Organic Trace Minerals in Ruminant Nutrition: Production, Reproduction, Health, Economics, and Environmental Implications

Trace elements have an important role in animal production, reproduction, immunity, and overall health, as they are functional components of numerous metabolic events occurring in the body. Two broad categories of sources available to supply the trace mineral elements are inorganic and organic sources. Inorganic mineral sources are the common sulfates, oxides, chlorides, and carbonates of the elements, and these can differ in their efficacy or bioavailability. The other category is the often referred to and marketed as organic mineral “chelates” or “complexes”. Recently, the inclusion of organic sources of mineral supplements to livestock diets has been suggested on the basis that they are relatively more bioavailable than the inorganic forms. Organically bound trace minerals as relevant in ruminant nutrition include zinc, manganese, copper, iron, chromium, selenium, etc. Research supports that adding organic mineral complexes improves production responses in terms of growth, milk production, and reproduction. Furthermore, organic mineral complexes have greater impact on reducing the negative interactions of trace minerals with other minerals and/or feed components, which otherwise lower the bioavailability of particular trace minerals in animals. In addition, another potential application for organic mineral sources—which is currently receiving greater attention—is their use to reduce environmental pollution associated with mineral excretion, thereby supporting sustainable animal agriculture. Notwithstanding their relative edge over inorganic minerals on bioavailability, the cost of organic minerals will be a major inhibitory factor in decision making on whether or not to use them, which entails to generate a feasible cost-to-benefit ratio before advocating supplementation of minerals from organic sources. In this backdrop, this chapter discusses the role of trace minerals in ruminants, use of organic mineral complexes, and their impact on production, reproduction, health, immunity, as well as their environmental implication.