Development of a simple enzyme immunoassay for blood haptoglobin concentration in cattle and its application in improving food safety

Abstract

Abstract Objective To verify the role of haptoglobin, a major acute-phase reactant protein in cattle, as a marker to identify health/disease status in cattle and further assess its potential in improving food safety. Sample Population Serum samples from various cattle groups: clinically normal cattle comprising steers (n = 157) and culled dairy cows (n = 92) before death (antemortem [AM]); retained carcasses (n = 57) railed off the line during postmortem (PM) inspection; and apparently AM normal culled dairy cows (n = 57). Procedure -Efficacy of the simplified monoclonal antibody-based enzyme immunoassay was established by comparing results of haptoglobin tests performed independently on aliquots of serum samples by 3 laboratories. Results Haptoglobin concentration was significantly ( P ≤ 0.0001) different between the PM retained carcass group (n = 57) and the AM steer (n = 157) and culled dairy cow (n = 92) groups. In addition, haptoglobin concentration in AM steers (n = 157) and culled dairy cows (n = 92) was significantly ( P < 0.0012) different, possibly reflecting a higher percentage of underlying pathologic or inflammatory conditions in animals of the latter group. Evaluation in 3 laboratories of sera from a group of culled dairy cows (n = 57), each laboratory performing a different test procedure, indicated that correlation of haptoglobin concentrations was good between the reported test procedure and the unmodified test and the classical hemoglobin-binding assay that measures peroxidase activity. Conclusion Haptoglobin determination is effective in identifying diseased and healthy cattle. It may be a potentially important tool for application at the farm and slaughterhouse as an aid in improving food safety. ( Am J Vet Res 1998;59:1101-1107)