The Genetic Health of the�Bearded Collie

Jerold S Bell, DVM

Cummings School of Veterinary Medicine

at Tufts University

Olympia, WA - Sept.22, 2021

Practical Genetics for Bearded Collie Breeders & Owners

Jerold S Bell, DVM

Cummings School of Veterinary Medicine

at Tufts University

A large number of individuals in a breed population provides greater choices when making breeding decisions

With each selected trait or disorder, the proportion of the available gene pool decreases

SELECTION

Registration Statistics of the Bearded Collie

AKC Population Growth

Year AKC Rank # of dogs registered

2020 125 216

2019 ? 156

2018 127 184

2017 112 184

2016 121 212

2015 119 230

2014 126 272

2013 125 306

2012 96 247

2011 107 315

2010 112 300

2005 101 485

2000 92 682

1995 87 762

1990 79 700

1985 72 887

AKC Litters Registered

Year Litters

2020 49

2019 40

2018 45

2017 44

2016 58

2015 51

2014 68

2013 79

2012 64

2011 76

2010 79

2005 ?

2000 196

1995 189

1990 172

1985 189

Pups Reg/Lit

4.4

3.9

4.1

4.2

3.7

4.5

4.0

3.9

3.9

4.1

3.8

?

3.5

4.0

4.1

4.7

AKC Bearded Collies Bred

Bearded Collies = 8.9%

http://siriusdog.com/bell-pedigree-analysis-genetic-diversity

The Ins and Outs of Pedigree Analysis, Genetic Diversity, and Genetic Disease Control

Types of Matings

• Inbreeding: Breeding closely related dogs.
• Linebreeding: Less intense form of inbreeding. Concentrating the genes of a particular ancestor.
• Outbreeding: Breeding dogs less related than the average of the population.
• Crossbreeding: Breeding two different breeds together.

Pure-bred

Designer breed

Random-bred

Inbreeding Coefficient�(Wright’s Coefficient = Fx)

• The proportion of all variable gene pairs that are likely to be homozygous due to inheritance from ancestors common to the sire and dam.
• The probability of an individual being homozygous at a given gene pair for a gene received from an ancestor common to the sire and dam.

Relationship Coefficient

• A measurement of the probable genetic likeness between the individual and a particular ancestor
• The probable percentage of genes the individual and the ancestor have in common from descent
• Can be approximated by % blood calculation

Bearded Collie�Inbreeding Coefficients Over Time

Bearded Collie�Inbreeding Coefficients Over Time

Breed Inbreeding Coefficients

Breed Period 10 gen. coefficient

American Cocker Spaniel 1980-1999 10.49 +/- 7.33

Bichon Frise 1990-2004 19.55 +/- 7.68

Bernese Mountain Dog 1990-1999 11.32 +/- 4.50

Borzoi 1990-1999 10.48 +/- 8.85

Bouvier des Flandres 1990-1999 13.96 +/- 5.92

Briard 1976-1993 15.18 +/- 7.66

Bull Terrier 1990-1999 19.01 +/- 6.23

Cavalier King Charles Sp. 1990-1999 13.17 +/- 5.83

English Pointer 1990-2005 17.00 +/- 8.07

German Shorthaired Pointer 1990-1995 11.12 +/- 8.50

Great Pyrenees 1985-1990 17.76 +/- 9.17

Irish Setter 1990-2002 15.81 +/- 5.84

Mastiff 1990-1999 11.59 +/- 6.57

Norfolk Terrier 1990-2000 29.79 +/- 7.32

Nova Scotia Duck Tolling Ret. 1990-1999 27.17 +/- 4.48

Poodle, Miniature 1980-2000 16.50 +/- 7.86

Poodle, Standard 1980-2000 16.25 +/- 7.77

Rhodesian Ridgeback 1990-1999 15.91 +/- 6.15

Samoyed 1990-1999 9.94 +/- 7.64

Siberian Husky 1990-2000 15.47 +/- 6.99

Embark COI Analysis

Bearded Collie�AKC Inbreeding Coefficients Over Time

INFLUENTIAL Bearded Collie ANCESTORS

INFLUENTIAL Bearded Collie ANCESTORS

INFLUENTIAL Bearded Collie ANCESTORS

INFLUENTIAL Bearded Collie ANCESTORS

INFLUENTIAL Bearded Collie ANCESTORS

INFLUENTIAL Bearded Collie ANCESTORS

INFLUENTIAL Bearded Collie ANCESTORS

5 gen IC=11.9%

All gen IC=30.5%

10 gen IC=26.9%

Pedigree Analysis for Tolkien Raintree Mister Baggins�I.C.= 11.9%/26.9%/30.5%

Linebred Ancestors % Blood 1st Gen. #Times

Ha’Penny Carob Week’nd Warrior37.5% 2 2

Bailie of Bothkennar 32.4% 10 9,685

Bra’Tawny of Bothkennar 23.9% 10 2,677

Windfiddler Bound To Be A Star 21.9% 3 3

Ridgeway Rob 21.8% 10 2,338

Ha’Penny Blue Blossom 21.1% 5 10

Osmart Bonnie Blue Braid 19.6% 7 118

Bravo of Bothkennar 17.7% 8 290

Chauntelle Limelight 17.2% 5 9

Ha’Penny Moon Shadow 15.6% 4 3

Blue Bonnie of Bothkennar 14.9% 8 202

Wishanger Cairnbhan 14.7% 8 216

Edenborough Blue Braken 14.4% 6 31

Potterdale Double Image 14.1% 4 5

5 gen IC=1.1%

All gen IC=24.3%

10 gen IC=19.6%

Pedigree Analysis for Sweetwater’s Pink Ribbon�I.C.= 1.1%/19.6%/24.3%

Linebred Ancestors % Blood 1st Gen. #Times

Bailie of Bothkennar 32.9% 10 21,823

Bra’Tawny of Bothkennar 24.6% 10 6,063

Ridgeway Rob 22.8% 10 5,355

Osmart Bonnie Blue Braid 19.9% 7 225

Wishanger Cairnbhan 18.2% 8 513

Bravo of Bothkennar 18.2% 8 593

Blue Bonnie of Bothkennar 15.6% 8 411

Blumberg Hadriana at Potterdale 15.5% 6 34

Willowmead Barberry of Bothkennar14.3% 9 2,531

Jeannie of Bothkennar 14.1% 11 13,853

Potterdale Philosopher 13.8% 5 21

Wishanger Barley of Bothkennar13.3% 9 990

Bond of Bothkennar 13.0% 9 1,907

Bess of Bothkennar 12.6% 10 7,562

5 gen IC=18.2%

All gen IC=37.1%

10 gen IC=34.9%

Pedigree Analysis for Pentangles Captain Jack �I.C.= 18.2%/34.9%/37.1%

Linebred Ancestors % Blood 1st Gen. #Times

Britannia Bobby Dazzler 37.5% 2 2

Pentangle’s Kiss Me Now 37.5% 2 2

Bailie of Bothkennar 32.6% 9 17,190

Shilstone Charlie Charcoal 25.0% 3 3

Bra’Tawny of Bothkennar 24.7% 9 4,782

Blumberg Hadriana at Potterdale 24.2% 5 20

Ridgeway Rob 22.7% 9 4,217

Potterdale Double Image 21.9% 4 9

Osmart Bonnie Blue Braid 21.0% 6 186

Wishanger Cairnbhan 18.8% 7 393

Potterdale Anderson at Ramsgrove 17.2% 5 12

Bravo of Bothkennar 15.8% 7 423

Britannia Ticket to Ride 15.6% 4 3

Willowmead Barberry of Bothkennar15.4% 10 2,064

Inbreeding Coefficients� vs. Depth of Pedigree

In order to understand about breeds, you must understand about breed evolution

As breed lines became more specialized and stud books closed, those who did not conform to the standard were removed from breeding

The development of breeds occurred through artificial selection for body type, color, coat type, behavior, and conformational aspects

Studies of dog breeds estimate that they lose on average 35% of their genetic diversity through breed formation

(Gray MM et. al. Genetics 2009; 181:1493-505)

Pedigree Analysis of Populations

A typical Bearded Collie pedigree

Any selection over generations will create

• Homozygosity – uniform purposeful selection for breeding goals
• Diminished frequencies of undesirable genes

Any selection will cause a loss of genetic diversity

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​

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This loss is not detrimental to the population, if it is directly related to increasing its superiority

Breed-defining genes would be expected to become homozygous due to selection over time

These include breed-selected traits for size, coat color & texture, behavior, skeletal morphology, and other traits

Even without close linebreeding, selection for positive traits will increase their homozygosity having originated from distant ancestors

Modern Breed Population Statistics

• High deep pedigree average inbreeding coefficients (homozygosity)
• Low effective population size (limited number of founders)
• High average relationship coefficients to influential ancestors
• These ancestors appear in the pedigrees of every member of the breed, with genetic contributions of 15%-35%

These are necessary and expected consequences of breed formation and evolution

Homozygosity is not inherently correlated to impaired genetic health, nor does it need to be artificially controlled

Healthy Breed Genes Pools Require Expanding, or Large Stable Populations

​

• Allows the creation of new “family lines”
• Allows for within-breed diversity
• Population contraction causes loss of breed diversity and quality breed lines

Selection of breeding animals should represent the quality traits and breadth of pedigree background

​

Quality lines should not be abandoned

The Popular� Sire Syndrome

The popular sire syndrome is the single most influential factor in restricting breed gene pool diversity

• The overuse of a popular sire;
• Quickly disseminates his genes throughout the gene pool without the benefit of evaluation over time
• Causes the loss of other quality male lines that should be contributing to the gene pool

A popular sire’s influence is different from that of an influential ancestor

• An influential ancestor’s contribution is continually evaluated through it’s descendants, who have to compete with others for breeding status
• If a popular sire is found to pass on deleterious genes, the resultant purging process also causes the loss of influence of the quality dam lines to which he was bred

Diseases and Disorders

The Dark Side of Breed Development

All individuals carry some deleterious mutations

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• Quality individuals who propagate will also propagate their deleterious mutations
• These can cause breed-related disease if they are disseminated and increase in frequency through the founder’s effect

Breed propagation must always include active monitoring and selection against genetic disease

​

Without this selection, the genetic health of the breed will decline

The genetic health of dog breeds is not a direct function of homozygosity or heterozygosity, but of the accumulation of specific disease liability genes

Breed Maintenance

In response to perceived concerns with genetic diversity, some advocate for homozygosity testing and SSP-type outbreeding programs

Recommendations to only outbreed (breed to those least related) homogenizes breeds and erases the genetic difference between individuals

None of the types of mating systems (Inbreeding, Linebreeding, Outbreeding) change the frequency of defective genes, or their dissemination

Outbreeding will not change the frequency of deleterious genes

• For dispersed breed-related deleterious genes, outbreeding will not reduce the frequency of affected individuals
• Affected individuals will be produced in a random fashion

Genetic Diversity

• Molecular geneticists have discovered the tools to identify homozygosity within breeds
• In identifying these tools, molecular geneticists are instructing breeders to use these tools as goals of breeding and only outbreed to unrelated dogs and increase their “genetic diversity”

​

Genetic Diversity

• All breeds are inbred with many different parameters causing changes in their homozygosity and genetic diversity
• None of the manipulations recommended by molecular geneticist have to do with:
• The health of the breeds
• Selection for or against specific health or diseases or liability genes

Recommendations to increase

the diversity of MHC haplotypes

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• In no breeds has general limited MHC diversity or random homozygosity been shown to impair breed immunity
• All studies of autoimmune disease, immune deficiency, or pathogen susceptibility identify specific MHC haplotypes or disease related genes

Selection for Heterozygosity

• Selects against good homozygosity accomplished through generations of selection
• Blindly increases minor frequency genes and chromosomal segments
• These are likely minor frequency due to selection over generations against undesirable and deleterious traits

Genetic Diversity�=�Breeder Diversity

It is the varied opinion of breeders as to what constitutes the ideal animal, and their selection of breeding stock that maintains breed diversity

When breeds have issues with genetic disease, the only way to improve their gene pool is through genetic screening and selection against the specific diseases and their associated liability genes

Moderation away from extremes that cause disease should be a guiding principle in breeding and judging

Pre-breeding Health Screening

should become as

universal as

Equine Pre-purchase Exams

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1) Avoiding the popular sire syndrome.

2) Utilizing quality dogs from the breadth of your population to expand the gene pool.

3) Monitoring genetic health issues through regular health surveys.

4) Doing genetic screening for breed-related disorders.

5) Participating in open health registries to manage genetic disorders.

6) Constant selection for quality and health

Breed Maintenance Requires;

DEVELOPING A HEALTHY�BREEDING PROGRAM

Breeding Goals

• Maintain and enhance the quality of the breed
• Do not limit the genetic diversity of the population
• Genetic Disease Control
• Do not produce affected animals
• Decrease the (carrier) frequency of defective genes

Genetic Screening and Genetic Testing

• Tests of the genotype: Direct DNA tests for liability genes
• Tests of the phenotype: Tests to primarily identify clinically affected individuals
• Pedigree analysis: Identification of carrier risk based on the knowledge of carrier and affected relatives

• Mutation test results for 150+ genetic diseases.
• Testing for more than 20 traits including coat colors, coat types, and morphology.
• Genetic diversity testing.
• Cheek swab test costing $130-$199.
• Uses SNPs – doesn’t check for mutations
• Requires knowledge of what test results are relevant to the tested individual (breed).

Genetic Panel Screening

International Partnership for Dogs���https://dogwellnet.com/ctp/�

• Test % Tested
• Hips 36.7% *
• Eye Examination 19.8% *
• Thyroid 11.0% *
• Elbows 10.3% ^
• CEA/CH 6.8%
• MDR-1 1.7%

* CHIC Requirement ^ CHIC Optional

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BeaCon Open Health Registry�Health Testing (3,309 dogs)

Bearded Collie�OFA On-line Health Survey (180 dogs)

• Test % Tested
• OFA Thyroid Panel 55.0% *
• OFA Eye Exam 46.9% *
• OFA Hips 39.4% *
• OFA Elbows 27.5% ^
• CEA DNA Test 27.5%
• OFA Hips – prelim 15.6%
• CHIC DNA Repository 15.0%
• Hips-Other 5.0% *
• * CHIC Requirement ^ CHIC Optional

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�

Top 10 Canine Health Concerns�(AKC Canine Health Foundation)

#1 Hip Dysplasia

#2 Epilepsy

#3Allergies

#4 Hemangiosarcoma

#5 Hypothyroidism

#6 Lymphoma

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#7 Gastric Dilitation-

Volvulus/Bloat

#8 Patella Luxation

#9 Cruciate Ligament Rupture (ACL)

#10 Inflammatory Bowel Disease

Next 10 Canine Health Concerns�(AKC Canine Health Foundation)

#11 Cataracts

#12 Osteosarcoma

#13 Atopic Dermatitis (Atopy)

#14 Elbow Dysplasia

#15 Immune-Mediated Hemolytic Anemia

#16 Cardiomyopathy

#17 Progressive Retinal Atropy (PRA)

#18 Mammary Tumors

#19 Cryptorchidism

#20 Mitral Valve Disease

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BeaCon Open Health Registry�Health Issues (3,309 dogs)

• Fear 8.4%
• Hypothyroidism 5.3%
• Symmetrical Lupoid Onychodystrophy 3.7%
• Athritis 3.1%
• Addison’s Disease 3.1%
• Umbilical Hernia 2.2%
• Hip Dysplasia 2.2%
• Pyometra 1.7%
• Food Allergy/Intolerance 1.6%
• Urinary Tract Infection 1.6%

• Cataract 1.4%
• Depigmentation 1.4%
• Hearing Loss 1.4%
• Cushing’s Disease 1.2%
• Aggression 1.2%
• Inflammatory Bowel Dz 1.2%
• Vestibular Disease 1.2%
• Kidney Failure 1.2%
• Auto-immune Hemolytic Anemia 1.1%
• Atopy/Allergies 1.0%

OFA Bearded Collie On-line�Health Survey (180 dogs)

• Arthritis 6.3%
• Other Immune Dz 3.8%
• Prostatitis ♂ 3.8%
• Hip Dysplasia 3.1%
• Hypothyroid 3.1%
• Pyometra ♀ 2.8%
• Cataracts, senile 2.5%
• Inflammatory Bowel Dz 2.5%
• Food Allergy 2.5%
• Autoimm. Hemolytic Anemia 2.5%

• Sterility ♂ 1.9%
• Lipomas 1.9%
• Sebaceous Cysts 1.9%
• Hemangiosarcoma 1.9%
• Ovarian Cysts ♀ 1.4%
• Addison’s Disease 1.3%
• Heart Murmur 1.3%
• Mammary Cancer ♀ 1.3%
• Contact Allergies 1.3%
• Inhalant (atopy) All. 1.3%

Ocular Disorders in the Bearded Collie�(Based on ACVO Examination of 479 dogs examined between 2015-2019)

DISORDER % (# of dogs)

• Normal 68.5% (328)
• Cataract, Significance Unknown 12.9% (62) *
• Cataract, Significant 12.7% (61) *
• Persistent Pupillary Membrane (Iris to Iris) 4.2% (20)
• Cataract, punctate anterior cortex 1.5% (7)
• Distichiasis 1.5% (7)
• Cataract, punctate posterior suture 1.3% (6)
• Corneal Dystrophy 1.0% (5)

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* ACVO does not recommend breeding any Bearded Collie with a cataract or Collie Eye Anomaly (choroidal hypoplasia)

Hypothyroidism in the �Bearded Collie

• Diagnosis of autoimmune thyroiditis
• not just thyroid responsive conditions
• Dogs with measurable antibodies are affected
• 4.3% of 793 Bearded Collies tested by Michigan State University are positive for TgAA. Average for all breeds = 7.5%
• 6.6% test equivocal

1,069 dogs registered

87.8% Normal (939 dogs)

1.5% Affected (16 dogs)

10.7% Equivocal (114 dogs)

OFA Thyroid Statistics for the

Bearded Collie

• Hereditary Autoimmune Thyroiditis
• A thyroid profile is a snapshot of a continuous disease process
• Range of 2 - 6 years, with peak levels at 4 years of age
• After thyroid gland destruction, autoantibodies diminish & left with end stage hypothyroidism

Hypothyroidism in the �Bearded Collie

Canine Hip Dysplasia

OFA Hip Statistics for the �Bearded Collie

Rank 148/191 (5,037 radiographs)

93.7% Normal

17.8% Excellent (15.7% for all breeds)

64.8% Good

11.1% Fair

5.7% Dysplastic (11.4% for all breeds)

3.3% Mildly Dysplastic

1.8% Moderately Dysplastic

0.6% Severely Dysplastic

OFA Hip Statistics for the�Bearded Collie

Trends:

Range # submitted Excellent Dysplastic

Prior to ‘90 1,733 11.4% 8.9%

‘91-’95 870 16.0% 4.6%

’96-’00 776 16.5% 6.3%

‘01-’05 675 22.5% 4.3%

‘06-’10 518 25.9% 4.8%

’11-’15 361 27.4% 2.2%

’16-’18 145 31.7% 4.8%

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Elbow Dysplasia

OFA Elbow Statistics for the� Bearded Collie

Rank #92/135 (939 evaluations)

97.2% Normal

2.6% dysplastic:

1.9% Grade I (18 dogs)

0.5% Grade II (5 dogs)

0.1% Grade III (1 dog)

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Collie Eye Anomaly (CEA): Choroidal Hypoplasia

• Inadequate development of the choroid area of the retina present at birth and non-progressive
• Autosomal recessive inherited disorder
• 5% - 10% of affected dogs can progress to vision loss from:
• Retinal detachment
• Retinal hemorrhage (bleeding)
• Genetic test is available
• PawPrint Genetics Testing (241 BC)
• 87.1% Normal 12.0% Carrier 0.8% At Risk
• Embark Testing (218 BC)
• 95.4% Normal 4.6% Carrier 0% At Risk

Hypoadrenocorticism (Addison’s disease):

• Immune-mediated destruction of the adrenal gland
• Typical presentation of lethargy, poor appetite, vomiting, weakness, and dehydration
• Onset usually 4 months to several years of age.
• Treatment with DOCA injections or oral fludrocortisone
• Complexly inherited with a (unidentified) major recessive gene
• Estimated heritability of 76%
• Estimated at a frequency of 2% to 3.4% in the Bearded Collie

​

Hypoadrenocorticism (Addison’s disease):

• Research
• Drs. Oberbauer & Gershony group (UC-Davis)
• Genome Wide Association Study (GWAS) in Bearded Collies (55 cases, 85 controls)
• Significant association to a region on chromosome 18 with additional small associations to regions on chromosomes 11,16, & 29
• Some of these associations may be causative (liability) genes and some may be regulatory (on/off) genes – none specifically identified

Hypoadrenocorticism (Addison’s disease):

• Research
• Drs. Oberbauer & Gershony group (UC-Davis)
• Having more than one chromosomal marker significantly increased risk for AD - additive effect?
• Only 10% of affected BC had all 4 markers
• No association to chromosome 12 (MHC)
• Still more research needed to identify specific genes

Gershony et. al. BMC Genomics (2020) 21:833 Genetic characterization of Addison’s disease in Bearded Collies

Symmetrical Lupoid Onychodystrophy (SLO)

• Immune-mediated disorder causing loss of toenails
• Onset between 3-8 years of age, affecting 1-2 nails, then progressing to all toenails within 2-9 weeks
• Requires lifelong treatment with oral fatty acid supplementation +/- other meds
• Complexly inherited caused by more than one susceptibility or liability gene pair

Symmetrical Lupoid Onychodystrophy (SLO)

• Genetic studies into SLO inheritance in BC
• Two DLA Class II haplotypes (3 gene combinations in the MHC) are highly associated with being affected with SLO in the BC
• Additional genes have been identified as associated with SLO, but all are close on chromosome 12 and linked to the DLA genes
• Another location on chromosome 17 is also highly associated with SLO in Bearded Collies, but specific genes in this region have not been identified

Gershony et. al. Genes (Basel). 2019 Aug 22;10(9):635.

Gershony et. al. Genes (Basel). 2021 Aug 19;12(8):1265.

Immune Mediated Hemolytic Anemia

• Auto-immune disease where the body’s immune system attacks and destroys its own red blood cells.
• Slightly increased female preponderance.
• Complexly inherited.
• No genetic test exists.
• Dr. Steven Friedenberg (UMinn) is working to identify gene mutations responsible for the development of IMHA.

Mdr-1 Drug Sensitivity

• Autosomal recessive disorder in the MDR1 gene allows high brain levels of many drugs
• Ivermectin, doramectin, loperamide, vincristine, moxidectin, and others
• Causes neurological signs, including tremors, seizures, and coma.
• Mutation found primarily in Collie related herding breeds
• A genetic test is available for the mutated gene
• Occurs at a very low frequency in Bearded Collies
• Not found in worldwide study of 438 BC
• Gramer et. al. Vet J. 2011 Jul;189(1):67-71.
• One of ten BC in Italian study was a carrier
• Marelli et. al. Vet Rec Open. 2020 Jun 24;7(1):e000375.

Other Inherited Disorders

• Primary Lens Luxation
• Occurs at an increased frequency in the breed. Often progresses to secondary glaucoma and blindness. Reported increased risk versus other breeds
• Pemphigus Foliaceus
• Autoimmune skin disease causing symmetrical scaling, crusting and hair loss to the head and muzzle and footpads usually around 4 years of age
• Seasonal Flank Alopecia
• Seasonal, bilateral, symmetrical hair loss affecting the flank, back and tail

Responsibility

Duty, Obligation, Burden

What is the obligation for breeders

to do genetic testing?

Breeders are the custodians of their breeds, and their gene pool.

• Above all, do no harm.
• Breeders must be counseled to use genetic tests for the best interests of their breed.

What is the Expectation of the General Public?

That Quality Control for Genetic Disease

Is Being Done

It is the ethical responsibility and obligation of all breeders to perform the available required pre-breeding genetic health tests on prospective breeding stock prior to any breeding

All genetic disease cannot be prevented. However, we have the knowledge and the tools to improve the genetic health of puppies

Who is a Reputable Breeder?

One That Does Genetic Screening

If not: Find a different hobby

or profession

Many health tests can be performed during an examination with your veterinarian, or obtained inexpensively at local health screening clinics

www.offa.org/clinics.html

www.cavalierhealth.org/health_clinics.htm

Updated February 16, 2013 −328 Clinics Listed!

Managing Genetic Disease

Managing Dominant Genes

• Ex) Ehlers-Danlos syndrome, Goiter, Lymphedema, some Cataracts, Mastiff PRA.
• Replace affected breeding dogs with normal siblings, parent, or prior-born offspring.
• Ideally don’t want to breed and produce more affected dogs.

Managing Recessive Genes

• Ex) storage diseases, Von Willibrand’s disease, Cranomandibular Osteopathy (CMO), CMR.

With tests for carriers:

• Breed carriers to genetically normal mates.
• Replace carrier parents with genetically normal offspring.
• Select against carriers for breeding.

The Proper Use of�Genetic Tests

• Without genetic tests, the effect of selection on the gene pool is minimal.
• With genetic tests, if everyone decides not to breed carriers, it can have a significant limiting effect on the gene pool.

If a breeder was planning on breeding an animal prior to receiving carrier test results, the PROPER RESPONSE is to breed to a normal individual, and eventually replace the parent with a quality normal offspring.

An individual is not an eye, a hip, or a heart. Each individual carries tens of thousands of genes, and each is part of the breed’s gene pool.

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Breeders must consider all aspects, such as health issues, conformation, temperament, and working ability.

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Making breeding decisions based on a single testable gene is inappropriate.

For RECESSIVE diseases

A DIRECT GENETIC TEST

should not alter

WHO gets bred, only

WHO THEY GET BRED TO.

Genetic Registries

www.ofa.org

Advancing the health of all breeds through DNA collection for research.�Banking On Your Future

There are currently 72 Bearded Collie DNA samples in the CHIC DNA Repository

(29 blood and 43 cheek swab)

The Standard of Care in Health Conscious Breeding

OFA – The Canine Health

Information Center

• Open health database for breeds.
• Included disorders and means of diagnoses are determined by each national breed club.
• Animals can receive CHIC certification based on completing the required genetic testing, REGARDLESS of normal or abnormal outcomes.
• As more testable disorders emerge, every individual is likely to carry some deleterious genes.

CANINE HEALTH

INFORMATION CENTER

Not about health normalcy

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About health consciousness

CANINE HEALTH

INFORMATION CENTER

569 Bearded Collies have achieved CHIC certification

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CHIC Breed Ratio 2015-2017

(#CHIC/#Bred)=0.42%

Average CHIC Ratio of

Middle 1/3 population of breeds = 11%

Bottom 1/3 population of breeds = 16%

Bearded Collie CHIC Ratio = 42%

https://www.ofa.org/advanced-search?f=sr&appnum=1888967

Bearded Collie�OFA Hip Open Health Reporting

Year % Open

2001 10.0%

2002 18.3%

2003 9.4%

2004 18.1%

2005 16.7%

2006 18.7%

2007 22.8%

2008 16.1%

2009 20.0%

2010 13.2%

2011 14.3%

2012 16.5%

2013 13.9%

2014 12.3%

2015 21.4%

2016 25.7%

2017 22.7%

2018 15.2%

2019 25.6%

2020 25.0%

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Ave. for

all breeds

=23%

“As long as we keep problems ‘secret’ we will not be able� to deal with them.”

Breeders need to be informed about the problems occurring in the offspring they produce

The days of stigmatizing conscientious, health-testing breeders who have�produced dogs affected or carrying hereditary disease are over

Using Genetic Tests

Direct Gene Test

• Test of the genotype
• Only need to know results of the breeding stock to make breeding decisions

Phenotypic Tests, Linkage tests, or No test for carriers

• Knowledge of the test results and carrier or affected status of relatives is important

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Without tests for carriers

• Breed higher risk individuals to lower risk individuals.
• Replace the higher risk individual with it’s lower risk offspring.
• Repeat the process in the next generation.
• Requires (open) health databases

Managing Sex-linked Genes

• Ex) hemophilia A & B, muscular dystrophy, Siberian Husky/Samoyed PRA.
• Follow the same “breed and replace” recommendations, for autosomal recessive genes, except:
• Using normal males will always lose the defective gene
• Affected males have carrier mothers, and all carrier daughters
• Carrier mothers have 50% affected sons
• Replace carrier females with normal male sibs or male offspring

Managing Polygenic Disorders

• Ex) congenital heart anomalies, hip dysplasia, patella luxation
• Identify phenotypic traits tied to the underlying genes
• Phenotypic breadth of pedigree provides information on the possible range of genes carried
• Treat disorders as threshold traits
• Breed normal dogs from (mostly) normal litters

Depth of Pedigree

Breadth of Pedigree

?

Polygenic disorders are Threshold Traits

A number of genes must combine

to cross a threshold to produce

an affected animal.

Threshold Traits

x

3+1

4+2

5+1

=

=

=

x

2+3

1+1

0+1

=

=

=

Keller, Dziuk & Bell: Veterinary Journal, August, 2011

Keller, Dziuk & Bell: Veterinary Journal, August, 2011

• Identify carriers or risk of carrying disease liability genes
• Work to breed away from the defective gene(s)
• Prevent the reintroduction of the gene(s) in future breedings

Breeders should use health screening tests to :

Each breeder must assess their own breeding stock and determine their own rate of progress

• Replace carriers with normal-testing offspring
• Decrease carrier frequency or carrier risk with each generation

A Healthy Breeding Program

• Does not continually multiply carriers
• Does not limit the genetic diversity of the population
• Is geared toward producing quality, genetically normal dogs

How Can We Educate the Public?

• Make them more informed consumers of dogs and puppies
• Able to discern responsible breeders
• Knowledgeable about genetic testing

Questions?