ROLE OF MICRO OR TRACE MINERALS IN LIVESTOCK HEALTH

ROLE OF MICRO OR TRACE MINERALS IN LIVESTOCK HEALTH

Macro minerals are present at larger levels in the animal body or required in larger amounts in the diet. Macro minerals include calcium, chlorine, magnesium, phosphorus, potassium, sodium, and sulfur.

Micro minerals are often referred to as trace minerals, meaning they are present at low levels in the body or required in smaller amounts in the animals diet. Micro minerals include chromium, cobalt, copper, fluorine, iodine, iron, manganese, molybdenum, selenium, and zinc.

Micro-minerals

Trace minerals/Micro minerals play an essential role in various metabolic, enzymatic and biochemical reactions in poultry. They also have a role to play in the mechanism of nutrient circulation in the animal organism.Deficiency of these important micro nutrients would result in deficiency diseases, poor growth, low egg production and low feed efficiency.

The trace minerals in feed can be further classified into regular trace minerals and ultra-trace elements. If the requirements are less than 1mg/kg diet (<1ppm, usually few ppb) they can be called ultra-trace elements. However their requirements are not established because most of them are toxic, with very little safety range. Arsenic, boron, cadmium, chromium, cobalt, fluorine, molybdenum, selenium and many more minerals may be classified under ultra-trace elements. Unspecified variations in the performance of birds in farms with the same hybrid, feed, micro environment and management might be partly due to variations in the levels of these ultra-trace elements in the water. Hence they are not usually supplemented in the feed and the natural levels in various feedstuffs and drinking water will be sufficient.

There are 27 essential minerals for animals, and those found in the diets in less than 100 ppm are considered micro or trace minerals {TM}. Generally, their levels in the diets will be measured in ppm,
mg/kg or g/ton. In poultry species, the TM that are supplemented are zinc (Zn), copper (Cu), manganese (Mn), iron (Fe), iodine (1), and selenium (Se). Other trace minerals like cobalt (Co),chromium (Cr), and molybdenum (Mo) are not generally added in poultry mineral premixes, but they can have some effects in poultry.

• Iron: Necessary for blood and some enzyme formation. The precise minimum requirements have not been determined for various classes of livestock, but 80mg of iron per kg of diet is more than adequate for most animals. Deficiencies are most often found in young pigs (other animals much less sensitive): Laboured breathing, flappy wrinkled skin, oedema of head and shoulders, pale eyelids, ears and nose. Prevention/cure: A few drops of ferrous sulphate or similar daily during the first 3-4 weeks. Salt licks containing iron. Cattle fed with roughages iron will be sufficient in general.

• Iodine: Needed for the production of Thyroxin in the thyroid gland. A level of 0.25 mg/kg air dried diet is considered adequate for most classes of livestock. Dairy cows should be provided with 0.5 mg iodine/kg dry matter feed.
  Deficiency symptoms: Goiter at birth or soon after, Hairlessness at birth, infected navels, dead or weak at birth. Prevention: mix normal iodized salt (table salt) into the salt licks of the livestock.

• Cobalt: Needed in vitamin synthesis. For cattle and sheep, feed containing from 0.05-0.10 mg of cobalt/kg feed prevents any cobalt deficiency. For pigs cobalt is only needed as part of Vit B12. Several areas in India have cobalt deficient soils, producing feed deficient in cobalt.A feed analysis will show whether feed in your area is cobalt deficient.
  Deficiency symptoms are simply those of malnutrition: poor appetite, unthriftiness, weakness, anaemia, decreased fertility, slow growth and decreased milk and wool production. There are number of disorders due to cobalt deficiency characterized by emaciation (wasting disease ), pining, anaemia and listlessness. Although excess cobalt can be toxic to animals, there is a wide margin of safety level. Thus cobalt toxicity is generally unlikely. Prevention and cure: Where cobalt deficiency is diagnosed, 12.5g of any cobalt salt, such as cobalt chloride, cobalt sulphate or cobalt carbonate can be mixed with 100 kg of normal cattle salt. Barley, grain, Lucerne and Sorghum are relatively high in cobalt.

• Copper: needed for blood and hair production as well as in the enzyme system. Where diets are not high in Molybdenum and/or sulphate the following levels of copper per kilo of diet dry matter have been found adequate:
  • Dairy cattle: 10 mg/kg
  • Beef cattle and sheep: 4-5 mg/kg
  • Pigs: 6 mg/kg
  • Horses: 5-8 mg/kg
• High levels of Molybdenum and/or sulphate create unusable salts and may increase the copper requirements 2-3 times. Many areas in India have copper deficiency in the soils and produce feed deficient in copper. Deficiency symptoms are not specific and may include any of the following: Bleaching of hair in cattle especially around the eyes, abnormal wool growth in sheep, muscular incoordination, weakness at birth, anaemia, severe diarrhoea. Prevention and cure: Supplementation of livestock with copper in copper deficient areas is essential. This can be done by using trace mineralized salt containing from 0.25-0.50% copper sulphate. Pigs may be fed up to maximum 250 g copper/kg dry feed. More than 100 mg copper per kilo dry matter may be toxic to cattle and over 50 mg/kg will be toxic for sheep. It is also possible to repair your grazing areas for especially ruminants by upgrading the soil content of copper according to soil analysis recommendations. Generally grass and fodder deficient in copper have yellow or burnt leaf tips and low rates of production. Soybean, aerial parts, Cocoa pods and hulls, Cassava, foliage silage, Cowpea, aerial parts, Sunflower, cake, Maize Stover, Coffee hulls Cotton seed meal, Barley straw and Wheat bran can be sources of copper.

• Fluorine: necessary for healthy teeth, but excess may weaken and stain the teeth. In India fluorine deficiencies are not common, but drinking water especially from boreholes often contain very high levels of fluorine. If the levels of fluorine are too high water can be filtered through a filter containing burnt bones, which will absorb most of the fluorine. This is more practical for human water consumption than for livestock. In most parts of  India highlands there is excess of fluorides in surface water and ground water. Harvesting rainwater for domestic use can ameliorate the problem. Water can also be treated to lower the fluoride level.

• Manganese: influences oestrus, ovulation, foetal development, udder development, milk production, growth and skeletal development. Requirements:
  • Dairy cattle: 40 mg/kg of dry matter feed
  • Beef cattle and sheep: 5-20 mg per kg dry matter feed
  • Pigs: 10-20 mg/kg dry matter feed.
• Deficiency symptoms noted from areas deficient in soil manganese include: delayed oestrus, reduced ovulation, abortions, resorptions, deformed young, “knuckle over” in calves, poor growth. Supplementation is easily done with trace mineralized salts containing 0.25% manganese. Rice products, Guinea grass, and Napier grass van be rich in manganese.

• Molybdenum: Important in poultry as it stimulates uric acid formation, and in ruminants stimulates action of rumen organisms. Molybdenum deficiencies have only been observed in poultry in special cases. Molybdenum supplementation is normally not recommended in livestock production. High amounts limit copper availability. Soybean cake, Rice bran, Lucerne, Wheat bran and Sunflower cake can be high in molybdenum.

• Selenium: works in vitamin E absorption and utilization.
  Requirements: about 0.1 mg or less per kg dry feed. Deficiency symptoms include: Nutritional muscular dystrophy in lambs and calves, retained placenta in cows, heart failure, paralysis, poor growth, low fertility, liver necrosis, pancreatic fibrosis in chicks. Many areas in India are known to have selenium deficiency of the soils. If selenium deficiency is expected, a soil or feed sample can be sent to any of the major laboratories for analysis. Supplementation must be done very carefully as selenium in too large quantities is poisonous and causes the same problems as selenium deficiency. 1 gram Selenium in the form of sodium selenite can be added to 10 kg dry feed in deficient areas (=10g or 2 teaspoons per 100 kg feed- really not much). Fish meal, Wheat bran, Sorghum grain, Sunflower cake, Lucerne, Wheat grain, Soybean hulls and Rice bran are good sources of selenium.
• Zinc: promotes growth and thriftiness. Promotes wound healing, related to hair and hoofs/claws and wool growth. Deficiencies mostly found in pigs fed on concrete floors. Deficiency symptoms include: general unthriftiness, poor growth, unhealthy looking hair, skin and wool, slow wound healing. Pigs can be supplemented with 50 mg of zinc per kg of dry feed or as trace mineralized salt. Good sources of zinc can be: Soybean, aerial parts, Sugarcane forage, Sunflower heads, Banana, stalks, Neem tree, leaves, Mango leaves, Jackfruit leaves, Maize bran and Fish meal.

A well balanced mineral salt mixture adjusted to local conditions is the easiest way to ensure good mineral balance in animal feeds. It is not common to have feeds analysed for minerals and trace-elements because of the high price of analysing. Free ranging livestock do get reasonable adequate quantities from nature or from sites with natural minerals licks. Commercial mineral mixtures are available and are highly recommended for high yielding cows and intensively raised chickens and pigs.

Dr. Ajeet singh,livestock consultant, Gorakhpur

Reference-On request

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