Alsike Clover and Klein grass
Occasionally horses grazing clover, generally alsike clover (Trifolium hybridum), during wet or humid weather, develop a photosensitivity and hepatitis referred to as trifoliosis. A similar condition may also occur in horses or sheep grazing klein grass (Panicum coloratum) pastures during wet or humid weather. The toxin responsible for either trifoliosis or klein grass poisoning has not been identified, but the sporadic nature of the diseases and their occurrence only during wet humid weather suggest that mycotoxins, or plant metabolites produced under humid, high-moisture growth conditions, may be responsible.
Affected horses on clover pasture characteristically develop an acute photosensitization involving thinly haired and white-skinned areas, especially around the lips, nose, and feet. The condition has been referred to as ‘‘dew poisoning’’ because there is an association between the location of the dermatitis and contact with moisture present on the dew-laden clover pasture. Affected horses may exhibit icterus and other signs of liver disease. In such cases, there may be significant liver enlargement and evidence of liver degeneration. Horses generally recover rapidly from the photosensitivity if they are removed from the toxic pasture. Horses may graze the pasture again without problem under different growing conditions in subsequent years or after the pasture dries out.
|
|
