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Blood lead (Pb) is used to diagnose Pb poisoning and exposure in cattle, but there are limited data comparing circulating Pb with concentrations in beef from the same cattle. This study determines whether there is a correlation between blood Pb and tissue Pb concentrations in accidentally exposed cattle. Pb analyses were carried out on ante-mortem blood and post-mortem tissues (including, if available, brain, liver, skeletal muscle, bone, gastrointestinal contents and kidney, and also foetal tissues from one cow) collected from 13 cattle known to have accidental Pb exposure and from three control cows with no known exposure. Variables from cattle were analysed statistically using a Shapiro-Wilk normality test and non-parametric descriptive and association statistics. Blood Pb from exposed cattle rank-correlated with liver, bone and kidney Pb concentrations, but not with the Pb concentrations of brain, skeletal muscle or gastrointestinal contents. The lowest blood Pb concentration associated with a detectable skeletal muscle Pb concentration (> 0.1 mg kg - 1 dry matter) was 4.57 μg dl -1 . Based on these findings, we recommend that cattle with blood Pb > 2.5 μg dl -1 be withheld from slaughter and that liver, bone and kidney from all cattle with known Pb exposure be withheld from the human food chain.

The current study compared the LeadCare(R) II test kit system with graphite-furnace atomic absorption spectrometry for blood lead (Pb) analysis in 56 cattle accidentally exposed to Pb in the field. Blood Pb concentrations were determined by LeadCare II within 4 hr of collection and after 72 hr of refrigeration. Blood Pb concentrations were determined by atomic absorption spectrometry, and samples that were coagulated (n = 12) were homogenized before analysis. There was strong rank correlation (R(2) = 0.96) between atomic absorption and LeadCare II (within 4 hr of collection), and a conversion formula was determined for values within the observed range (3-91 mcg/dl, although few had values >40 mcg/dl). Median and mean blood pb concentrations for atomic absorption were 7.7 and 15.9 mcg/dl, respectively; for LeadCare II, medians were 5.2 mcg/dl at 4 hr and 4.9 mcg/dl at 72 hr, and means were 12.4 and 11.7, respectively. LeadCare II results at 4 hr strongly correlated with 72 hr results (R(2) = 0.96), but results at 72 hr were lower (P < 0.01). There was no significant difference between coagulated and uncoagulated samples run by atomic absorption. Although there have been several articles that compared LeadCare with other analytical techniques, all were for the original system, not LeadCare II. The present study indicated that LeadCare II results correlated well with atomic absorption over a wide range of blood Pb concentrations and that refrigerating samples for up to 72 hr before LeadCare II analysis was acceptable for clinical purposes.