Hairy vetch (Vicia villosa) toxicosis in a purebred Angus herd

Abstract

Four mature, purebred Angus cattle from a herd of 460 are presented at the Texas Veterinary Medical Center at Texas A and M University, Texas, USA with a history of weight loss and alopecia that began one to seven days prior to examination. Five unexplained deaths of other members of this group, within the same pasture, had occurred on the ranch during the previous two weeks. Clinical findings common to all four animals were skin lesions that ranged from mild alopecia with moderate hyperkeratosis, severe folding and thickening of the skin with excoriation and edema. Lesions were distributed bilaterally on the face, neck, topline, perineum, distal limbs, udder and thorax. Increased salivation, clear ocular discharge and lymphadenopathy were also observed in all four animals. Skin biopsy, histopathological examination, serum biochemical findings and hematology results were consistent with hairy vetch (Vicia villosa) poisoning. Cattle were removed from this pasture and the other affected animals were isolated for observation and supplemental feeding.