Author
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Goff, Jesse |
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Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 6/20/2002 Publication Date: 12/13/2004 Citation: Goff, J.P. 2004. Minerals. In: Reece, W.O., editor. Dukes' Physiology of Domestic Animals, 12th edition. Ithaca, NY: Cornell University Press. p. 575-599. Interpretive Summary: Technical Abstract: A number of inorganic elements have been shown to be essential for normal growth and reproduction of animals. Those required in greater quantities are referred to as macrominerals and this group includes calcium, phosphorus, sodium, chlorine, potassium, magnesium, and sulfur. The macrominerals are important structural components of bone and other tissues and serve as important constituents of body fluids. They play vital roles in the maintenance of acid-base balance, osmotic pressure, membrane electrical potential and nervous transmission. Those elements required in much smaller amounts are referred to as the trace minerals. This group includes cobalt, copper, iodine, iron, manganese, molybdenum, selenium, zinc, and perhaps chromium and fluorine. Other elements have been suggested to be essential but these are generally not considered to be of practical importance. The trace minerals are present in body tissues in very low concentrations and often serve as components of metalloenzymes and enzyme cofactors, or as components of hormones of the endocrine system. A thorough discussion of the dietary requirements of each specie for each mineral is beyond the scope of this chapter - the reader is referred to the publications on nutrient requirements of domestic animals produced by the National Research Council of the National Academy of Science. For all minerals considered essential, detrimental effects on animal performance can be demonstrated from feeding excessively high levels. Generally, the dietary level required for optimal performance is well below levels found to be detrimental to performance. However, toxicity from several of the essential minerals, including fluorine, selenium, molybdenum, and copper are unfortunately problems that can occur under practical feeding conditions. The National Research Council’s Mineral Tolerance of Domestic Animals (1980) describes signs of toxicosis and the dietary concentrations of minerals that are considered excessive. Certain elements such as lead, cadmium, and mercury are discussed because they should always be considered toxic and are of practical concern because toxicosis from these elements unfortunately occasionally occurs. The goals of this chapter are to familiarize the veterinary student with: 1) The role each mineral has in body functions; 2) Homeostatic mechanisms for each mineral; 3) Deficiency symptoms; 4) Toxicity symptoms; 5) Syndromes of special concern in veterinary medicine. |
