野草地に放牧した牛の腎疾患を主徴とする中毒事故の発生状況について

抄録

In 1975, 39 young dairy cows were placed on an uncultivated grassland in Yamagata Prefecture for 5 days in August and 11 days in September. As a result, 29 cows died over a period from September 12 to October 2. They and severely affected cows manifested an increase in ascites, subcutaneous edema, low body temperature, abnormal cardiac function, low blood calcium level, high serum urea-nitrogen level, glycosuria, and aciduria. The dead cows presented an especially high urea-nitrogen level ranging from 186 to 281 mg/dl and indicating uremia induced by renal insufficiency. Histological changes were particularly remarkable in the kidney. In the uriniferous tubules, necrotic epithelial cells were shed and protein-like, hyaline, and crystalline substances present in the lumen. The amount of crystalline substance was much smaller than that reported in the case of oxalate poisoning. Hypoplasia of erythroblastic cells in the bone marrow was different from that observed in bracken poisoning. Such a bovine disease as affecting the kidney chiefly and exhibiting a high fatality was reported for the first time in Japan.