DEFICIENT AND EXCESS MINERALS IN FORAGE IN THE UNITED STATES

by A. M. Hartman ^

I n various articles in this Yearbook the reader will find references to areas in which there are deficiencies or excesses of certain minerals severe enough to cause trouble with livestock. Where are these areas? A questionnaire was sent to all States to get together whatever definite information there was on this problem, which is a comparatively new one in animal nutrition. Here are the results of the questionnaire. They deal with phosphorus, calcium, iodine, cobalt, copper, iron, fluorine, selenium, and cyanides. Undoubtedly the information is far from complete, but no comprehensive survey of this kind has previously been made.

IN MANY PARTS of the world, symptoms of or disease in livestock on certain areas have been traced to deficiencies of nutri- tionally essential elements in the available forage. In some of these areas, before the causes of the difficulties were discovered and remedial measures taken, there were serious economic losses as the result of impaired productive capacity and death of animals. Such deficient areas have been known for some years to exist in the United States, and the question of mineral deficiencies in forages has at one time or another been investigated by many of the State experi- ment stations. As a result of the cooperative w^ork of several bureaus of this Department and some of the experiment stations, a toxic condition that is sometimes fatal to livestock in certain of the Great Plains and w^estern mountain States has been found to be caused by consumption of native forage (and also grain) containing excessive quantities of selenium. In order to assemble for the Yearbook information on areas in each State where mineral deficiencies or excesses in the forage have been found to produce symptoms of malnutrition in livestock, a form letter requesting information bearing on this problem was sent to

i A. M. Hartman is Associate Chemist, Division of Nutrition and Physiology, Bureau of Dairy Industry. 1027 1028 YEARBOOK OF AGRICULTURE, 1939 each of the State experiment stations in October 1938. A map of the State was included for indicating affected areas. Rephes to these inquiries were received from every State. A number of the States indicated either that no such deficiencies or excesses were known or that no investigations of the question had been made. In addition, there were States in which the reporters intimated that there might be a mineral deficiency of one element or another in relation to animal requirements in the State, either generally or in certain portions. This is true particularly in regard to phosphorus—for example, m a number of States of the Atlantic and Gulf Coastal Plains other than those listed as containing phosphorus-deficient areas. In none of these cases, however, were deficiency symptoms in animals reported. Statements would indicate that surveys of these States should be made before definite conclusions are drawn. In fact, there is sufficient evidence in the replies from many States to warrant much more thorough surveys than have yet been made of conditions with regard to various mineral elements. As suggested in the article What Do We Need to Know in Livestock Nutrition? (p. 1045), there is evidently great need for more data and for the compilation, interpretation, and correlation of all data on (1) soil and climatic conditions, (2) mineral content of forage, and (3) animal observations, to determine whether or not optimum conditions for mineral nutrition in the raising of livestock prevail in many range and pasture areas in the United States. Although it was not specifically requested in the letter, several States reported toxic efi'ects on livestock of mineral matter in drinking water. Only in the case of fluorine have reports of such effects been included in the compilation. Careful consideration has been given to the information