Solidago species in grasslands of Paraguay and their relationship to hepatic photosensitivity in cattle

Abstract

Paraguayan livestock production uses forage grasses as a basic diet. Many species of weeds grow in these pastures, and some of them, like the Solidago genus, are toxic to the animals. This genus is reported to cause hepatic photosensitivity in cattle due to the toxic compound, saponins, contained mainly in the leaves. Saponins induce liver damage because they hamper the breakdown of photodynamic metabolites like phylloerythrin, formed from chlorophyll metabolism. Some species of Solidago are recognized in South America, but only two species are reported in Paraguay, and have been a cause of confusion in their identification and distribution due to the great morphological similarity they have. In the past, Solidago chilensis was the only species recorded in Paraguay and was related to causing hepatic photosensitivity in cattle. However, recent studies of the genus have demonstrated that Solidago microglossa is the dominant species of the genus Solidago in Paraguay, widely distributed across these grasslands. Therefore, the objective of this research is to define the dominant species of Solidago in Paraguay and as the primary cause behind photosensitive health disorders in cattle