Certain birth defects in livestock induced by poisonous plants possess clinical similarities to congenital deformities in humans. They meet some criteria as models for those corresponding human conditions. They are induced by several plants, including members of the Astragalus, Lupinus, Conium, Nicotiana and Veratrum genera. The terata expressions include effects in bone and soft tissue, particularly in the limbs, spinal cord and cephalic regions. Whether these livestock conditions become extensively used as models of human terata will be determined by how well they meet the criteria sought in good models. These prospective models have many favorable characteristics; however, being large domestic livestock, they have certain logistic disadvantages compared with small rodents as models.