Poisononous Plants for Ruminants in South America. Importance and Control Measures

Economic losses due to livestock poisoning by plants can be defined as direct and indirect. Direct losses are caused by death of animals, lower reproductive performance (abortions, infertility, and malformations), reduced production of surviving animals and other alterations due to transitory illness, sub clinical diseases with decreased production of milk, meat or wool, and increased susceptibility to other diseases due to suppressed immunological response. Indirect losses include cost of controlling poisonous plants in the pastures, management measures to prevent poisoning such as fencing and alternative grazing, reduction in the value of the forage due to delayed or deferred grazing, reduced land value, cost of replacement of the breeding stock lost by plant poisoning, and the cost associated with diagnosis and treatments of the affected animals. The economic loss by plant poisonings is difficult to estimate because reliable data are not available for many components of the cost, but losses due to deaths are easy to measure if there are data from diagnostic laboratories related with the frequency of different causes of death.