Cadmium exposure and consequences for the health and productivity of farmed ruminants

This paper reviews Cd exposure and consequences for the health and productivity of farmed ruminants. In farmed ruminants, Cd exposure may be associated with a number of different activities, including industrial processing, mining, and agricultural practices, and is also higher in soils in some geographic regions. Cd kidney concentrations increase with age and Cd exposure. Although Cd toxicity in farmed ruminants has been demonstrated experimentally, there are no published reports of naturally occurring Cd toxicity in farmed ruminants. Clinical signs of Cd intoxication are unlikely with a daily dietary Cd intake of less than 5 mg/kg feed, which is 5–10 times higher than the maximum permitted Cd concentration in ruminant feed in the European Union. In farmed ruminants, Cd levels in tissue are largely dependent on the Cd content of diet. However, many factors affect Cd availability, relating to soils, plants and the presence of other trace elements including Ca, Cu, Fe, Mn, Mo, Se and Zn. Experimental studies have highlighted the ability of Cd to alter trace element status, and the protective effect of good mineral status, however, there remain gaps in knowledge of the impact of these interactions on the health and productivity of farmed animals.