Today’s question: what do we know about the health of English Shepherds, and what can we do to protect it?

The health of purebred dogs in general is a hot topic; unfortunately, many of the headlines are negative. A Google search on “health purebred dogs” pulls up articles expressing concern over genetic disease, cancer, shortened lifespans, and crippling deformities in some popular dog breeds. Do these concerns apply to English Shepherds? And if so, to what extent?

The short answer is… we need more information! There isn’t any systematic surveillance for health problems in English Shepherds. We know that markers for some specific genetic diseases are found in the breed; and, we know that some English Shepherds are affected by complex disorders such as hip dysplasia, epilepsy, autoimmune problems, and cancer. We do not know how widespread or severe these problems are, however. That being the case, we can simply note that English Shepherds are at risk for health problems common to many breeds (and mixed breed dogs), screen accordingly, and take some common sense actions to protect the health of the breed.

Population Health

Previous blog posts have reviewed data on population-wide issues related to genetic diversity in English Shepherds. The breed’s relatively low but increasing average coefficient of inbreeding (COI), available but under-used genetic diversity, and small effective population size are all issues where action now can protect future generations. Please check out those posts and think about how your choices, as a breeder, are shaping the future of the breed!

Specific recommendations for breeders include:

  • Track the level of inbreeding (COI) in your dogs; avoid increasing average COI over time.
  • Extend generation time to 4 years or above; in particular, use older stud dogs.
  • Maintain a range of sire and dam lines in the breed (collective action required!).
  • Balance the number of sires and dams used (avoid popular sires).
  • Aim for sibling contribution (more representatives per generation).

For more information on these issues, see our 2019 Breed Report.

Medical Tests

In addition to preserving genetic diversity, which specific health/ disease tests should breeders be doing? How should the results of these health tests be used? These are big questions but we will try to summarize what’s known and offer some practical suggestions.

First, recommended health screening tests for all English Shepherds:

  • Physical exam by veterinarian
  • Hip x-ray (PennHIP or OFA)
  • Eye exam (CAER)
  • Genetic screening (eg, Embark)

Second, share results of health screening by submitting reports to a public database (eg, OFA) and notifying your dog’s breeder.  Gathering information but then not sharing those results limits the value of health testing.  English Shepherd breeders are all working within the same gene pool;  managing health within the breed is most effective when breeders share information and work together.

Finally, use results to screen prospective breeding dogs and select appropriate mates.  This may sound obvious but this is actually the step of the process that is the most complex.  There is a temptation to categorize information in black and white terms — to assume that either a dog “passes” or “fails” each test, and a “failed test” means a dog is unsuitable for breeding.  In fact, most of the information breeders gather falls on a spectrum, and there are many variables that need to be balanced in any breeding decision.  Each piece of information collected, from hip score to genetic tests to working profiles to general size, build, temperament, helps fill in the picture; taking all of it together will produce the best decision.  No dog is “best” in all categories.  Many dogs have valuable traits, and can contribute to the breed, while also having some areas that can be improved by selecting the right mate.

Test Recommendations

Physical Exam

A routine physical exam by your veterinarian will assess your dog’s body condition and screen for common medical problems such as dental issues, allergies/ skin problems, metabolic problems such as kidney disease, and heart disease.  At a minimum, breeding stock should undergo regular screening to assure good overall health and structural soundness.  If problems are noted on exam, early intervention can limit their impact on health and quality of life.  Dogs that are used for breeding should be capable of living comfortable, active lives, without special accommodations needed (medication, special diets, etc).  This basic level of health is what a general exam can document.

Hip Screening

Hip x-rays are necessary to screen for hip dysplasia.  For information on OFA and PennHIP testing, see this webpage.  Data collected by the Orthopedic Foundation for Animals over the past 30+ years documents that hip dysplasia is present in some English Shepherds, as noted on the table below.  Given the complex inheritance of hip dysplasia, ongoing testing – at each generation – is needed to minimize risk.  Breeders can not assume that their dogs have normal hips because their dog’s parents’ hips were normal – selection for healthy structure needs to be maintained for every breeding.


A second hip screening method, the “PennHIP” exam, is available and offers some advantages over a simple hip x-ray (OFA type).  PennHIP measures the amount of laxity/ looseness present in the hip joint and calculates a “distraction index” for each hip.  The amount of laxity present is associated with risk for arthritis — higher laxity, higher risk.  Data compiled over the past several decades shows that, as a breed, English Shepherds typically have a moderate amount of laxity in their hips (DI between 0.3 and 0.7).

The data on the chart below shows the distribution of “DI” scores in English Shepherds and related herding breeds based on all dogs tested from 1993 – 2020.  Note that 75% of English Shepherds have DI > 0.35. The distribution of DI across these breeds is virtually identical and mirrors the distribution seen in all dogs (pooling results across all dogs/all breeds).  That being the case, it appears that some risk for hip dysplasia is present in a majority of dogs – and selection for lower risk (lower DI), while a worthwhile goal, is not a one-generation process.  It will take many years and multiple generations to shift the entire population towards tighter hips; attempting to accomplish that too quickly, by applying very stringent thresholds to selection (eg, DI < 0.3), would result in a genetic bottleneck and ultimately do more harm than good for the breed as a whole.  At this time, selection for hips with DI < 0.7 is recommended.  Dogs with looser hips should be paired with dogs with tighter hips, in general.

For more information on hip screening, check out the Functional Breeding Collaborative podcasts, hip dysplasia – part 1 and hip dysplasia – part 2

Eye Exams

An eye exam by an ophthalmologist is necessary to screen for “progressive retinal atrophy” (PRA), a genetic disorder that eventually results in blindness as dogs age.  There are several different genetic mutations that can cause PRA.  Recently, several English Shepherds have been diagnosed with a form of PRA for which there currently is NO genetic screening test — the only way to identify affected dogs is by ophthalmology exam.  The dogs affected by this form of PRA test clear for the known PRA mutations (eg, PRA-prcd).  The English Shepherd Breed Conservancy is assisting with data collection for a study by the University of Cambridge which aims to identify this new PRA variant.  When the specific mutation is identified, it will be possible to identify carriers and avoid breedings that put puppies at risk.  You can help with this research by (1) testing your dog, and (2) sharing the eye exam report for any dog over 7 years old when tested with English Shepherd Breed Conservancy.  To find a low cost eye screening clinic, check out the list on the Cavalier Health website.

Genetic Testing

DNA testing, using a panel such as the one offered by Embark,  allows identification of dogs that carry one or two copies of specific gene mutations associated with disease.  In most cases, these mutations act in a “recessive” manner;  dogs that have one copy of the mutation do not manifest a problem.  Knowing which particular mutations a dog carries allows breeders to select mates for their dog that are clear for that mutation, and so avoid producing puppies that are affected by that genetic disorder.

The table below shows the frequency of genetic variants identified in English Shepherds in 2023 (sample size > 1000 dogs).  The rows on the chart indicate what percentage of dogs carry 0 (clear), 1, or 2 copies of the variant and the overall allele frequency in the population in 2023.  Each of these variants is inherited independently; based on the frequencies of these variants in the breed, roughly 50% of English Shepherds may carry at least one identified variant.

It is important to keep in mind that ALL dogs carry some genetic mutations.  At present, only a small percentage of diseases have genetic tests available;  the number of testable diseases increases every year, however.  What this means is that, in time, it is virtually certain that ALL dogs will test positive – as a carrier – for SOME risk-associated genes; testing positive does not mean that a dog will have a problem or that it is unsuitable for breeding.  The goal of genetic testing is NOT to eliminate all dogs found to be carriers of defective genes but rather to use test results to choose matches where both parents do not carry the SAME defective genes.  In this manner, breeders can produce healthy puppies without constricting the gene pool unnecessarily.

Summary

A healthy future for English Shepherds as a breed requires ongoing selection for attributes associated with good health.  Breeders have a variety of tools available to measure the health of their dogs.  Tests recommended for English Shepherds include measures of overall health (vet exam), hip and eye screening, and DNA testing for risk variants.  In addition, pairing dogs so that the COI for litters is low (<7%) will minimize the risk for genetic diseases for which we do not have specific DNA tests.

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