Retriever, German Shepherd Dog, Rottweiler, Boxer, Bulldog, Doberman Pinscher, Dachshund, Corgi (both breeds), Chihuahua, Yorkshire Terrier and Shih Tzu. Findings did not associate an increase in disease association in the small breeds with spaying or neutering, while in larger breeds disease risk was dependent upon gender, and whether the spay or neuter procedure was performed before or after one year of age (Hart, B.L., L.A. Hart, A.P. Thigpen and N. H. Willits. 2014. Long-term health effects of neutering dogs: Comparison of Labrador Retrievers and Golden Retrievers. PLoS ONE 9(7): 10.1371/journal.pone.0102241).

In this second phase, the following breeds have been added to the study: Great Dane, Australian Shepherd, Bernese Mountain Dog, Cocker Spaniel, Border Collie, Beagle, St. Bernard, Irish Wolfhound, Jack Russell Terrier, Pug, Maltese, Pomeranian, Miniature Schnauzer, Boston Terrier, Australian Cattle Dog, Shetland Sheepdog, English Springer Spaniel, Cavalier King Charles Spaniel, and West Highland White Terrier. Upon completion of the study, the major publisher, Wiley, has agreed to place the total data set of all 31 breeds on an open access website as a resource for breeders, dogs owners, researchers and veterinarians.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02275


Dr. Benjamin L Hart, DVM, PhD
University of California, Davis
Amount: $3,000 in 2016 with an additional $2,000 in 2017

Mapping of Genetic Risk Factors for Canine Hip Dysplasia

Hip dysplasia is an inherited disorder of Portuguese Water Dogs. Currently, breeders utilize phenotypic screening methods in an effort to decrease the incidence of this disease in the breed. However, understanding the genetics of this disorder would have a profound impact on the ability of breeders to prevent this disease in future generations. Breakthroughs in other breeds can be utilized to better understand the genetics of this condition in Portuguese Water dogs.

Research Objective

Canine hip dysplasia is a common developmental disorder of the hip joint that severely affects a dog’s quality of life. As the disease has several genetic risk elements and is influenced by environmental factors like diet and exercise, it is of paramount importance that genetic association studies are conducted using adequately-sized cohorts of genotyped diseased and healthy animals.

Dr. Iivanainen will sample a large population of dogs (>300-400 dogs) so that contributing genetic loci can reliably be discovered. This research group expects that with such a strongly powered study all major genetic risk factors can be uncovered with a high statistical significance. Investigators expect that identified loci will be discovered across breeds. The identification of genetic risk elements will allow the development of genetic tests that can be used in breeding programs to control the disease incidence, as well as further studies regarding the possible role of diet and exercise in hip dysplasia development.

Co-sponsored with the Morris Animal Foundation, Grant Number: 01828


Dr. Antti Iivanainen, DVM, PhD
University of Helsinki and the Folkhälsan Institute of Genetics

Mapping Refinement of Quantitative Trait Loci for Canine Hip Dysplasia

Hip dysplasia is one of the most common inherited traits in dogs with an extremely high incidence in some large breeds. It is caused by mutations in multiple genes. In previous studies, investigators discovered the genetic markers that point to the chromosomal regions that harbor the genes that contribute to hip dysplasia.

In this study, they will narrow down these regions through additional genetic evaluation. By narrowing the regions that harbor hip dysplasia genes across breeds, they hope to discover the contributing mutations and use that information to design genetic tests that can be used to prevent the propagation of dysplastic dogs.


Researchers identified the first mutation associated with canine hip dysplasia in Labrador retrievers. This mutation could be used in conjunction with a panel of genetic markers to identify susceptible dogs. The team also learned that there is no single gene identified for hip dysplasia in dogs. This study pointed to several other genes that contribute to the disease, and researchers believe they will discover these genes through the process they have developed.

Based on their findings, the researchers hypothesize that identifying dogs that are resistant to hip dysplasia will involve a panel of genetic markers that may be breed specific. Breeders could then use these panels in conjunction with breeding values to genetically screen puppies before the mutations themselves can be identified. This project lead to the discovery of the first gene associated with canine hip dysplasia.

Co-sponsored with the Morris Animal Foundation, Grant Number: D04CA-135


Rory J. Todhunter, BVSc, PhD
Cornell University