Tying-Up in Standardbred Horses

A study of Standardbreds in Sweden showed that about 6.4% of studied horses had a history of tying-up. This is comparable to an incidence of about 6% in Thoroughbreds, not surprising when their similar genetic pattern is taken into account. As in Thoroughbreds, the incidence was highest in mares with nervous temperaments. Affected Standardbreds in this study also had faster lap times and a higher winning percentage than their unaffected peers.

Some studies in Thoroughbreds with tying-up suggest that affected horses have muscle fibers that contract and relax more quickly than normal, possibly allowing them to run faster but also predisposing these horses to tying-up.