Relationships between liver element concentrations and age in perinatal lambs dying of natural causes in Michigan, USA

A study was designed to characterize potential relationships between liver concentration of nine specific elements and age in preweaned Michigan lambs. All lambs that died before weaning in 1986 from 33 Michigan sheep producers were submitted to the Michigan State University Animal Health Diagnostic Laboratory for necropsy. Inductively coupled argon plasma emission spectroscopy was used to measure liver concentrations of Ca, Cu, Fe, K, Mg, Na, Na, P, and Zn in 888 lambs. Linear and non-linear regression techniques were employed to evaluate the relationship between liver element concentration and age. The potentially confounding variables farm of origin and cause of death were significant (P<0.01) in all models. No linear relationship was found between any liver element concentration and lamb age. Significant (P<0.05) non-linear relationships were found between liver concentrations of Cu, Fe, K, Na, Mg, and Zn and lamb age. Because of the large sample size of lambs selected from non-experimental populations, these results should provide diagnosticians with a useful guide for the interpretation of similar data when investigating perinatal lamb mortality.