Providing mineral supplementation on pasture
Goats require many minerals for basic body function and optimum production. Providing a complete goat mineral or a 50:50 mix of trace mineralized salt and dicalcium phosphate free choice is advisable under most situations. Make sure that mineral mixes are kept dry and clean, and that your goats eat them, and record how much is consumed. Major minerals likely to be deficient in the diet are salt (sodium chloride), calcium, phosphorous and magnesium. Trace minerals likely to be low in the diet are selenium, copper, and zinc.
Most forages are relatively high in calcium (grass: less than 0.5%; legumes: more than 1.2%), so calcium is low only if high grain diets are fed, which would be unusual for meat goats. Low quality, mature or weathered forages will be deficient in phosphorous, especially for high and average lactating does. For example, bermudagrass hay harvested at 7 to 8 weeks regrowth only contains 0.18% phosphorous. The ratio of calcium to phosphorous in the diet is important and should be kept about 2:1 to 3:1 (Table 1).
|TABLE 1. DAILY NUTRIENT REQUIREMENTS FOR MEAT PRODUCING GOATS1,2|
|Early||Late||Avg Milk||High Milk|
|Dry matter, lb||2.0||3.0||4.5||4.5||4.5||5.0||5.0|
1 Nutrient Requirements of Goats in Temperate and Tropical Countries. 1981. National
Grass tetany is associated with low levels of magnesium in the blood. Grass tetany can occur when goats in early lactation are grazing lush, leafy cereal grains, annual ryegrass or grass/legume pastures heavily fertilized with nitrogen on soils low in phosphorous but high in potassium. It mostly affects does in early lactation and especially the highest-producing animals. Under those conditions, it is advisable to provide a mineral mix that contains 5 to 10% magnesium.
Selenium is marginal to deficient in most of the Southeast. Trace mineralized salts that include selenium should be provided to the goat herd at all times. In case selenium is absent, producers should encourage their local feed store to include it in commercial mixes or to order trace mineralized salts that contain selenium.
Copper requirements for meat goats have not been definitively established, although requirements for dairy goats have been established in Europe. Growing and adult meat goats are less susceptible to copper toxicity than sheep, however, but their tolerance level is not well known. Young, nursing kids are generally more sensitive to copper toxicity than mature goats, and cattle milk replacers should not be fed to nursing kids. Mineral mixes and sweet feed should contain copper carbonate or copper sulfate because these forms of copper are better utilized by the goat than copper oxide. Grains are generally lower in copper than forages. However, copper levels are of limited value in assessing adequacy unless forage concentrations of copper antagonists such as molybdenum, sulfur, and iron are also considered.
Forages, especially low quality forages, often contain concentrations of zinc that are thought to be below recommended levels for ruminants. However, zinc requirements of goats have not been defined, and little is known regarding factors that affect zinc availability in forages.
Luginbuhl, J-M. 2006. Pastures for Meat Goats. In: Meat Goat Production Handbook, ed. T.A. Gipson, R.C. Merkel, K. Williams, and T. Sahlu, Langston University, ISBN 1-880667-04-5.