chapter  18
6 Pages

Rain Lily (Cooperia Pedunculata) Caused Photosensitization in Cattle and Deer in Texas

WithJ.L. Schuster, B.S. Rector, L.D. Rowe, E.M. Bailey, J.C. Reagor, S.L. Hatch

Photosensitization (PS) is the syndrome which develops when an animal which is hyperreactive to sunlight is exposed to the sun. This syndrome consists of dermatitis and/or conjunctivitis, and in some cases hyperesthesia, elicited only after exposure to light. Mycotoxins are suspected because of the environmental conditions characteristically present prior to outbreaks of PS. Treatment recommendations for the disease follow those for classical primary photosensitization. Affected animals should either be removed from rain lily-infested pastures, placed in a shaded area, and given dry feed, or moved to pastures where rain lily does not occur. The availability and phototoxic activity of dead leaf material of rain lily corresponds with outbreaks of photosensitization in cattle in DeWitt County during 1985 and 1986. Photosensitization of livestock and deer occurs during the time dead leafy material is available. Rain lily appears to be sought out by white-tailed deer, but cattle graze it only by chance or when overstocked.