The ingestion of pods of Prosopis juliflora causes nervous signs in cattle due to lesions in the trigeminal nuclei, and colics in horses due to the formation of phytobezoars in the gut. The objective of this research was to study the toxicity for of P. juliflora pods in horses, and to establish if 30% of pods in the feed are not toxic for cattle. Three experiments were performed. In Experiment 1, two steers were fed, during one year, with food containing 30% of P. juliflora pods. None of the experimental animals showed nervous signs. In Experiment 2, two horses received pods of P. juliflora in amount equivalent to 1% of their bw during four months. For other 3 months this amount was increased to 1.5% bw. In Experiment 3, two horses received P. juliflora pods ad libitum during 30 days. None of the horses showed nervous signs or colic due to the presence of phytobezoars in the gut. These results suggest that P. juliflora pods, despite their toxicity, can be used to feed cattle at concentrations of 30% of the food during one year. There are no restrictions for the use of P. juliflora pods in horses in confined or semi-confined systems, but it is not recommended to maintain equidae grazing in areas where P. juliflora is fructificating. It is suggested that there is a loss in the capacity of the pods to form phytobezoars after harvesting. Cattle may be kept in areas invaded by P. juliflora, during fructification, for no more than 30 days.
Prosopis juliflora; toxicity; nervous signs; phytobezoars; cattle; equidae