Effects of cessation of supplemental feeding on mineral status of red deer Cervus elaphus and wild boar Sus scrofa in the Netherlands

From 1987 till 1997 we studied effects of cessation of supplementary feeding on performance of red deer Cervus elaphus Linnaeus, 1758 and wild boar Sus scrofa scrofa Linnaeus, 1758 in the Netherlands. We observed no changes in antler morphology, growth rate and body weight. Recruitment of red deer was unaffected and wild boar recruitment was determined by mast availability. The animals realised adequate dietary protein, energy (except for wild boar in poor mast winters), potassium, magnesium, copper, zinc, iron, and manganese levels from the natural diet. The natural diet of juveniles from both species was short in calcium, phosphorus, and sodium; adult red deer realised insufficient sodium intake. In red deer, bone calcium, phosphorus and total mineralisation declined. Potassium concentration in antlers, red deer and wild boar bone increased by a factor 2, 29, and 36 respectively. In both species bone sodium increased by a Factor 2. Concentrations of liver and kidney copper, iron and zinc were unaffected. Our findings suggest that red deer from this study, as a consequence of poor mineral availability, are in calcium and phosphorus stress, while both red deer and wild boar are in sodium stress. Future deficiencies may not be excluded.