Haggard D L, Whitehair C K, Langham R F
J Am Vet Med Assoc. 1978 Feb 15;172(4):495-7.
Sudden death losses occurred in 4-month-old beef calves with clinical signs of muscular dysfunction, including tetanic spasms. Gross lesions were not diagnostic. Microscopic lesions consisted of deposition of calcium salts in the elastic fibers of the arteries in the heart, lungs, and spleen and in the trabeculae of the spleen. Focal areas of interstitial nephritis were characterized by infiltration of lymphocytes and plasma cells. Samples of hay and silage that the cattle were consuming were low in magnesium. Calves with spasms responded to magnesium salts given intravenously, and losses ceased after a magnesium-containing supplement was fed free choice to the calves and cows.
4月龄肉牛犊出现猝死，伴有肌肉功能障碍的临床症状，包括强直性痉挛。大体病变无诊断价值。显微镜下病变表现为钙盐沉积于心脏、肺和脾脏动脉的弹性纤维以及脾脏小梁中。局灶性间质性肾炎的特征为淋巴细胞和浆细胞浸润。牛所食用的干草和青贮饲料样本中镁含量低。有痉挛症状的犊牛对静脉注射镁盐有反应，在给犊牛和母牛自由采食含镁补充剂后死亡停止。
