Comparison of maternal blood and fetal liver selenium concentrations in cattle in California

Abstract

SUMMARY Selenium concentration was measured in paired maternal blood samples and fetal liver specimens collected at a San Joaquin County, Calif, slaughterhouse (beef = 19, dairy = 54) and from bovine aborted fetuses submitted to the California Veterinary Diagnostic Laboratory System (CVDLS; beef = 20, dairy = 20). Of the slaughterhouse samples and specimens, dairy maternal blood selenium concentration was significantly (P < 0.001) higher (mean ± sd; 0.22 ± 0.056 µg/ml) than that for beef breeds (0.137 ± 0.082 µg/ml). The CVDLS mean maternal blood selenium concentration for the dairy-breed samples (0.192 ± 0.028 µg/ml) was similar to that for the slaughterhouse dairy-breed samples, but was greater than that for the slaughterhouse beef-breed samples. Slaughterhouse mean fetal liver selenium content also was higher (P < 0.001) for the dairy breeds (0.777 ± 0.408 µg/g), compared with the beef breeds (0.443 ± 0.038 µg/g). Mean fetal liver selenium content for slaughterhouse specimens was higher (P < 0.002) than that for the CVDLS specimens (beef, 0.244 ± 0.149 µg/g; dairy, 0.390 ± 0.165 µg/g). At the CVDLS, dairy fetal liver content was greater (P < 0.001) than that for beef breeds. Mean ratio of fetal liver selenium content to maternal blood selenium concentration was 3.53 ± 1.89 for dairy breeds at the slaughterhouse (liver-to-blood correlation [r] = 0.38), and was 2.11 ± 1.00 for dairy breeds at the CVDLS (r = 0.31) and 3.43 ± 1.50 for beef breeds (r = 0.58). Both slaughterhouse breed ratios were significantly (P < 0.002) greater than the CVDLS dairy-breed ratio. On the basis of these results, breed and source location should be taken into account when interpreting selenium values. Fetal liver selenium content should only be used as a screening test and combined with whole blood selenium concentration from clinically normal herdmates to evaluate herd selenium status.