Thispaper covers the genetic disorders found in the pure bred dogs. Wherethere have been varying debates involving the prevalence of pure breddogs to genetic disorders, it is clear that pure breeds are moreprone to genetic disorders. This paper also brings out the man-madedeformities created in dogs in the name of breed standards. Thebreed standards incorporate extreme characteristics that must beconformed to in order to achieve the required appearance (Bishop 43).The breeders are seen to concentrate more on the dogs’ appearancerather the breed health implications. In order to get rid of suchbreeds that are harmful to the dogs’ welfare and also detrimentalto the dog owner’s finances, concerted efforts to discourage thereproduction of such breeds and their consequent purchase arerequired from the animal advocates and the animal veterinaries.
Geneticdiseases in pure-bred dogs
Accordingto US pet ownership and Demographics compiled in 2012, 36% ofhouseholds in US own dogs as their pet. This translates to anestimate of 69million dogs being kept as pets in the US households.Only a minority of this dogs are cross breed dogs majority are purebred dogs. A pure bred dog refers to a dog that results from unmixedbreed over the generations.The dog breeds are said to originate fromthe wolf ancestor, therefore all modern dogs have a common ancestryas they originated from several wolf breeds which have been improvedover time. This explains the extreme size and shape found in themodern dog. Breeding of dogs started in the past with the solepurpose of creating breeds which were suitable for performingspecific tasks such as hunting, offering security as guards to humanbeings and domestic animals. Currently, people are more interestedin the looks more than the health of the dog. Today dogs are beingbred to conform to a certain breed standard of appearance (Bowling etal 73). Inorder to achieve the best Breed standards and due to thehigh demand of puppies that have various characteristics, thebreeders usually are left with no option but to mate members of thesame family inorder to come up with the puppy with all thecharacteristics as the family in question. The gene pool of membersfrom the same family is limited and does not have much gene poolvariety. The risk of genetic diseases therefore increases with eachsuccessive coupling (Suberet al 3970). Breed related diseases aremore common in pure breed dogs and may consequently lead tohighmaintenance cost due to high veterinary bills or the dogs willfinally end up being taken to rescue sanctuaries. However the generalpublic believes that the Best quality and most healthy dogs are thepure breed dogs and would pay quite a handsome amount of money to ownone. This is not usually the case and most veterinaries are awarethat the purebred dogs are traded for their looks and not theirhealth (Ostrander 97).
Dogsare second to human when it comes to genetic disorders. It has beenviewed that the pure bred dogs have higher prevalence to geneticdisorders than cross- bred dogs. This is considered to be the casebecause pure bred dogs are expected to have homozygocity which maycontain traits that are influenced by the recessive alleles(Ostrander 103). The animal welfare groups have instituted efforts todiscourage inbreeding and the Best standard criteria. This is becausethis criteria involves breeding dogs that have extremecharacteristics which they believe expose the dogs to health issues(OstranderandAnatoly 48).Just to name a few, the Dachshunds have a very long back inproportion to their legs, this expose them to spine problems. ThePekinese or the bull dog usually have a very long face thus theyexperience breathing difficulties Dog with excessively lose skinwhich may tend to form folds on their face are more prone to skindiseases and eyes irritation. Fast growing and abnormally large dogsare most likely to experience heart and bone disorders. Theinbreeding practice creates weaker genes on every successive couplingand most of them are unable to fight the above challenges especiallyif they are genetically spread. The inbreeding practise aimed atachieving maximum conformity to the Best Standard has led to manydisorders being inherited within the breed. The organizationspractising it are expected to undergo major reforms for it to besustainable.
Apartfrom the physical abnormalities, many such dogs are likely to becomefierce or uncontrollable due to breed –related instinctivebehaviour (Fischer et al 805). Many pure bred dogs are made to depictcertain behaviour such as chasing, hunting or fighting. However,people looking for pets intends to keep them as companions withoutknowing that such animals may at times suffer breed relatedinstinctive behaviour no matter how long the dog has been trained tobe a pet or the best companion. The public therefore, buy the purebred dogs out of ignorance without inquiring about their health froman expert or any unexpected behaviour that may not conform to thenorm.
Thispaper will highlight some of the common breed –related disordersthat affects pure bred dogs. There are certain congenital diseasesthat affect certain breeds of dogs while other abnormalities arepassed down by parents who have genetic abnormalities. One of theconditions is the musculoskeletal disorders. These are inheriteddisorders affecting the bones and the joints. It may affect thecervical vertebrae also known as the Wobbler syndrome, the hip joint(Hip dysplasia) or the elbow joint (elbowdysplasia) (OstranderandAnatoly 48).With wobbler syndrome, the dog suffers from abnormalities in thevertebrae and the ligaments that support the spinal cord exertingpressure on the spinal cord. The spinal cord contain the nerveswhich transfers information from the body to the brain (Kukekova etal 116). Due to this pressure on the spinal cord especially in theneck region the dog cannot coordinate the four legs, hence the namewobbler. It begins as a mild defect but as it progresses it worsens.The condition can be noted when the dog is trying to rise from alying position or to manage corners. In the long run the dog maydevelop stiff or rigid legs (OstranderandAnatoly 48).This condition is autosomal recessive. It requires a combination oftwo recessive or affected genes for it to occur. Medical managementcan be effective within a week or two but does not completelyeliminate the compression of the spinal cord. The dogs seen withthis conditions should not be bred (Petersen-Jones 1642). Even theirsiblings should not be bred because they might be potential carriersof the syndrome.
Elbowdysplasia often affects both front legs. The condition may be due toabnormal maturation of the cartilage (the connective tissue fromwhich the bone develops). Also a part of the cartilage may peel awayfrom the bone (Fischer et al 810). It is also associated withdeformities in the long bone above the elbow or deformities in theulna and the radius which make up the front leg between the elbow andthe wrist. The condition occurs when the ulna and the radius fail tofuse normally or breaks off.The deformity may also be due to anincongruent elbow, where the bones that form the joint grows atdifferent rates thus do not fit together properly. More than one ofthis condition may appear at the same time. The main cause of theelbow dysplasia is inheritance but environmental condition such asdiet, activities and trauma may play a role in the diseaseprogression (RuvinskyandSampson56). The condition is treated by surgery aimed at removing the boneor cartilage fragments or relieving the pressure at the joint.
Hipdysplasia is also a common condition that affects the pure bred dogs.The hip joint is a ball and socket form of a joint. The conditionsdevelop due to a loose ligament that hold the bones together or loosefit between the bones. Due to this loose fit, the ball may slide awayfrom the socket. If this happens repeatedly, other degenerativechanges occur in the joint. The dog will then experience a lot ofpain in the hind legs (Goldstein et al 364). The disease progresseswith time. Although there is no known cure for hip dysplasia, effortsto manage pain will be continuously instructed by the veterinaryincluding anti- inflammatory drugs and therapies (Tuntivanich et al807). Controlling dog weight by introducing proper feeding programsmay help manage the condition. The musculoskelet al disorders mostlyaffect the German shepherd, beagle, pug, bull dog, Pembroke corgi andSussex spaniel breeds (Thomas 84). The breeding companies shouldscreen the breeds for musculoskelet al disorders and should onlybreed the dogs whose mean score towards this deformities is zero.
Thepure bred dogs with short legs compared to the length of their bodiesare likely to suffer from dwarfism condition. This breeds were madeto be short and thick causing abnormal cartilage development thusthey are more prone to intervertebral disk diseases. This conditioncauses mild pains on the affected dog, poor bladder control, loss ofsensation and may lead to paralysis (Acland et al 137). Theveterinaries should inform the owners of such dogs on these riskfactors which is more likely to occur in Chondrodystrophoid breeds.On the other hand, dwarfism has been accepted as a breed standardinstead of being seen as an abnormal development feature and moredwarf dogs are likely to be produced to meet this breed criteria.This calls for the necessity of revising breed standards.
Thereis also an increased risk of bone tumours in pure bred dogs. Bonetumours develop from rapid development during early stages of growth.Some breeding clubs use growth enhancers to ensure that the dogs growvery fast to avail them for sale. The stimulated growth may lead tooverly large dogs causing stress on the bones. They may also becaused by genetic predisposition in the large and giant breeds(Acland and Aguirre 512). Bone tumours are more likely to occur inlarge bodied and heavy weight dogs. It has been proven that thetumours are less likely to occur in dogs whose weight is below 15kgs(Thomas 96). Bone tumours is expected in heavy dog breeds such as theIrish wolfhound, Great Dane and St. Bernard.
Secondly,pure bred dogs suffer from inherited eye diseases. Between 25 to 33%of the dogs in the world suffer from at least one inherited eyecondition such as diseases in the eye lens, retina, cornea and eyeball. Inherited conditions include cataracts, glaucoma which is verypainful, defects in the eye retina, eye lid and eyelash conditionswhich are generally known to cause inflammation and pain. The breedsaffected by the cataracts include the German shepherd, Cavalier KingCharles Spaniel, Irish setter, Standard Poodle, Golden retriever,Siberian Husky and BrichonFrise. Breeds affected by glaucoma includeBasset hound, Flat- coated retriever, DandieDintmont terrier andGreat Dane. There are many breed about 34 breeds affected by thedegeneration of the retina (Dikomienet al 263).
Furtherbreed related problems include ectropion which involves the rollingout of the eyelid margin exposing the mucous membrane outside. Theopposite case of this condition is known as the entropion where theeyelid margin turns inside and causes irritation to the cornea(Acland and Aguirre 512). Also eye lashes may grow in abnormalpositions. Macro palpebral fissure is an eye condition that is mostcommon in the breeds that tend to have very short or flat faces. Inthis condition, both the ectropion and entropion conditions happen atthe same time causing corneal disease. Dogs bred with loose skins onthe face may also suffer from an eye irritation condition known asnasal fold trichiasis. The dog’s hair comes into contact with theeye irritating the eye soft tissues. Cavalier King Charles Spanielbreed is suffers from eight eye problems including entropion,distichiasis, dry eye, defects in the cornea of the eye, cataract,retinal dysplasia and atrophy and multifocal defects (Gough andThomas 29). The purchaser of such breed need to be aware of thesediseases while taking care of the dogs.
Similarly,pure bred genes suffer from heart conditions and respiratorydiseases. Breathing difficulties and heart problems may causedisabilities and prevent the dog from leading a normal life. Whereasrespiratory ad heart problems are genetic, some conditions arefacilitated by the extreme features of the dogs under the pure breedcategory. For example, the brachycephalic upper airway syndrome is acondition that is most common in the brachycephalicbreeds. Thesesbreeds are known to have unnaturally short noses and flat faces. Thecondition causes obstruction in the upper airway due to the extremephysical features of the dogs in the brachycephalic breed category. They tend to have narrow nostrils, soft palate that is too long incomparison to the length of the face. Dogs with upper airway syndromeexperience difficulties in breathing and may snore noisily or becomeunconscious. They may develop chronic bronchitis and damage to theirlungs. Selective breeding to remove these deformities would be theonly long run solution. The brachycephalic breeds is also more proneto heart diseases compared to other breeds.
Theveterinaries are well aware of the fact that pure breeds are moreprone to heart diseases than mixed breeds. According to Breedpredispositions to Diseases in dogs and cats, 6.5 out of every athousand dogs suffer from dilated cardiomyopathy condition comparedto 1.6 in every a thousand dogs of mixed breed category (Gough, 33). This means that the pure breeds are four times more prone to thecondition than mixed breeds. In measuring the relative risks, dogswith a relative risk of 1 had means that there is no increased riskfor the breed, while dogs with a relative rate of 2 means that thebreed is likely to occur in the breed two times more compared to thegeneral dog population (Zhang et al 1195). The most common congenitalheart diseases in dogs are malformation of valves also known as valvedysplasia, valve narrowing( also referred to as stenosis), septaldefects( characterized by abnormal openings in the heart) patent ductarteriosus and tetralogy fallotis which results to insufficientoxygenated blood being pumped into the body. The life expectancy ofdogs with congenital heart diseases depends on the severity of thedisease (Nicholas 39). Many of them do not surpass the first year oflife if the condition is severe. If the condition is mild, they mayproceed with life beyond one year but mostly experience stuntedgrowth, frequent fainting and do not tolerate exercise especially inextreme weather conditions (BowlingandRuvinsky67). Heart failure can occur any time at any stage of their life. Atrial and septal defects can be treated via surgery. However, valvedysplasia responds poorly regardless of the mode of treatment anddogs suffering from the condition die of heart failure.
Thediagnosis efforts should be started early probably at 6 to 8 weeksbefore the dogs are released to the new homes or are used forbreeding. Early diagnosis results to early treatment of the conditionthus preventing its spread to other generations. Since the conditionsare congenital, the affected family and their siblings should not bebred as they may be potential carriers of the condition (Zhang et al1195). The risk of aortic stenosis- a condition that involves theobstruction of blood flow from the heart in dogs-is increased 5 timesfor a bull dog, 7.4times for a golden retriever. The Risk ofendocardiosis is 20.1 times for Cavalian King Charles Spaniel, 4.1times for Pekinese, 2.3 times for German shepherd. The West Highlandwhite terrier has an increased risk of 4.2 for pulmonic sterosis,13.4 for ventricular septal defect and 14.1 for Tetrallogy of Fallot(Gough 40). From the above findings. It can be deduced that purebreeds are more subjected to pain, suffering and disabilitiespertaining to heart problems than the mixed breed dogs.
Inaddition, pure breed dogs are more predisposed to a number of skindiseases, ranging from skin inflammation, open sores and skin ulcerswhich may lead to bacterial infections. Skin infections areproblematic to both the dog and the owner. The most common skindisease is known as the Seborrhoea, a disease that is caused by overproduction of skin’s sebaceous glands (Ahonen et al 67). Thesymptoms of the disease are smelly skin with itchy patches in theaffected breeds mostly the West Highland white Terrier and the CockerSpaniel. Similarly, the pure breeds are predisposed todermatomyotisis a condition that causes painful ulcers on the groins,eyelids, anus, armpits and external genitalia. The Shetland sheepdogbreeds are more predisposed to this condition. The pure breeds whichhave drooping loose skin are more predisposed to skin fold dermatitisdue to friction experienced between the skin surface resulting toskin ulcers and foul odour due to fungal infections (Zhang et al1195). The Bull dog and Pekinese will have this conditions on theirface skin folds, whereas the cocker spaniel and Springer spaniel areaffected in their lip fold. According to Gough and Thomas, theextreme physical features of the pure bred dogs also expose them toskin allergies and infections. For example, the Old English sheepdogwhich is designed to have fur on its feet has an increased risk of28.9 times to suffer from feet infections (Gough 43). It is clearthat the enhanced physical features of the pure bred dogs exposesthem to skin allergies and infections. Boxers have an increased riskof 5.8 times for allergic skin diseases and 4.3 times for foodhypersensitivity, while Golden retrievers have an increased risk of2.3 to allergic skin diseases (Gough, 43). Therefore, there is needto revise the breed standards in order to reduce skin allergies andinfections. Breed standards encouraging skin folds should not beadopted as they damage the dogs’ welfare.
Lastly,the pure breed dogs are predisposed to hereditary deafness. It isonly possible to quickly identify a dog that is completely deaf butknowing the dog is partially deaf will require an assessment by a dogspecialist or a veterinary. Hearing is core factor to consider whenbreeding dogs or buying a dog from the breeders. This is because adeaf dog is very hard to train and reacts aggressively when scared. It is most likely to be hit on the road thus more prone to accidents(Goughand Thomas59). The Dalmatians are predisposed to hereditary deafness. Otherbreeds affected by the deafness include the English Cocker spanielsand White Bull terriers though at small percentages. Similarly, purebred dogs are likely to suffer from auto immune disorders which isdepicted by failed immune system (Dekomien 263). This causes the dogsto experience frequent anaemia, poly arthritis and thyroid diseases.
Animalwelfare organizations should educate people on the disorders causedby the extreme characteristics which they prefer in dogs. Throughtraining, people will not push the demand of such breeds andtherefore their supply will be unnecessary as the people who designthe breeds mostly respond to consumers’ needs (Dekomien 263).Physical characteristics such as skin folds, extremely short legs andextremely long backs, extremely flat face and protruding eyes areamong the physical features which are prone to hereditary disordersand should therefore be discouraged if not Prohibited (Ostrander 89).These extreme characteristics are detrimental to the health and theanimals’ welfare. Most of the time, people order for certainbreeds because of the pleasant looks without considering the healthimplications. Puppy buyers should only purchase their puppies frombuyers who screen their dogs and provide a contract of their courseof action if the dog develops preventable disorders or disorderscaused by their physical features, they should do so by obtaining acertificate of such screening from the breeders.
TheAnimal welfare group should educate the general public on theimportance of inquiring about the breed history, physicaldescription, common illnesses and its prevalence to certain disordersas earlier discussed so that they are aware of the financial burdenthey might get into if they choose more susceptible breeds. Forexample: A person intending to acquire the English bull dog should beinformed of its physique its English Bull dog has a short body with loose skin on the head, neck and shoulders. It tends to shufflesideways while walking and has loose joints. Due to its physicalcharacteristics, the Bull dog is more prone to hip and Knee capdysplasia. It has relatively narrow hips thus delivers via caesareansection and its unable to mate thus litters are conceived viaartificial insemination. They react adversely to extreme heatconditions.
TheAnimal health regulatory bodies should also set regulations on thetype of breeds to be produced to prevent them from being exposed tounnecessary pain and disorders. They should come up with guidelinesdefining the standards that must be complied to, in designing thebreeds. Specifications such as the minimum and maximum values ofheight and weight depending on the size of the dog (Ostrander 89).This will prevent skeleton and joint disorders. They should also setstandards on the minimum and maximum length of dogs. Other featuresto be standardized may include the set limits of the size of theskull, nose and the tracheal system to prevent the breathingdifficulties and blockage of the ducts in the respiratory system.They should also standardize the size of the ears and avoid foldedskin. Folded skin is more prone to eczema, skin inflammations andirritation.
Veterinariesalso should come up and voice their concerns. This is because theyare mostly involved in the treatment of these disorders so they areaware of the pain and sufferings that the pure bred dogs are exposedto. Advocates believe that veterinaries and the general public havean important role to play to improve the welfare of dogs (Wolf et al1332). They therefore require the veterinaries to be proactive andeducate dog owners of the risks of purchasing a pedigree dog. Theyshould inform the general public on why they should not support thepedigree dog’sproduction by either purchasing or attending the dogshows as they are better placed in their profession to make influencethe innocent dog owners’ decisions (WrayandWray65).
Inconclusion, pure breeding has led to many challenges in the welfareof both the dogs and the owners. The main goalof the breeders focusesmore on the appearance and is aimed at achieving the breed standardwithout worrying of the health of the dog. This has led to majorabnormalities,many predisposed and inherited disorders. The healthdisorders are more prevalent in pure bred dogs because their physicalcharacteristics that are said to conform to the breed standards areclose to physical abnormalities and they cause health problems indogs. This conditions have created a major burden of ill- health andsuffering to dogs and financial cost to dog owners. Similarly,inbreeding also restricts the gene pool for the breed therebyincreasing the likelihood of inheriting affected genes consequentlysuffering from inherited diseases (Suber 3969). Proper screeningshould be done on all dogs that are used for breeding so as toeliminate breeds that are suffering from inherited disorders or arecarriers of the recessive genes which may be transferred to theirsiblings. Efforts by the breedsocieties to promote screening couldhave led to reduction in the hereditary disorders. However, thoughthey offer the screening of some disorders at no cost, the screeninghas not been effective as it is not mandatory (Winkler et al 78). TheAnimal welfare regulatory bodies should make it mandatory to screenfor the life threatening disorders in order to complement the effortsof the breed societies to reduce these disorders. It is alsoappropriate to revise the breed standards for extreme physicalcharacteristics which results to abnormalities in the affectedbreeds. Animal advocates believe that the standards can be revised toremove the characters that do not conform to welfare of the dogs. Inorder to reverse the damage caused by inappropriate pedigreebreeding, the breeders clubs should incorporate mixed breeds in theirbreed standards. Also, they should revise their primary goal to bemore concerned about the dog’s health other than its physicalcharacteristics and outer beauty. The breeding clubs and societiesshould be able to produce a certificate of the results of screeningthe parent dogs when registering puppies and these records should bemade available for the public.
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