Staying up to date with common, let alone rare, health risks in susceptible dog breeds can be difficult. In this regular feature, our Educational Partner, the International Partnership for Dogs (IPFD), signposts resources on a particular breed and highlights breed-specific diseases
Meet the Shih Tzu – Update Your Knowledge!
Meet the Shih Tzu – Update Your Knowledge!
IPFD has published “Get a GRIHP! on Shih Tzu” as an in-depth examination of health and well-being of this breed.
The Shih Tzu originated in Tibet, where it has existed for centuries. The breed is one of the most ancient breeds in the world and hence having close genetic relationship to wolves. You’d never believe it, would you?
“Shih Tzus are excellent companion and family dogs of small size. The dogs are friendly, positive, and lively. They are adaptable and get on well with other dogs. The breed often reaches an old age.”1
The most important health risks in the breed are caused by brachycephalic and chondrodysplastic (short-limbed) conformation. Typical brachycephalic traits may cause eye, dental and breathing problems (BOAS). Nordic Kennel Clubs are listing the breed in the Breed Specific Instructions (BSI).2 Areas of risk are listed:
- Breathing: Problems caused by a too small head which limits the room of the upper respiratory cavities, too short muzzle and/or pinched nostrils. Standard reads; “Muzzle: Length about 2.5 cm from tip to stop.”*
- Eyes: Protruding eyes which dispose for injuries.
- Mouth: Narrow lower jaw and poor dentition.
The document advises to look for sound breathing and correct head proportions, eyes, jaws, and teeth.
Chondrodysplasia (CDPA – a retrogene in the chromosome 18) may be associated with excessively curved limb conformation causing carpal valgus, front limb rotation, elbow incongruity, and lateral radial head subluxation. These deformities may cause lameness and discomfort in affected dogs.
Some Shih Tzus are chondrodystrophic (CDDY – a retrogene in the chromosome 12). The CDDY allele frequency in the breed (UC Davis material3) is 0.25. This means that 25% of the alleles in the population studied were CDDY and 75% were normal. This is a risk allele for Intervertebral Disc Disease (IVDD).
According to Swedish insurance statistics, the most common problem area for which veterinary care is sought is eyes: corneal ulcers, corneal and scleral inflammation.1 Other key health conditions, mentioned by breeding organisations around the world include:
- Hereditary Cataract, Distichiasis, Macroblepharon and Entropion,
- Orthopedics – Patella Luxation, Legg-Perthes Disease, and Hip Dysplasia,
- Renal Dysplasia,
- Cardiac Disease, as well as
- Allergies and skin problems.
Vets should advise clients and prospective owners that brachycephalic conformation and small size mean that regular dental care is important. Some dogs may have excessively curved limbs which causes pain and discomfort and requires medication. Shih Tzus also require regular, extensive grooming.
To avoid health problems, dogs used for breeding should have straight legs, sufficiently long muzzle (the dividing line between the muzzle and the skull), and open nostrils. If possible, the CDDY gene variant should be avoided. “It is recommended that breeds with an allele frequency in the range of >0.25, <0.5) select away from this mutation over several generations and to mate dogs with CDDY to dogs with two copies of the normal allele to reduce the allele frequency without a dramatic effect on breed diversity.”3
Health strategies from various countries recommend or require screening to keep watch on conditions of interest:
References
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- Get a GRIHP on the Shih Tzu – https://dogwellnet.com/content/health-and-breeding/breeds/breed-specific-health-reports/get-a-grihp-on-the-shih-tzu-r811/
- Nordic Breed Specific Instructions – https://www.nkk.no/getfile.php/133181-1477564079/Dokumenter/RAS-dokument/BSI-BreedSpecificInstructions.pdf
- UC Davis Veterinary Genetics Laboratory: Managing the Genetics of Chondrodystrophy (CDDY) – https://vgl.ucdavis.edu/news/managing-genetics-chondrodystrophy
The International Partnership for Dogs (IPFD) is a non-profit working for dog health, well-being, and welfare. This article has been prepared by its Business and Project Coordinator, Katariina Mäki, PhD (Anim Sc)
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