Yorkshire Terrier

By | 2009-10-18

Origin of the dog breed: Scotland/England

Size of dog: 8 to 9 inches 7 to 8 pounds

Dogs coat: Shiny, soft, long & straight

Color of dog: Steel blue and tan

A toy breed with unusual beauty, the Yorkie was used originally in the mines as a ratter. In those days the breed was larger and heavier. Some of the aggressiveness has remained in the breed. It is a lovable and clever companion enjoying the presence of older people. Because of its size, it can be fragile.

This dog breed is prone to: Patellar luxation; eye problem.

Dog Breed Predisposition to Conditions, Diseases and Disorders

Cardiovascular conditions

Patent ductus arteriosus

• Common congenital abnormality

• Relative risk 4.2

• Mode of inheritance is polygenic

Endocardiosis

• Also known as chronic valvular disease

• Relative risk 2.6

• Increased prevalence with age

• Aetiology unknown but genetic basis likely

Dermatological conditions

Rabies-vaccine-associated vasculitis and alopecia

• Lesions appear at site of vaccine 3-6 months after administration

Short-hair syndrome of Silky breeds

• Usual onset: 1-5 years

• Cause unknown

Cyclic follicular dysplasia

• Seems to be a particular problem in Alaska, suggesting duration of daylight exposure may be a factor

Ichthyosis

• Rare

• Congenital

• Possibly inherited as an autosomal recessive trait

Congenital hypotrichosis

• Present at birth or develops in first month of life

• Predisposition for males suggests sex linkage

Colour-dilution alopecia

• Coat-colour genes involved in the pathogenesis

Melanotrichia

• Often follows healing of deep inflammation

Melanoderma and alopecia in Yorkshire Terriers

• Probably genetic

• Usually affects dogs aged 6 months to 3 years

Skin tumours

• See under Neoplastic conditions

Drug reactions

Glucocorticoids

• Subcutaneous injections in this breed may cause local areas of alopecia

Endocrine conditions

Hyperadrenocorticism: pituitary-dependent (PDH)

• Possible breed predisposition

• Middle-aged/older

• 55-60% female

Gastrointestinal conditions

Lymphangiectasia and protein-losing enteropathy

• Possible breed predisposition

Hepatic lipidosis

• Breed predisposition

• Seen in puppies

Congenital portosystemic shunt

• Breed predisposition

• Onset of clinical signs < 1 year

Microvascular portal dysplasia

• Breed predisposition

Musculoskeletal conditions

Aseptic necrosis of the femoral head

• Also known as Legg-Calve-Perthe’s disease

• Mean age of onset: 7 months

• Aetiology unknown

Cartilaginous exostosis Congenital elbow luxation

• Type I and type II luxation seen in this breed

• Type I (90° rotation of proximal ulna) causes severe disability in this breed from birth or in first 3 months of life

• Type II (proximal radius displaced caudolaterally) usually presents at 4-5 months of age

Medial patellar luxation

• Significant hereditary component suspected

Odontoid process dysplasia

• Congenital

Delayed/non-union of fractures of the distal third of the radius and ulna in miniature and toy breeds

• May be associated with inadequate immobilisation

Neoplastic conditions

Keratoacanthoma

• Uncommon

• Possibly inherited

• Affects dogs of 5 years or younger

Pituitary tumour resulting in hyperadrenocorticism

• See under Endocrine conditions

Testicular neoplasia

• Believed to be a breed at increased risk

Neurological conditions

Hydrocephalus

• Congenital

• Relatively common

• Onset of signs: usually 4-5 months

Atlantoaxial subluxation

• Congenital

• Relatively common in this breed

• Age of clinical onset: < 1 year

Hemivertebrae

• Congenital

• Occasionally seen in this breed

Ocular conditions

Distichiasis

• Breed predisposition

Keratoconjunctivitis sicca

• Breed predisposition

Congenital keratoconjunctivitis sicca (lacrimal gland hypoplasia)

• Affected breed

Congenital, sub-epithelial, geographic corneal dystrophy

• Congenital condition; predisposed breed

• Occurs in young puppies (< 10 weeks); transient condition

Cataract

• Inheritance suspected

• Progressive cortical cataracts; may result in vision loss by 5 years

• Schedule 3 of the BVA/KC/ISDS Eye Scheme

Generalised progressive retinal atrophy

• Autosomal recessive inheritance suggested

• There may be two types: one presenting with night blindness at 4-8 months, the other at

6 years or later

• Schedule 3 of the BVA/KC/ISDS Eye Scheme

Renal and urinary conditions

Urate urolithiasis

• Higher incidence has been noted in this breed in some surveys

• Average age at diagnosis is 3-6 years

• Males may be predisposed

Calcium oxalate urolithiasis

• Higher incidence has been noted in this breed in some surveys

• Average age at diagnosis is 5-12 years

• Males may be predisposed

Struvite (magnesium ammonium phosphate) urolithiasis

• Higher incidence has been noted in this breed in some surveys

• Average age at diagnosis is 2-8 years

• Females seem to be predisposed

Calcium phosphate urolithiasis (hydroxyapatite and carbonate apatite)

• Higher incidence has been noted in this breed in some surveys

• Average age at diagnosis is 7-11 years

Calcium phosphate urolithiasis (brushite)

• Higher incidence has been noted in this breed in some surveys

• Average age at diagnosis is 7-11 years

• Males may be predisposed

Silica urolithiasis

• Higher incidence has been noted in this breed in some surveys

• Males seem to be predisposed

Reproductive conditions

Cryptorchidism

• Developmental defect believed to be inherited as a sex-limited, autosomal recessive trait

• Believed to be a breed at increased risk

Testicular neoplasia

• Believed to be a breed at increased risk

Respiratory conditions

Tracheal collapse

• Aetiology unknown

• Usually affects middle-aged to old dogs