Limb deformities in foals associated with ingestion of locoweed by mares.

Five of 26 pregnant mares observed ingesting locoweed (Astragalus mollisimus) subsequently aborted and another 10 produced foals with various limb deformities. Seven of the foals had deformities of a flexion-extension type and 3 had angular deformities. Four foals were normal. The limb deformities either resolved spontaneously (5 cases) or were treated successfully (in 4 of the other 5 cases). The problems of abortion and limb deformities were attributed to locoweed ingestion on the basis of the mares having eaten the plants, and the similarity of the syndrome to that previously reported in sheep and cattle.