Iron in cattle health

Iron is one of the most abundant elements on Earth, a vital component of every living organism, and an essential micronutrient for all animal species. The primary source of iron for calves and other new-born ruminants is milk or a milk replacer, while for adults it is forage. Drinking water can contain various amounts of Fe ions and can be a source of this element as well. Systemic iron homeostasis in vertebrates is mostly regulated by hepcidin (HEP), a peptide synthesized and secreted by hepatocytes. The largest amounts of iron in the body are incorporated into proteins, mainly haemoglobin and myoglobin. This element participates in several biochemical processes including blood production, transport of oxygen, energy metabolism and immune processes. Iron deficiency can result in so-called iron deficiency anaemia, mostly occurring in young calves due to low iron content in cow’s milk and high demand for this element by calf’s organism. Iron poisoning mostly occurs due to excess iron intake caused by an inappropriate dose of iron given to animals (injection or per os administration) or accidental consumption of high doses of supplements. Excess iron intake can cause overload and damage of internal organs. Oxidation of ferrous iron in haemoglobin can result in methemoglobinemia and an inability of erythrocytes to carry oxygen. In recent years, scientists have implicated some questions regarding iron and ruminants that need re-evaluation or further investigation, e.g. the upper tolerable concentration of Fe in drinking water, the relationship between inflammation and iron status, serum Fe as an indicator of inflammation, or ferritin as a predictive factor for iron deficiency anaemia in cattle