Cadmium and the Welfare of Animals

Cadmium is a toxic agent that affects human health, and in this article its impacts on animal health and welfare are examined. There is evidence that some farm animals can detect and actively avoid it when presented with feedstuffs with a range of cadmium concentrations. Concentrations in soil are usually greater than those in feedstuffs because most plants do not transport cadmium effectively into stem and leaf material. Hence, herbivores that consume some soil while grazing are particularly at risk, especially wild herbivores that are relatively long-lived, such as deer, as cadmium accumulates in their organs over time. Deer and other wild species have been found to show evidence of nephrotoxicosis as a result of cadmium consumption, even in relatively unpolluted regions. Concomitant stresses such as inadequate food supplies may exacerbate cadmium toxicity in these animals. The chemical form of cadmium is of major significance in determining the toxicity, and pigs and other monogastric animals are believed to be at risk because they cannot produce the enzyme phytase in their gastrointestinal tract. Synergistic effects with other toxic elements, such as lead, exacerbate the adverse effects of cadmium on pig welfare, and it has been established that cadmium has the ability to reduce the uptake of some essential elements, such as zinc. It is concluded that cadmium pollution has the potential to adversely affect the welfare of animals, especially animals in the wild.