Concentrations of trace elements in the hair of different colours and different sampling locations in veal calves

The aim of this study was to investigate whether hair can be used as a non-invasive sample material that is less influenced by homeostasis than blood. Blood analysis is an invasive method of assessing trace element status, concentrations can be influenced by homeostasis, and they might not accurately reflect the true status of the animal. Thus, hair samples could play an important non-invasive role in diagnosing chronic deficiencies. The study group included 100 veal calves of a variety of different breeds and crossbreeds aged between 2 and 5 months, consisting of both sexes. Samples were taken to compare different locations and colours of hair. The concentration of trace elements Mn, Fe, Se, Co, Cu, Zn and Mo of different coloured ear and shoulder hair (black, brown and white) were measured, and concentrations were compared with those in the liver, kidney, muscle and blood plasma. All samples were measured with triple-quadrupole collision/reaction cell ICP-MS. This study showed that both hair colour and hair location have an influence on trace element concentration. In this animal series, no strong correlations could be found between trace element concentrations in hair and other tissues, suggesting that such an approach is only feasible when a heterogeneous animal series is used. Whether hair is a feasible sample material for trace element analysis cannot be conclusively answered; a larger sample size and further studies on other influencing factors would have been required. In addition, the procedure would need to be highly standardized, as both sampling localization and hair colour appear to have an influence.