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

Landmark Clinical Trial to Establish the Evidence-Based Use of Regenerative Medicine to Treat Tendon Injury in Dogs

This landmark study is being performed by the Veterinary Orthopedic and Sports Medicine (VOSM) Group in Annapolis Junction, MD, whose practioners were instrumental in the formation of the newly recognized veterinary specialty of veterinary sports medicine and rehabilitation. As an active, versatile breed, sports related injuries affect a large number of PWD athletes. This study is important to better understand cutting edge areas of treatment such as the use of stem cell therapies and its application as well as safety in the treatment of orthopedic injuries.

Research Objective

Regenerative medicine is a rapidly developing field with the potential to transform the treatment of canine disease. The ability to repair damaged tissue and treat diseases once believed to be incurable may soon be a reality. However, there are concerns that some techniques are being used prematurely. Due to the lower regulatory barriers in veterinary medicine, company-sponsored regenerative medicine products and techniques are currently used in general practice and specialty hospitals without the benefit of having been preceded by stringently controlled, independently funded clinical trials. As a result, techniques vary widely and the evidence that they work is anecdotal at best.

The AKC Canine Health Foundation has made the evidence-based practice of regenerative medicine a major focus within our research portfolio. Through an ongoing commitment to fund research studies that will inform the veterinary community in the use of safe and effective regenerative medicine techniques, we intend to protect dog owners and support veterinarians with innovative technology that will consistently improve outcomes for dogs.

In support of our effort to provide evidence-based regenerative medicine research, CHF is funding this landmark study to evaluate the effectiveness of Platelet-Rich Plasma (PRP) and stem cells in the treatment of the most common sporting injury in dogs: supraspinatus tendonopathy (similar to the rotator cuff injury in humans). Tendon injuries in dogs often progress undiagnosed and result in chronic lameness and pain. Ultimately, unassisted tendon healing results in scar formation and reduced function of the joint and surrounding muscle tissue. PRP and stem cell therapies aim to accelerate and promote healing through tissue regeneration and reduced scarring.

Dr. Jennifer Barrett, MS, PhD, DVM, DACVS, DACVSMR, and Dr. Sherman Canapp, DVM, MS, CCRT, DACVS, DACVSMR, propose to conduct the first randomized, placebo-controlled clinical trial evaluating the effectiveness of PRP, adipose-derived, cultured stem cells (ASC) and commonly used stromal vascular fraction (SVF) cells. This will be the first study to directly compare efficacy of intratendinous injection of ASC versus SVF, both of which are currently commercially available despite having limited scientific evidence of efficacy.

The study will be conducted at the Veterinary Orthopedic and Sports Medicine (VOSM) Group in Annapolis Junction, MD in order to recruit real-world cases in a clinically relevant, state of the art canine sports medicine environment. Using the gold-standard ‘Blinded, Placebo Controlled’ clinical trial design, Drs. Barrett and Canapp will not only identify an effective treatment for supraspinatus tendon injury, but their research will have a profound impact on the treatment of a wide array of musculoskeletal conditions affecting dogs and humans.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 2107


Dr. Jennifer G. Barrett, DVM, PhD
Virginia-Maryland Regional College of Veterinary Medicine

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

Genotypic and Phenotypic Dissection of Canine Hip Dysplasia

A pedigree based on greyhounds and dysplastic Labrador Retrievers will be expanded to find genetic markers associated with the genetic mutations that cause hip dysplasia (HD). Several measures of the inherited traits of the dysplastic hip, age, distraction index, dorsolateral subluxation score and Orthopedic Foundation for Animals hip score, will be used to maximize the chance of finding genetic markers. The heritability, mode of inheritance, and predictability of these measures for HD will be determined.


In the experimental cross breed and Labrador Retriever pedigrees we studied, the dorsolateral subluxation score serves as the most accurate single predictor of subsequent hip arthritis but when combined with the Norberg angle, an improved estimate is obtained. Hip dysplasia is caused by mutations in multiple genes (maybe as many as a dozen chromosomes contribute to the appearance of the hip on a radiograph). These hip dysplasia genes act in both an additive manner, in which the cumulative effect of all the genes underlies the radiographic appearance of the hip. Some genetic loci improve hip quality and some are detrimental. In addition, there are also dominant loci. Now we will narrow the chromosomal regions that contain these genes so as to be in position to assess candidate genes that may harbor the mutations that contribute to hip quality. To do this, we are acquiring DNA samples and hip radiographs on as many pure breed dogs as we can. By discovery of the contributing mutations, the design of genetic tests is now possible that will enable us to screen for dogs both susceptible and resistant to hip dysplasia. This information will further allow us to follow hip development more closely in susceptible pups and introduce strategies to prevent secondary hip arthritis and to develop new treatments.

Co-sponsored with the Morris Animal Foundation, Grant Number: D99CA-001


Rory J. Todhunter, BVSc, PhD
Cornell University