Breed Club Hemivertebrae Testing Explained

Hemivertebrae is a congenital vertebral malformation that causes the distinctive corkscrew tail seen in certain dog breeds, especially the pug. This condition arises from abnormal spinal vertebrae development, where parts of the spine fuse or twist instead of forming normally. While a curled tail itself may not cause issues, the spinal deformity can sometimes compress the spinal cord or nerves, potentially causing pain or neurological problems affecting mobility.

Common in smaller brachycephalic breeds with curled tails, such as the French bulldog and English bulldog, hemivertebrae varies in severity. In many dogs, it causes no symptoms besides the curled tail, but more severe cases can lead to symptoms including hind limb weakness, incontinence, and discomfort, usually emerging as puppies grow and become mobile.

Why Breed Clubs Recommend Hemivertebrae Testing

Because hemivertebrae is hereditary, breed clubs for affected breeds actively promote pre-breeding screening. The goal is to identify dogs with severe or problematic spinal deformities and prevent them from passing these on, thereby improving the overall health and welfare of future generations.

The pug breed club particularly recommends testing all potential breeding dogs. Adult dogs without mobility issues usually do not require testing unless intended for breeding.

How Is Hemivertebrae Testing Done?

Testing involves radiographic X-rays of the dog's spine to detect any vertebral abnormalities. Unlike simple DNA tests, radiographic imaging can reveal the physical spinal deformities causing hemivertebrae.

Because multiple angles and clear images are required, dogs generally need to be anaesthetised during the procedure. This ensures the dog remains still and reduces risks, especially important for brachycephalic breeds that can be sensitive to sedation.

The X-rays are then assessed by a veterinary radiographer to determine the presence and degree of spinal twisting or fusion. Even if the dog shows some spinal deformity but remains asymptomatic, it is advised not to breed from these dogs because the condition may still be inherited by their offspring.

Understanding Test Results and Breeding Decisions

Test results typically include grading the degree of hemivertebrae, with higher grades indicating more severe spinal malformation. Responsible breeders avoid using dogs with moderate to severe deformities for breeding to reduce the occurrence of health problems in puppies.

Breeding decisions are made in conjunction with breed clubs and veterinary advice to balance preserving the breed’s standard while minimising health risks associated with hemivertebrae.

Which Dog Breeds Are Most Affected?

Hemivertebrae is most common in brachycephalic breeds with curled tails, including:

• Pugs
• French bulldogs
• English bulldogs
• Other small curled-tail breeds

Rarely, it has been documented in other breeds like certain German Shepherd lines, but these cases are less frequent.

Should My Dog Be Tested?

If you have a brachycephalic dog breed with a curled tail and plan to breed, testing is strongly recommended to safeguard puppy health. For pet owners whose dogs show no mobility issues, routine testing may not be necessary but consult your vet if any neurological or movement problems develop.

Summary and Responsible Ownership

Hemivertebrae testing is an important health screening recommended by breed clubs to ensure responsible breeding practices. By understanding and using this testing, breeders can help reduce the prevalence of painful spinal deformities in predisposed breeds.

Always seek veterinary advice and work with reputable breeders who prioritise health screenings and breed welfare. Responsible pet ownership includes awareness of hereditary conditions like hemivertebrae and making informed choices to promote the wellbeing of every dog.