Trace metal exposure in different livestock production systems

Industrial and agricultural activities are associated with environmental pollution as these practices contribute to increase further the concentration of minerals derived from the parent rock, present naturally in the soil. Heavy metals (i.e., arsenic, cadmium, lead and mercury) and excessive levels of essential metals (such as copper and zinc) have negative effects on the health of both animals and humans. The exposure of animals to toxic elements or excessive levels of essential minerals could influence greatly the mineral content of different animal derived products for human consumption (i.e., meat, offal and milk) and may affect significantly human health. The exposure of livestock to different minerals varies depending on the animal husbandry practices adopted by the farmers, such as the use of mineral supplements in animals’ feed and the foraging practices of the farm (i.e., grazing, type of soil and forage contamination). This chapter focuses on the influence of different farming practices on the exposure of livestock to toxic and trace elements, emphasising the differences between the intensive and organic farming systems. The relationship between different farming practices and the mineral content of animal derived products, together with the implications of these farming practices for the consumers and environment are also discussed.