Selenium status in cattle at slaughter:: Analyses of blood, skeletal muscle, and liver

The objective of the study was to assess relationships among selenium concentrations in the blood, and liver and diaphragmatic muscle tissues and the activity of glutathione peroxidase (GSH-Px) in whole blood and to decide on the use of these biochemical values in the diagnostics of selenium deficiency in cattle. Samples were collected from 44 cattle at slaughter. Regression and correlation analyses yielded equations of regression lines and correlation coefficients (r) documenting significant (p < 0.01) relationships between whole blood selenium concentration on the one hand and all the other biochemical parameters under study on the other band. The relations were expressed by the following equations and correlation coefficients: blood Se vs. liver tissue Se y = 1.20x + 31.58, r = 0.78; blood Se vs. muscular tissue Se y = 0.53x + 11.97, r = 83; blood Se vs. GSH-Px y = 8.29x - 68.77, r = 0.93. The equations were used to calculate selenium concentrations in hepatic and muscular tissues and GSH-Px activity corresponding to whole blood selenium concentration of 100 mug.l(-1) and critical concentrations indicating selenium deficiency (calculated value - 10%). Poor selenium status, as assessed from blood, muscle and liver selenium concentrations, was found in 80%, 70% and 73% of the tested animals, respectively. Considering these results and the rather uniform within-herd distribution of the values we can conclude that tissue analyses are suitable for the assessment of selenium status particularly in feeder bulls and grazed beef cattle in which only minor individual differences in selenium supply can be expected.