Health Testing and the Decisions Behind a Breeding
Health testing is one of the most important tools I have when I'm planning a breeding. It's also one of the easiest parts of breeding to turn into a checklist.
Did they do hips? Check. Elbows? Check. Eyes? DNA? Does the dog have a CHIC number?
Those are good questions to ask. I just don't think they're where the conversation should end.
I want health testing to give me useful information about the dogs I'm breeding. Then I need to understand what those results mean, what I know about the dogs and families behind them and what risks I'm comfortable with in a particular pairing.
Breeding is both art and science. Health testing is an important part of the science, but the results don't make the decisions for me.
Labrador Health Testing: Where I Start
Every breed has its own health concerns, and the testing I do starts with those known concerns in Labradors. Hips and elbows are evaluated radiographically for dysplasia. Eyes are examined regularly by a board-certified veterinary ophthalmologist. Cardiac screening is available at different levels. Then there is DNA testing for inherited conditions and traits found in the breed.
My own DNA panel is considerably more extensive than the small number of DNA tests included in the Labrador Retriever Club's current CHIC requirements and recommendations. That doesn't mean I test for every variant a laboratory is capable of reporting. There are genetic conditions that aren't considered a concern in Labradors, and I don't see much value in collecting results just to make the list of tests look longer.
Cardiac screening is one area where I've chosen to go beyond the minimum recommendations for dogs in my own program. My breeding dogs that live here receive echocardiograms. I value the additional information an echo can provide, so that's a standard I've set for my dogs. I don't turn that into a universal line in the sand for everyone else.
For years, annual cardiac clearance by a board-certified veterinary cardiologist, using auscultation to listen for a murmur, was a standard approach for breeding dogs. It's still an accepted form of cardiac screening today. The Labrador Retriever Club currently recommends cardiac screening but does not require it for CHIC.
What Health Testing Can and Can't Promise
I can do extensive health testing on two dogs and still can't promise that every puppy they produce will go through life without a medical problem…that's biology. Two healthy human parents aren't guaranteed a child who will never develop a medical condition either. We understand that intuitively with people, but sometimes expect dog breeding to offer guarantees that genetics simply can't provide.
There are conditions we don't have tests for. Some diseases have complex inheritance. Some are influenced by multiple genes or environmental factors. Sometimes something appears in a pedigree that hasn't appeared before. None of that is an argument for doing less testing. It's a reason to be realistic about what health testing can accomplish.
Health testing gives me more information. It helps me identify and reduce risks I might otherwise never see. Over generations, it can help breeders make better decisions for their dogs and for the breed. It can't eliminate every health risk from a litter.
OFA, CHIC and the Results Behind the Acronym
OFA is one of the resources I use when I'm researching dogs, their relatives and potential breeding combinations. When results are recorded there, having health information collected in one searchable place makes it much easier to research a pedigree.
CHIC (the Canine Health Information Center) is a part of OFA. For any given breed, the parent club determines which screenings are required for a dog to qualify for a CHIC number. Once those requirements have been completed, recorded with OFA and made public, the dog receives a CHIC number.
A CHIC number does not mean the dog passed every test.
A Labrador with a failed hip or elbow evaluation can have a CHIC number. A Labrador that carries dilute—or is dilute—can have a CHIC number. CHIC tells you that the required screenings were completed and the results were made available. You still need to look at what those results actually were. That's why I'm cautious about giving the presence of a CHIC number too much weight when I'm evaluating a breeder.
Some health results originate with OFA. Hip and elbow radiographs, for example, are submitted there for evaluation. Other testing is performed elsewhere. A DNA laboratory gives the breeder genetic test results. Eye and cardiac examinations are performed by the appropriate veterinary specialists. Those results don't become more or less favorable based on whether every one of them ultimately appears in the OFA database. Some breeders choose to submit outside results so their dog's health information is collected in one place and the dog can qualify for CHIC. Others have the testing and original documentation but don't submit every eligible result to OFA.
For a puppy buyer, I think the more useful questions are whether the appropriate testing was completed and what the results were. OFA can make much of that very easy to verify. If a result isn't recorded there, the breeder should still be able to provide the documentation.
OFA and CHIC are helpful resources. Use them. Look up the dog. Look at the individual results and, when possible, the relatives too. A CHIC number is useful information, but it isn't a shortcut for evaluating an entire breeding program at a glance.
DNA Results Need Interpretation
Some DNA results are relatively straightforward. With a simple autosomal recessive condition, a dog needs to inherit the disease-causing variant from both parents to be genetically affected. A dog that inherits one copy is a carrier. If I breed a carrier to a clear dog, I can produce carriers, but I won't produce puppies genetically affected by that condition.
A carrier isn't a sick dog, and carrier status alone doesn't make an otherwise valuable dog unsuitable for breeding. If breeders removed every carrier of every testable recessive condition from the gene pool, we could lose perfectly good genetics while trying to eliminate a problem we already have the tools to avoid producing.
Not every DNA test gives us such a tidy answer. Canine genetic testing continues to evolve. New tests become available, new variants are identified and sometimes the science is still developing around how strongly a particular marker is associated with clinical disease. There may be other genes involved. A variant may change risk rather than act as a simple on/off switch. Dogs with the same genetic result don't necessarily all develop disease in the same way. A laboratory report might still categorize a result as clear, carrier or affected.
Before I decide what that means for a breeding, I want to understand the disease.
How is it inherited?
What exactly has the test identified?
How closely does the genetic result predict clinical disease?
Are there other known factors involved?
That's very different from looking for the greatest possible number of “clear” results on a DNA panel.
Breeding with Preliminary Orthopedic Clearances
OFA final hip and elbow clearances are issued at 24 months or older. Breeders can also choose to have preliminary evaluations performed while a dog is younger.
Prelims are great additional information. They can tell me quite a bit about a young dog's orthopedic status before it’s old enough for final clearances, and they can influence whether I continue investing in a dog as a potential breeding prospect. I still repeat the radiographs for final clearances once the dog is old enough.
My normal practice is to have finals before breeding. I also don't think an occasional breeding of a dog with good preliminary evaluations before 24 months is enough information, by itself, for me to make a sweeping judgment about someone else's breeding program. I'd want some context. There's a difference between an exception made with with good preliminary results and known orthopedic history behind him/her, and routinely breeding young dogs before they're eligible for final clearances. Those aren't particularly useful situations to lump together.
Final clearances remain the standard I expect. Prelims give us additional information before we can get there.
Putting the Results in Context
This is where breeding stops fitting neatly into a checklist. I know the individual in front of me. I know as much as I can learn about her parents, siblings and other relatives. I know what has shown up in the family. If I've already bred within that line, I have information from the dogs I've produced too.
Then there's the dog I'm considering breeding her to and all of the same information behind him.
A health result that I'm comfortable working with in one pairing may be a risk I don't want to stack in another. A carrier can be bred to a clear dog. A perfectly normal result on one individual may deserve a closer look if I know there's a pattern elsewhere in the family. Sometimes new information changes how I think about a line I've known for years.
That's why I don't think every thoughtful breeder will always make exactly the same decision from the same piece of information. We have different dogs. We know different things about the families behind them. We may have different information available to us, and we may draw our lines in somewhat different places.
There are certainly health results that can take a dog out of consideration for breeding. Nuance doesn't mean everything is acceptable if you can come up with a good enough explanation. It means I want to understand the actual risk before I decide what I'm going to do about it.
I want as much useful information as I can reasonably have when I'm planning a breeding. Health testing is a big part of that. So is knowing the dogs behind my dogs, paying attention to what we've produced, keeping up as our understanding of canine health changes and being willing to change course when new information gives me a reason to.
I don't run health tests so I can collect enough green checkmarks to breed a dog.
I run them because I want the information.
Then I have to decide what to do with it.