Evaluation of Myoglobin Determination for the Diagnosis of Tying-up Syndrome in Racehorses in Japan

In order to evaluate myoglobin (Mb) determination for the diagnosis of the typing-up syndrome, Mb concentration was estimated in serum and urine and the relationship between the Mb concentration and the severity of clinical symptoms was examined in 8 racehorses with myoglobinemia. The severity of clinical symptoms was graded by the temporary dis turbance of gait, since it was possible to grasp the severity of disease most objectively by this sign of all. The 8 racehorses were divided into three groups. One group was characterized by impossibility to walk, a second group by quasi-impossibility to walk, and a third group by stiffness of gait. Mb concentration ranged from 48 to 768 pg/ml in serum samples col lected first from these horses. In the first group, Mb concentration in the serum sample collected first after attack was higher than in any other group. In the third group, it was