Cantharidin Contamination of Alfalfa Hay

Abstract

Under laboratory conditions cantharidin was transferred from crushed blister beetles to filter paper. Twenty-one and 27% of the total available cantharidin was recovered from filter paper on which male and female Epicauta occidentalis Werner, respectively, had been crushed. Cantharidin was detected in samples of alfalfa hay infested with blister beetles when the hay was harvested from a field site. Thus, blister beetle–contaminated hay can be partitioned into cantharidin contributed directly by beetle parts and indirectly from cantharidin on the forage itself. Ingestion of crushed, dried beetles in the hay is a greater threat to livestock health than is contaminated hay free of blister beetles.