The epidemiology and economics of pooled testing for disease investigations of lead exposure involving beef cattle in Saskatchewan (2007-2019).

From 2007 to 2019, the Western College of Veterinary Medicine Disease Investigation Unit conducted lead investigations in 12 beef cow-calf herds and tested 1104 presumed exposed but clinically unaffected cattle, 49 of which were unsafe for slaughter (blood lead ≥ 0.1 ppm). In all investigations, the lead source should be evaluated, and all potentially exposed animals intended for food should be tested. Clinically affected animals should be tested individually. Individual testing of clinically unaffected animals may be expensive for large groups. However, pooling a conservative number of blood samples (n = 2 to 5) from clinically unaffected cattle may efficiently identify groups that are safe for slaughter. If a pooled test produces a blood lead concentration over the minimum threshold (0.1 ppm/n), these samples should be individually re-tested. Herd size, lead toxicity prevalence, pool size, and number of pools that require individual re-testing all affect the potential cost savings of pooled testing. Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.