Not only can exercise safely be imposed in any age horse, but it also might be protective to joints, reported a Colorado State University research team led by Chris Kawcak, DVM, PhD, Dipl. ACVS, an associate professor and equine surgeon.

"Injuries involving the musculoskeletal system in horses are common and can typically result in secondary to chronic changes in the structure of bone and cartilage," said Kawcak.

Previous studies have demonstrated that musculoskeletal strength can be improved by exercising at an early age in a number of species and that this technique could even decrease the incidence of injuries later in life. To date, however, little data exist concerning either the optimum level at which strength can be maximized or upper and lower limits for joint loading to prevent damaging horses' joints.

To determine the effects of exercise in young horses on the tissues of the metacarpophalangeal (fetlock) joint, Kawcak and colleagues performed computed tomography (CT) and examined articular cartilage metabolism and the microscopic structure of the joint tissues in 12 horses. Six of the horses were maintained on pasture, whereas the remaining six horses had additional exercise from 3 weeks of age to 18 months.

Key findings of the study were:

  • Exercised horses had fewer gross lesions of the examined joint tissues (e.g., roughened articular cartilage surface, osteochondritis dissecans, cartilage fragments);

  • Horses in the exercise group had greater bone volume and a higher bone formation rate than the non-exercised horses; and,

  • Less articular cartilage staining (indicative of mil