Recent research comparing biomarkers in horses' blood with X rays showed these tests might be useful for predicting whether an animal is at risk of developing a bone or joint disorder, such as arthritis, said the study authors.
"If so, blood screening, which is easier than radiographic evaluation of large crowds of animals, would permit preselection," said Denis Verwilghen, DVM, MSc, DES, of the University of Liege in Belgium.
Because arthritis is a joint problem that mostly involves cartilage, X rays are not the best diagnostic tools--they can give indications about the condition of the cartilage, but by the time signs of bone changes are visible on an X ray, a lot of joint damage is already done.
"The best assessment of the joint surface can be obtained by examining it by arthroscopy (i.e. look with a camera into the joint)," he said, but the procedure is fairly invasive and not feasible on all horses. Ultrasonography can also aid in the evaluation of joint surfaces, but not all areas are accessible, and not all veterinarians perform ultrasounds.
One biomarker, a degradation fragment of type-2 collagen, one of the components of cartilage, increased in horses affected with arthritis but Verwilghen said he does not think a blood test will ever be the only means of diagnosing arthritis.
"Many blood markers, indicating cartilage degradation are available, but only indicate there is something going on in one of the many joints a horse has. Clinical signs and imaging techniques are the gold standard in the diagnosis of arthritis," he said.
Some diseases that develop at a young age, including some types of bony joint fragments and angular limb deviation, will increase the horse's risk of developing joint problems. Verwilghen suggested that screening be done as young as possible to anticipate problems.
The study "Relationship between biochemical markers and radiographic scores in the evaluation of the osteoarticular status of Warmblood stallions," was published in October in Research in Veterinary Science. The abstract is available on PubMed.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.