The Ins and Outs of Pedigree Analysis, Genetic Diversity and Genetic Disease Control presented by Dr. Jerold Bell.
By Patt Caldwell
Published in the 2024 Spring issue of the Collie Club of America Bulletin.
First recorded in 2022, this presentation is one that, if not previously viewed, is of utmost importance to any level of involvement in Collie stewardship. If you have watched it before or were fortunate enough to attend the live presentation, take another look and direct your steps toward breeding healthier Collies.
When first reading the title of the 2022 CCA Breed Education seminar, you would think the presentation was riddled with a tedium of technical terminology and concepts difficult to grasp and retain. Nothing could have been further from the truth. The speaker, Dr. Jerold Bell, Adjunct Professor of Genetics, Department of Clinical Science at the Cummings School of Veterinary Medicine – Tufts University, Chairman of the Heredity Diseases Committee World Small Animal Veterinary Association, Director of OFA-CHIC, and a practicing veterinarian at Freshwater Veterinary Hospital in Enfield, CT, was engaging, warm, and passionate not only about the health of dogs, but also respectful of breed type. So engaging was he that the seminar “went over” and Dr. Bell graciously remained behind to answer questions.
The three hour plus run-over time event was divided into two parts; the first contained general information with specifics to our breed. The second dealt with Collie specific health. There really was a third part if you consider the beautiful bound handout booklet put together by Krissy Marshall. The booklet contains the usual bios of the speaker and the CCA Breed Education committee. It also contained five articles written by Dr. Bell: “Genetic Diversity,” “Understanding Breeds as Populations,” “Pedigree Analysis and How Breeding Decisions Affect Genes,” “The Effect of Genetic Testing: Constructive or Destructive?” and “Breeding Strategies for Managing Genetic Traits.” Each article has its corresponding list of references, and each is as easily followed as was Dr. Bell’s presentation. While the topic might suggest a stuffy collegial lecture, the speaker’s approach was a true presentation, engaging the audience with his topic. Dr. Bell and his wife, Candice, breed pure bred dogs, Gordon Setters, and have won at Westminster. He just doesn’t just care for dogs as a livelihood; he is personally invested with them as valued family members as well as being a preservationist breeder.
A benefit to all who hear Dr. Bell is that he personally tailors each of his presentations to the specific breed at hand. Currently he has spoken at about 80 breed club health seminars. While the morning talk contained some very general breeding information, Dr. Bell also directed much of it to our Collies. His statistics throughout were very interesting. Registration stats in 1985, when we were ranked 19th in popularity during the “Lassie bump,” were 20,000 compared to our rank of 38 in 2021 with 2,288. Litters registered in 1985 were 6,099 compared to 2021 with 1,134. Should we be concerned with a smaller number of gene choices/diversity with this significant decrease? No, he assured us, there is still enough variety to give us choices. That was comforting!
Something vets and breeders have been hearing and talking about for several years is that the average size of puppies per litter is decreasing. It was good to hear that the statistics do not prove that. The average number of Collie puppies per litter in 2010 was 5.5. The average number from 2013-2016 was 5.4 puppies per litter. From 2010 – 2021 the average number was 5.8. I know personally of a couple recent litters where 8, 10, and 12 puppies were produced.
These are my thoughts. We all personally know of litters of one and two. If smaller litters are being produced occasionally, it could have just been poor timing. If it happens often with a certain dog OR bitch perhaps we need to ask some of these questions: Was the dog’s sperm tested and not just for number? A true semen evaluation should include all of the following not just a number count: assessment of the male’s libido, a semen volume and motility, assessment of both total and progressive movement, sperm count and a stained morphology assessment of how normal the individual sperm cells look. Great libido producing a quantity of split or crooked tails, split heads, and circle swimmers will not penetrate an egg. Was the timing right? Is the male or female in a recovery stage from illness or stress? Has the bitch had a reproductive health check? There certainly are other questions to ask and other conditions to consider but it was comforting to hear that we are actually at the average.
What about the number of Collies that get bred compared to those that are registered? Dr. Bell stated that twelve percent of all Collies that are registered get bred. While this sounded like a good statistic, we still need to keep vigilant with puppy mills and those who will breed Collies without mindfulness to the breed Standard and/or Collies’ health. Breeders need to ensure that healthy, well-bred Collies are being bred and registered.
Another fact dispelled by Dr. Bell is one that breeders of any purebred dog is often faced with – the “fact” that mixed breeds are healthier than purebred dogs. Dr. Bell said, “There is as much genetic disease in mixed breeds as there is in pure breeds.” The number one disease in all dogs is allergies. There is as much hip dysplasia in mixed breeds as in pure breeds. He cited that he sees as much of these maladies in the mixed breeds as in the purebreds in his own private practice. This brought to my mind a comment my own vet made over thirty years ago when we had a young male drop significantly in semen quality. Questioning Dr. Mallow about the possibility of it being breed specific, he remarked many other breeds in his practice were suffering from the same issue at this particular time. He spent hours on the phone with vets across the country who were seeing the same thing. Dr. Mallow’s comment, in all his years of practice, he has seen these “tides” and cautioned me not to be drawn in by the “mutt-vs purebred” chatter. “We can’t really determine how many mutts are impotent because no one really checks for it.”
Dr. Bell stated what we all know, all breeds have specific genetic diseases, but they may be of low incidence, 5-10%. “Collies do have some high frequency genes, so you are in a particular situation where you’ve got some work to do. BUT, you have tests and ways to work and try to mitigate and work in that direction.”
Mitigate: lessen, abate, alleviate, decrease, allay…See where this is going?
He continued. “All individuals carry some deleterious mutations so all individuals that propagate will propagate their deleterious mutations. You always need to actively monitor and select against the genetic disease. Use your health tests AND those results in your selection.” “Health is not a consequence of breeding. Without this selection, the genetic health of the BREED will decline.” I love those two statements. Read them again. He explained what we all know. You cannot just breed and expect to get and keep health. You need to ACTIVELY work on it. It is the same with quality. “You can’t just breed and get quality; you need to work on it.” He went on, “Homozygosity or heterozygosity does not tell you anything about the health of dogs. You need to select for health genes. The italics are placed to draw your attention.
“When breeds have issues with genetic disease, the only way to improve the gene pool is through genetic screening and the selection against specific disease and their associated liability genes.” He suggests pre-screening should become the universal before our dogs are bred. This will give you more data and information you will need to make decisions. Don’t just look at the genetics. Look at everything: allergies, skin. heart, seizures… “Breed with eyes open.”
Dr. Bell presented many of the diseases/conditions that afflict Collies. When he was sharing 2006 statistics, the issue of seizures was brought up. There were percentages under two listings for this condition: seizures 5.1% and epilepsy 1.6%. He pointed out that if this were other breeds it would be said that 6.7% have epilepsy. You cannot do that with Collies because of seizures caused by drug interaction due to MDR1. Let’s continue with MDR1.
MDR1 is the abnormal ability to properly handle medications. Neurological signs caused by affliction with this condition include tremors, seizures, coma, and death. This can occur with two copies OR one copy of the gene. The mutation was discovered in 2001 and the test indicating its presence was discovered in the USA in 2004. Yay us, right? Not so much.
“In over 20 years since MDR1 was identified, the breed WORLDWIDE has not altered the frequency of mutation or diminished the frequency of producing mutant/mutant dogs.” “In over 20 years since MDR1 was identified, the breed WORLDWIDE has not altered the frequency of mutation or diminished the frequency of producing mutant/mutant dogs.” No, that was not a typo. I did that purposefully. It needed to be repeated. At the seminar the silence in the room was deafening.
Facts were presented. The most common cancer in all breeds is lymphoma and while this can be put into remission in other breeds, not so in Collies. The drug cannot be safely administered in MDR1 dogs. Even those with one copy of the gene can be negatively impacted. Once used primarily for cancer, and now often successfully used with allergies, cyclosporine is off the list for MDR1 dogs. Mutant/mutant dogs have a diminished normal metabolic response and can have an Addison’s like crisis. Beyond this, think of the new miracle medications that might not be available to MDR1 Collies. They might not be able to benefit from the modern advances of medicine. Dr. Bell put it simply, challenging, “You need to work on this. You need to move beyond testing to selecting.”
What was wonderful about the presentation was that we were not being preached to by a statistician or a dry fact ladened activist. He spoke also as a breeder who has had his own struggles to produce healthier dogs. He had empathy but did not sugarcoat what needed to be done. Breeders need to not only hear his words, but to heed them.
Two genes are needed to produce CEA. These genes are correlated to the formation of colobomas. Colobomas are predisposed to retinal detachment and both CEA and colobomas; there are various grades, or levels of severity, of both conditions. Dr. Bell stressed that we go beyond just having puppy eye evaluations done. He suggests checking as an adult because errors can be made, and a problem could be missed. Further, he highly suggests that adults be screened prior to breeding. Males should be check once annually if used at stud and bitches each time prior to breeding. Keep in mind that additional eye disorders can be and are found at those adult eye checks.
AVCO eye exams from the 1970’s showed colobomas went down from a frequency of 8% to 1%. However, current AVCO/CAER (Canine Animal Eye Registry) data shows a coloboma frequency of 9.2%. Colobomas numbers are increasing. This is where the issue of selection comes into play. Do the eye checks and select against disease. What does Dr. Bell suggest? Ask the canine ophthalmologist to be specific when evaluating your puppy’s and dog’s eyes. List the degree of affliction. If there is a coloboma, ask to diagram it.
Dr. Bell spoke with Dr. Gustavo Aguirre, the canine ophthalmologist responsible for research on Collie PRA and now working on the identification of genetic markers for Coloboma at the University of Pennsylvania. He mentioned this ongoing research. Note to readers. You and your Collies can help with this study. Collies with CEA only OR with CEA and a coloboma are needed. You dog must have had a physical eye test AND a genetic CEA test. Results from the genetic CEA DNA test can be from either Optigen or Wisdom Health. They cannot be from other genetic agencies to be part of this study. If you do not have the test, Collie Health Foundation will subsidize the test cost and also the required blood draw: 3-5 ml of whole unclotted blood in a purple capped EDTA tube, and overnight air shipment to the researchers via commercial shippers like UPS or FedEx. Do NOT use the post office. More information can be found on the CHF Website or contact Patt Caldwell.
Breed, select, replace and discard was Dr. Bell’s theme throughout the seminar. “You can keep quality while discarding disease,” he repeated while he spoke about hip dysplasia, DM, DMS. He suggests viewing Dr. Clark’s presentations on the CHF website.
Dr. Bell also spoke about the registries, CAER and OFA/CHIC. Were you aware that part of the fee you pay to have eye checks goes back into eye research? It does! Why was there a move away from CERF to CAER? The ophthalmologists wanted to record more information about what they were seeing in eye exams than CERF could handle. OFA took on the task because that is what they are in business of doing, providing a database for health. ALL eye exams are recorded and placed into a database. Cataract is recorded by age. Dr. Bell listed the percent of affliction for approximately 13 conditions of 8.566 from 2016 to 2020. Choroidal hypoplasia – is 75%, PPM iris to iris – 26.1%, normal – 16.1%, Colobomas 9.2 % Retinal dysplasia folds 8.2%, microthaphthalmia 3.6%, chorioretinal coloboma congenital at 3.4% with 5 other conditions between 1.6 and 1.2%. Dr. Aguirre said that a coloboma is a coloboma so the percentage should be 12.7%.
Looking beyond the pure number of the statistics relative to other statistics given, it must be noted that owners cannot opt out of the reporting of the data to be input into the registry. When a dog’s eyes are checked by a registered canine ophthalmologist, the results will be recorded. What breeders do with that information is quality control.
There was a plethora of information within this very short period of time. Much more can be gleaned by listening for yourself. The beauty of this is that it was recorded, and everyone can have access to it through the Collie Club of America Breed Education YouTube channel and also with the links found on the Collie Health Foundations website. Listen over and over, stop at salient points, take notes. Gather as a club and watch and then discuss. Plan strategies. Handout booklets are still available in a limited number through Kelly Neely at colliebreededucation@gmail.com
Speaking of strategies, have you entered your dogs in the OFA/CHIC database as you test? Collie Club of America tests are currently: PRA, MDR1 and DMS. Information about other test results can also be entered on the site. The data base is an amazing place to search for dogs you are looking to breed to or to incorporate into your line, but it is only as good as the information that is entered. Test your Collies and then become part of the database.
Dr. Bell’s message: “Do no harm.” “Use genetic testing for the best interests of the breed and owners.” “Quality control is genetic testing.” “Ethical breeding is performing available, required pre-breeding genetic health tests on prospective breeding stock PRIOR to breeding.” “While all genetic disease cannot be prevented, we have the knowledge and tools to improve genetic health of puppies…if not genetic screening – find a different hobby.” Indeed.
To watch Dr. Bell’s presentation, please click the video below:
At times CHF offers subsidies for certain genetic tests. Check its website often for updated information. It also subsidizes all costs for the Coloboma study which includes blood draw, vet costs for that blood draw, overnight air shipping of the blood, and an *adult eye check for dogs having CEA with no Coloboma. Dogs with a Coloboma do not need an adult eye check. The Foundation does not subsidize your original puppy eye check.
https://www.colliehealth.org/test-your-collie/
*Why do dogs with a CEA only eye check need an adult eye check? Some dogs checked as puppies as having CEA (with no coloboma), have had a coloboma show up on subsequent adult eye checks. To keep the research accurate, this needs to be noted. The Health Foundation will pay for that eye check.
Collie Health Foundation supported this seminar financially by allocating some funding through their Educational Seminar Grants Committee. Any CHF member club may apply for a health related educational grant through that committee. Information and qualifications can be found on the CHF website.
