Date of this Version
Liver biopsies are used to assess trace element status of cattle for diagnostic and experimental purposes and generally provide better information than serum samples. Liver tissue collected at necropsy or slaughter is also used. The liver usually serves as the storage site for minerals. Serum concentrations may be maintained within adequate concentration ranges, at the sacrifice of liver mineral stores. If animals are receiving insufficient mineral, but have not yet depleted their liver stores enough to significantly lower the serum concentration, analysis of serum will be misleading. But analysis of liver biopsy samples may detect low liver trace element status.
Most published data used to establish the adequate liver mineral concentration ranges were collected from livers under experimental conditions at necropsy or slaughter. Few comparisons of trace element concentrations in liver biopsy and whole liver samples are available. There are no published mineral concentration ranges based upon liver biopsy samples. The objectives of this study were 1) to determine if trace element concentrations in the liver depended upon the liver section from which the sample was collected, 2) to compare the trace element content of pre-slaughter liver biopsy samples with post mortem trace element concentrations of the entire liver, 3) to determine if the magnitude of the concentration differences was sufficient to effect interpretation of nutritional status and 4) to determine if any gross affect was evident in livers from which previous biopsy samples had been collected.