Dogs
Perhaps those more commonly affected are performance dogs e.g., dogs taking part in agility tests, racing or country sports. Wearing collars is a common factor in creating problems - intense pulling, getting the collar caught etc can cause misalignments of the neck vertebrae. If your dog is over-weight or unfit, he is also more likely to suffer from back problems, as his lack of muscle tone and skeletal frame will have the extra burden of weight to carry. Older dogs may suffer from arthritis for example, leading to gait abnormalities, which can eventually lead to a bad back. Dogs can also lie on bedding, which doesn't provide them with enough support whilst sleeping.  

Cats
Cats have very flexible spines and can jump and climb effectively. Like dogs, some cats wear collars, which, if getting caught up in fencing etc, can cause injuries. Getting involved in frequent fights can cause injury. The most common cause of structural/neurological problems is a vehicle accident. Also obesity, stress, illness and old age are other examples, which may lead to back and joint problems.

How do I know if my animal has a back problem?

Animals can regularly exhibit the following behaviours or problems as a result of experiencing back pain:  

Dogs & Cats

Limping or lameness.  

Not wishing to evenly distribute weight on all 4 limbs.  

Difficulty jumping/getting up or down.  

Difficulty climbing (Cats).  

Not being able to run fast.  

Displaying signs of aggression, pain, reluctance to play or unhappiness.

Lack of performance (dogs - agility training, greyhound racing etc).