Horse News & Views - September 2002

Ministry of Agriculture, Food and Rural Affairs

Ontario Association of Equine Practitioners

• Tying-up syndrome or exertional rhabdomyolysis is a painful myopathy (condition of the muscle) associated with exercise. It has been described in many breeds. Several risk factors are reported to predispose to the syndrome, including: exercise preceded by a day or more of rest, feeding high levels of carbohydrates, lameness, nervous temperament, being young and female, a viral infection and the time of year (winter being highest but may be related to management factors rather than environmental conditions). Studies indicate that the syndrome affected 4.9% of thoroughbred racehorses in Minnesota and 7% of polo horses. Twenty-five cases in polo horses were associated with horses performing more work than they were used to. Thoroughbreds fed more than 4.5 kg of grain per day were more likely to suffer from the condition. (McGowan et al. Veterinary Record 2002; 150 (17): 535-537)
• A quarter horse in southwestern Ontario has tested positive for Eastern Equine Encephalitis (EEE). This is the fourth year since 1992 that EEE has been diagnosed in horses in Ontario. In the fall of 2001, two horses with clinical signs were confirmed as infected. One was a resident horse of the South Muskoka area. The other had been in competition in the same area, as well as many other locations throughout Ontario.

   

• Equine Research Centre, University of Guelph