Enzootic calcinosis caused by Nierembergia rivularis in sheep.

Enzootic calcinosis was diagnosed in sheep in Uruguay in pastures containing the plant Nierembergia rivularis. In a flock of 200 sheep, 20 were affected and 12 died. Clinical signs were anorexia, weight loss followed by cachexia, stiffness, and kyphosis. At necropsy and histologic examination, mineral deposits were observed on the medial layer of the arteries, heart, lungs, and kidneys. Similar lesions were also observed in 3 sheep forced to graze in an area containing the plant, while no lesions were observed in a control sheep that grazed in an area free of N. rivularis. It is concluded that N. rivularis is a calcinogenic plant for sheep.