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The Center for Native Grasslands Management

Title: Photosensitization in meat goat kids grazing Alamo switchgrass
Year: 2002
Author(s): Elmore, S. A., Lee, S. T., Anderson, K. L., Luginbuhl, J. M., Brown, T. T., Cullen, J. M.
Source Title: Proceedings of the Third Eastern Native Grass Symposium
Source Type: Proceedings
pages: 311
Original Publication:  
Abstract: The purpose of the study was to elucidate the cause of clinical photo-sensitization, elevated liver and kidney specific serum enzymes, and histologically evident hepatopathy observed in a herd of 3 to 5 month-old Boer cross goats grazing Alamo switchgrass during the summer of 2001. Twenty-four (30%) out of 81 goats subsequently developed clinical signs of lethargy, poor body condition, and skin ulcerations. Six affected goats were euthanized and presented for necropsy. Necropsies revealed hepatocellular necrosis, Kupffer cell hypertrophy and hyperplasia, biliary hyperplasia, and fibrosis, and mild cholangitis. Birefringent crystals were present in the bile ducts and Kupffer cells. Hepatic lesion severity appeared to correlate with increased switchgrass exposure time. Renal lesions included proximal tubule dilation with evidence of necrosis admixed with various stages of degeneration and regeneration in the medullary region. Erosive to ulcerative skin lesions, supportive of photosensitization, were complicated by parapoxviral dermatitis, dematophillosis, and mixed bacterial colonization. Serum chemistry abnormalities include BUN, total bilirubin, AST, and decreased values for albumin, cholesterol, and triglycerides. Gas chromatography-mass spectrometry indicated that diosgenin was the major steroidal sapinogen in the switchgrass grazed by the affected goats. This study suggests that the diosgenin present in the switchgrass sample was both hepatoxic and nephrotoxic to young goats.
Publisher: The North Carolina Botanical Garden, Chapel Hill, NC, October 1-3, 2002. Omnipress, Madison, WI
Editor(s): J. Randall