title: Experimentally induced photosensitization in cattle with Cooperia pedunculata.
abstract: Photosensitization was induced in 2 Charolais heifers following administration of a mixture of air-dried, ground, green (75%) and dead (25%) leaves of the south Texas forb, Cooperia pedunculata, and subsequent exposure to sunlight. Plant material used in this study was collected from a pasture where natural cases of primary bovine photosensitization were occurring. Signs of photosensitization were observed in one heifer after 2 doses of plant material--10 g/kg on day 1 and 5 g/kg on day 2. Continued administration of plant material at 5 g/kg/d on days 3, 4, 7, 8, and 9 resulted in severe signs and lesions of photosensitization and death on day 23. A second heifer developed signs of mild photosensitization following administration of plant material at 1.7 g/kg/d for 4 days. This heifer recovered by day 18. Clinical and pathologic findings of this trial were consistent with the primary form of photosensitization observed in natural cases seen in cattle of south Texas exposed to this plant.
authors: Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station 77843-4466.
authors: S W
authors: SW
authors: Casteel
authors: L D
authors: LD
authors: Rowe
authors: E M
authors: EM
authors: Bailey
authors: R A
authors: RA
authors: Fiske
authors: C W
authors: CW
authors: Bridges
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000209:etiology* / Q000473:pathology; D005260:Female; D010787:Photosensitivity Disorders / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D010947:Plants, Toxic; D012867:Skin / Q000473:pathology; D014887:Weather