Screening β-agonist residues in cattle, pig and horse liver

Residues of beta-agonists were assayed in liver samples from 102 animals (38 cattle, 29 pigs and 35 horses) using an ELISA technique. A higher percentage of samples tested positive than what is reported in the Italian National Residue Control Plan carried out in 1995 and 1996. These results indicate that animals could have been treated with therapeutic doses without respecting the appropriate withdrawal times or with illegal growth-promoting doses. This work includes horse species for the first time. It is recommended, therefore, that beta-agonist residue testing should also be carried out on horses for slaughter, and that a European Union agreement on withdrawal times should be reached, perhaps differentiating times according to species.