Health Testing

Health testing is important for any breeding program; however, the limitations of the tests must be understood.  Many health issues don’t become evident until maturity, and for that reason it is not recommended to undertake screening health testing until over 12 months of age.  This is why we don’t recommend breeding with any animal under 12 months of age.  Obviously if a major health issue is evident under 12 months of age, i.e. the animal is clinically affected, that animal should be excluded from the breeding program.

Respiratory Function Grading Scheme

The Respiratory Function Grading (RFG) scheme is essentially an exercise tolerance test for brachycephalic breeds of dog.  Brachycephalic Airway Obstructive Syndrome (BOAS) is a disease of the upper respiratory tract of brachycephalic breeds of dog.  There are surgical procedures available to treat BOAS, however the surgery is risky (up to 25% of animals undergoing surgery will die from the surgery) and often the problem is unable to be fixed.  Traditionally BOAS has been believed to be caused by several issues in a multitude of combinations: elongated soft palate, everted laryngeal saccules, hypoplastic (small) trachea (airway), stenotic nares and enlarged tonsils.  More recently contrast tomography (CT) images of the skulls of brachycephalic dogs have shown that most affected dogs have excessive tissue in their noses obstructing airflow and/or laryngeal collapse.  Whilst we can cut some of the affected excessive nose tissue out, most of it will remain.  We cannot fix laryngeal collapse.  For this reason, we believe functional testing will be a better assessment for screening breeding dogs than taking radiographic or CT images and trying to exclude animals with short noses from breeding.  For many years screening programs have focussed on imaging techniques, and while it is still recommended, it makes sense that we would achieve more rapid advancement in improving these animals’ welfare by selecting for animals that can function well.

Some argue that the problem is too short noses and breeders should select for longer noses.  However, this does not explain why other short nosed (brachycephalic) breeds such as Boston Terriers and Brussels Griffons do not appear to be affected by BOAS.

Certainly, more research is required in this area, however the RFG scheme appears to currently have the best merits for improving the welfare of these brachycephalic breeds.  Currently scoring is done for French Bulldogs, Bulldogs and Pugs.  The dogs are exercised at 6 km/hr for 3 minutes and scored according to their lung sounds.  A dog with no sounds is scored a 0 and a dog which is very loud and/or unable to exercise is a 3.  The nares are also assessed to contribute to the score.  Currently Grade 3 dogs are recommended to be removed from the gene pool and are classified as failed.

Hip and Elbow Dysplasia

Breeds prone to hip and elbow dysplasia should have their hips and elbows radiographed under general anaesthesia over 12 months of age, with the radiographs scored by a specialist veterinary radiologist.  It is recommended not to breed with a dog with more than ½ of the breed average score in any one hip.  With regards to the elbows the recommendations change dependant on the breed and what is seen. 

There is a special type of hip radiograph called PennHip radiographs.  These look specifically at the looseness or laxity in the hip joint and give a probability for the development of hip dysplasia.  Whilst being more sensitive than standard hip and elbow radiographs, until breed clubs all start to recommend this system it will not commonly be done.  The two different systems for hip screening are not able to be compared.  PennHip should never be used to assess if a dog needs hip surgery, it is imperative this is based on the clinical signs of the dog.  There are no good ‘hip dysplasia preventative surgeries’, so screening dogs for risk of hip dysplasia which are asymptomatic is unwarranted.

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