ATYPICAL MYOGLOBINURIA IN GRAZING HORSES

In autumn 1995 for the first time horses were taken to the clinic for horses in Hannover that showed symptoms of a muscular disease. not see n so far. None of the twelve patients survived this atypical myoglobin uria although extensive treatment was performed. At the same time othe r veterinarians reported on 103 cases. 99 of them died. Without except ion all horses and ponies were not in training and kept on pasture jus t before the disease set on. In most of the cases more than one horse of a single pasture was affected. Different breeds, sexes and age grou ps were concerned. In the beginning all horses showed muscular tremor, stiffness and stagger. They were dull or apathetic. Heart rates and b reathing frequencies were elevated. Appetite was maintained very long and only a few horses were painful. The rectal palpation revealed only a highly filled bladder. All patients showed a massive elevation of c reatine kinase and myoglobinuria was characteristic. Treatment include d infusion of isotonic solutions, analgesics, anti-inflammatory agents and doses of Vitamin E/selenium. Despite intensive medical care and t reatment all horses came to recumbency within three days and finally d ied. In pathologic-anatomical examinations various muscle groups showe d a marked, acute rhabdomyolysis of type I fibres. Up to this day labo ratory diagnostics, clinical, pathologic-anatomical, histological and toxicological findings could not reveal the etiology of atypical myogl obinuria.