Preliminary study of ivermectin residues in bovine livers in the Bogota Savanna

The present study tended to determine the ivermectin residues in cattle livers using the competitive ELISA technique and correlate gender and age variables with residual presence. Also, it was described the histopathological findings in analyzed samples. A total of 90 livers of randomly selected cattle were sampled in a type II slaughterhouse located in the Bogota Savanna. The samples were analyzed for ivermectin residues using the competitive ELISA technique and a histopathological evaluation was performed using the H&E technique. Only the 22 % (20/90) of the analyzed samples presented ivermectin residues. Of the positive individuals, the majority came from Cogua 35 % (7/20), Zipaquira 30 % (6/20) and Sopo 20 % (4/20). The breeds with residues presence corresponded to Half-Blood 35 % (7/20), Zebu 25 % (5/20), Normande 20 % (4/20) and Jersey x Holstein 15 % (3/20). Eighty five, 85 % (17/20) of the individuals were older than 1.5 yr. In regard to the gender variable, the majority of animals were males 65 % (13/20). Of the evaluated animals 3 % (3/90) exceeded the maximum residue limit (> 100 ppb). No association was found between the presence of residues and the gender and age variables (P>0.05). The majority of histopathological changes were mild or moderate, with alterations in architecture and inflammatory changes standing out. It was found association between the presence of residue and variables microcirculatory alteration, inflammatory alteration and changes similar to the cell death (P<0.05). As a conclusion, the competitive ELISA test used in this study served as a screening method for the detection ivermectin residues in the analyzed samples.