Mineral Supplements For Beef Cattle

Mineral Supplementsfor Beef CattleLawton StewartExtension Animal Scientist - Beef Cattle

IntroductionBeef cattle require a number of minerals for optimal growth and reproduction. Selecting the correct mineral supplement is important for maintaining healthy animals,and optimal growth and reproduction. Since high-quality forages and/or grains canfurnish a large portion of the required minerals, producers should select supplementsthat will meet animal requirements and avoid excesses that reduce profits and leadto unnecessary mineral excretion. Minerals not provided by feed can be easily andinexpensively supplied with a simple mineral supplement. A good mineral program forbrood cows should cost about 10 to 20 per year. This bulletin provides informationon basic mineral nutrition for most forage and feeding programs in Georgia.Minerals essential to cattle nutrition are classified as either macrominerals or microminerals, depending on whether they are found at levels greater than or less than100 parts per million (ppm) in the animal’s body.Mineral Supplements for Beef Cattle2UGA Cooperative Extension Bulletin 895

MacromineralsThe macrominerals beef cattle require includecalcium, magnesium, phosphorus, potassium, sodium, chlorine and sulfur. Macromineral requirements and maximum tolerable levels for beefcattle are shown in Table 1.Concentrates contain moderate to high concentrations of phosphorus. Protein supplements such ascottonseed meal and soybean meal contain moderate concentrations, whereas many by-productfeeds such as distillers grains, corn gluten feedand wheat middlings, have high phosphorusconcentrations.Calcium and PhosphorusCalcium and phosphorus are the major mineral components of the skeleton. Ninety-ninepercent of total body calcium and 80 percent oftotal body phosphorus are stored in the bones.The skeletal stores of calcium and phosphorusare used to meet short-term dietary inadequacies.Long-term deficiencies of either can cause bonesto weaken and even break.Calcium and phosphorus also play important roles in other bodily functions. A decreasein either or both can cause a decrease in weightgain and/or a decrease in efficiency of gain. During lactation, low amounts of either will reducemilk production. A superior milking cow requiresthree times more calcium than a non-lactatingcow. A phosphorus deficiency can delay pubertyin heifers and can delay mature beef cows fromreturning to heat following parturition. Cattlealso need correct amounts of calcium for the nervous and muscular systems to function properly.Proper utilization of calcium and phosphorusis affected not only by the amount of each mineralfed, but also by their ratio. The optimum Ca:Pratio is about 1.5:1, with a range of 1:1 to 4:1 beingsatisfactory. In some high-concentrate rations,ratios higher than 2:1 have been successful.Most grasses are adequate in calcium. Legumes such as alfalfa, peanut, clover and soybeanhay are good sources of calcium, but corn silageand sorghum silage are poor sources of calcium.In general, most concentrates are relatively poorcalcium sources. One exception is citrus pulp,which is relatively high in calcium concentration(1.9 percent). Corn, corn by-product feeds andsorghum grain are particularly low in calciumcontent, and cattle fed grain or corn silage-baseddiets require calcium supplementation.Most forages are low in phosphorus, particularly late in the growing season. Cattle are morelikely to be phosphorus-deficient during thewinter, when they often subsist on dry forages.UGA Cooperative Extension Bulletin 895Sodium and ChlorineSodium and chlorine (salt) provide for theproper function of the nervous and muscularsystems. They help regulate body pH and theamount of water retained in the body. A deficiency of these elements causes loss of appetiteand inefficient weight gains or body weight loss.Sodium is commonly deficient in diets, but chlorine levels are usually adequate. Both mineralsare present in soft tissues and fluids and there isvery little storage of these elements, so a constant,daily source of sodium and chlorine must be provided. Cattle will voluntarily consume more saltwhen forage is young and succulent than when itmatures. Silage-fed cattle will consume more saltthan those fed hay, and consumption is higher incattle fed high-roughage diets than in those onhigh-concentrate diets. As a rule of thumb, cattleconsume 0.005 to 0.010 percent of their bodyweight as salt daily. For example, a mature cowweighing 1,200 pounds would consume 0.06 to0.12 pounds (1,200 x 0.00005 0.6), or 1.0 to 1.9ounces of salt daily.MagnesiumMagnesium is essential for proper enzymeand nervous system function and for efficientcarbohydrate metabolism. A magnesium deficiency is uncommon except for cows grazinglush-growth fescue or small grain pastures during the late winter and early spring, which maycause grass tetany, a serious and sometimes fatalmetabolic disorder. A high rate of nitrogen andpotassium fertilization contributes to grass tetany.Excess potassium inhibits magnesium absorptionin both forage and animals. Grass tetany usually occurs following an extended period of coldweather combined with high levels of nitrogenand potassium fertilization. Mature lactatingcows are particularly susceptible to grass tetany.3Mineral Supplements for Beef Cattle

Grass tetany can usually be prevented byfeeding cattle a mineral mixture containing magnesium oxide. A mineral mixture containing 10 to14 percent magnesium consumed at 4 ounces perday should provide adequate magnesium. Adequate salt intake is also important for preventinggrass tetany. Avoid using hard blocks to supplement salt when cattle are at risk for grass tetany;supply salt in a loose form to allow for adequatesalt consumption. When grass tetany is not a risk,blocks can be used to supplement minerals, provided trace minerals are elevated to account forlower intake of block versus loose salt minerals.Animals with grass tetany respond almost immediately to an intravenous infusion of calciummagnesium gluconate.potassium for grazing cattle and supplementationis rarely needed. However, potassium may occasionally be low in stockpiled forages or hay thatwas rained on prior to baling because potassiumis soluble and will leach from the forage.SulfurSulfur is a part of the essential amino acidsmethionine and cystine, which make up protein.A sulfur deficiency in beef cattle diets is not likelyto occur under normal feeding conditions. Sulfuris more likely to be in excess, which can interferewith the metabolism of copper, resulting in acopper deficiency. Also, excess sulfur can reducefeed intake and cause a brain lesion conditionknown as polioencephalomalacia (PEM). Certainby-products such as distillers grains and corn gluten feed contain higher concentrations of sulfur,which should be taken into account in rationbalancing. Sulfur is often added indirectly to themineral mix through sulfate forms of the microminerals.PotassiumPotassium functions in acid-base balance, osmotic pressure and the amount of water retainedin the body. Grasses, particularly early lushspring growth, contains adequate amounts ofTable 1. Macro mineral requirements and maximum tolerable levels for beef cattle.MineralLactating CowsDry CowsGrowing CalvesMaximum Tolerable LevelCalcium, %0.310.180.58—Magnesium, %0.100.120.200.40Phosphorus, %0.210.160.26—Potassium, %0.600.600.703.0Sodium, %0.070.070.10—Sulfur, %0.150.150.150.40NRC, 1996. Adapted from NRC. Nutrient Requirements of Beef Cattle, Sixth Edition.Mineral Supplements for Beef Cattle4UGA Cooperative Extension Bulletin 895

MicromineralsBeef cattle require 10 microminerals. Seven ofthe 10 microminerals have established requirements, including iron, manganese, copper, zinc,selenium, cobalt and iodine. The micromineralschromium, molybdenum and nickel do not havean established requirement and are not normallyadded to mineral mixes fed to beef cattle. Onlythree of the microminerals (copper, zinc andselenium) are likely to be deficient in grazing beefcattle diets. Micromineral requirements and maximum tolerable levels for beef cattle are shown inTable 2.supplemented as ethylenediamine dihydroidide(EDDI). The maximum legal supplementation ofEDDI is 50 mg per head per day. In some instances, EDDI has been included in diets to preventfoot rot; however, the amount of EDDI requiredto prevent foot rot is much higher than requirements and most likely will not prevent foot rotwhen included at the legal maximum.IronIron is primarily required for the formation ofhemoglobin. Deficiency symptoms include anemia, depressed immunity and decreased weightgains. Iron deficiency is rarely observed in grazing cattle. Iron oxide is often included in mineralmixtures, but is unavailable to the animal andserves only as a coloring agent to give the minerala dark red color. Iron sulfate is available to theanimal and should be used if iron supplementation is needed.CobaltCobalt functions as a component of vitaminB-12, which is synthesized in the rumen by bacteria. The primary deficiency symptom is loss ofappetite and poor growth. Most forages in theSoutheast have adequate levels of cobalt; however, it is usually added in the mineral mix atapproximately 10 ppm to ensure no deficiencies.High-grain diets require more cobalt than foragebased diets, and cobalt should always be includedin the mineral mix when feeding grain-baseddiets.ManganeseManganese is required for normal reproduction, and fetal and udder development. Manganese deficiency is rare and unlikely to be a problem in grazing cattle in Georgia. Manganese oxideis the most common form of manganese used inmineral mixes. Corn-based diets are low in manganese and supplementation is necessary whenfeeding these diets.CopperCopper is the most common micromineral deficiency in grazing cattle. Copper is an importantcomponent of many enzyme systems essentialfor normal growth and development. Deficiencysigns include reduced fertility, depressed immunity and reduced pigmentation of hair (black hairchanges to red). Dietary deficiencies can occur,but most deficiencies are caused by the consumption of antagonists, which reduces copper absorption. Copper should be supplemented as coppersulfate, tribasic copper chloride or an organiccomplexed form because copper oxide is verypoorly absorbed.SeleniumSelenium can be deficient in some areasof Georgia. Selenium deficiency causes whitemuscle disease (similar to muscular dystrophy)in newborn calves. Selenium deficiency can alsocause calves to be weak at birth and increase theirsusceptibility to calfhood diseases like scours.Increased rates of retained placentas and poorreproductive performance are often observed incows with selenium deficiencies.Selenium is generally added to mineral mixtures in the form of sodium selenite. Seleniumis very toxic and should be used in a premixedform only. The FDA allows selenium to be usedat a level not to exceed 0.3 ppm of the dry matter in the total diet of beef cattle. In areas whereIodineIodine is an essential mineral for function ofthe thyroid hormones that regulate energy metabolism. The first sign of iodine deficiency isgoiter in newborn calves. Iodine is rarely deficientin cow herds in the Southeast. Iodine is usuallyUGA Cooperative Extension Bulletin 8955Mineral Supplements for Beef Cattle