Abstract
The present work aimed to determine the percentage of bovines that tested positive for clenbuterol hydrochloride (CCL), based on urine samples of cattle slaughtered in 3 slaughterhouses of the State of Mexico. To the effect, samples were collected in the municipal slaughterhouses of Toluca (59), Ixtlahuaca (52), and Atlacomulco (40), resulting in a total of 151 samples. Sample analysis was carried out using the ELISA test, and descriptive statistics were used to report the results. 105 of the analyzed samples were positive (69.53%); by slaughterhouse, positivity was 48, 30, and 27, respectively. When establishing different ranges of CCL concentration, 46 samples were in the range of 200 to 1999 pg g-1; 6 samples were in the range of 2000 to 3525 pg g-1; 3 were in the range of 3526 to 5050 pg g-1; 1 sample was between 5051 and 6575 pg g-1, and 95 samples were between 6575 and >8100 pg g-1. The slaughterhouse with the highest percentage of positivity was that of Toluca, based on the established ranges, and the highest concentrations were also observed there. The minimum limit for the detection of CCL (2000 pg g-1) allows considering that, based on both concentration and kinetics, the quantities detected in the study serve as an important indicator of residuality in this type of sample