Chemical and biochemical aspects of photosensitization in livestock and poultry.

Certain synthetic and naturally occurring chemicals, particularly those found in some range plants, may interact with livestock and poultry in the presence of activating light to produce photosensitization. Such photosensitization may have serious implications for livestock producers as a result of causing reduced performance of and even death of affected animals. The mechanisms producing photosensitization in livestock and poultry are discussed in context with the chemical nature of major livestock photosensitizers. The possibility that photosensitizing agents for livestock may have toxicologic significance in humans consuming photoactive residues in meat or animal byproducts is considered.