Trace minerals

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Ngày đăng: 30/11/2016, 13:38

MINERALS REQUIRED IN LIVESTOCK DIETS • Major minerals (Required in large quantities) Beef Dairy Swine Ca, % P, % Mg, % Na, % Cl, % K, % S, % Finishing Cow 15-.3 12-.23 10 12 06 08 6 15 15 Chicken Dry Lactating Finishing Sow 75 25 04 04 15 25 10 15 25 30 08 12 1.0 1.5 23 20 26 - Broiler Layer 3.5 8 05 05 15 15 15 15 4 - • Minor minerals (Required in very small quantities Fe, ppm Cu, ppm Zn, ppm Mn, ppm I, ppm Co, ppm Se, ppm Mo Cr 30 10 30 20 50 10 10 50 10 30 40 50 10 10 100 20 80 50 60 30 30 100 20 70 50 60 20 30 60 60 14 15 80 50 10 14 15 80 50 60 35 15 45 35 35 30 10 • Minerals are often overfed – Levels of minerals commonly fed in industry to swine Mineral Ca P Mg Na K Fe Cu Zn Mn Level fed, % of requirement 160-190 140-150 400-500 147-190 390-423 470-776 440-667 298-334 770-3100 – Reasons for overfeeding of minerals • • • • • High levels in feeds Supplementation to provide safety margin No consideration of mineral bioavailability Free choice feeding of trace mineral salt Use of Cu and Zn salts as growth promotants for swine and poultry Dose, ppm Cu 100-250 Zn 2000-4000 • Utilization rates of most minerals are low Utilization rate Excretion rate (% of intake) 30-50 50-70 20-50 50-80 15-30 70-85 10-25 75-90 5-20 80-95 5-30 70-95 5-30 70-95 5-30 70-95 5-10 90-95 Ca P Mg Na K Fe Cu Zn Mn – Factors mineral utilization rates • Mineral sources – Organic mineral (Chelates) > SO or CO3 salts > oxides • Level fed – Low levels > high levels • Interactions with other minerals – High K reduces Mg absorption – High Zn reduces Cu absorption – Low Cu reduces Fe absorption • Processing – Grinding increases mineral absorption • Age and nutritional status of animals – Young animals absorb minerals better than adults • All minerals are toxic to animals if fed in excess – Maximum tolerable concentrations Ca, % P, % Mg, % NaCl, % K, % S, % Fe, ppm Cu, ppm Zn, ppm Mn, ppm Mo, ppm I, ppm Co, ppm Se, ppm Cr, ppm Beef 4 1000 100 500 1000 50 10 1000 Dairy 4 1000 100 500 1000 10 50 10 1000 Swine 1.5 3000 250 1000 400 20 400 10 1000 – Causes of toxicities • Oversupplementation • Poor formulation and/or mixing – Wrong feeds fed to wrong species • High concentrations in feedstuffs Poultry 4-1.2 8-1.0 2 1000 300 1000 2000 100 300 10 1000 Sheep 500 25 300 1000 10 50 10 1000 – Examples • High K forages (associated with overfertilization) – Health effects » Milk fever A calcium deficiency occurring to dairy cows in early lactation Results in tetany and death, if untreated Caused by overfeeding cations, particularly K, during the dry period Prevents resorption of Ca from bone » Grass tetany A Magnesium deficiency occurring to animals grazing lush, heavily fertilized grass pastures in the spring Results in tetany and death, if untreated Caused by low Mg content of lush forage and inhibition of Mg absorption by high levels of K and N • High Se forages – Causes » High Se soils in western U.S » Plant species that accumulate Se – Health effects » Se toxicity Lameness Blind staggers (Labored breathing and ataxia (loss of coordination) – Not yet associated with manure application CONCERNS WITH EXCESS MINERALS IN SOILS • In soils, most minerals act like P – Minerals bind to soils high in clay or organic matter • Particularly occurs at pH>6 • Occurs particularly near soil surface • Minerals move to water sources with soil erosion – Minerals not bind to soils that are high in sand or have a low pH • Travel with infiltrating water into ground water sources – Most minerals have limited bioavailability to plants • < 40% • Results in accumulation of trace minerals in soils – Example: » In areas where swine manure has been heavily applied in North Carolina: soil Zn increased times soil K increased times soil Cu increased times • Concern – Once trace minerals have accumulated in the soil, they’re difficult to remove Environmental effects of excessive application of manure mineralsMinerals of most concern – P, NaCl, K, Cu, Zn • Effects – Toxic to plants • NaCl, Cu, Zn, Mn – Detrimental or toxic to animal health – May enter water resources with soil erosion or water infiltration METHODS TO LIMIT MINERAL EXCRETION IN MANURE • Use of precision nutrition of minerals – Limit safety margins when feeding minerals – Utilize mineral sources with high bioavailability • Must balance for available minerals rather than total minerals – Balance for individual minerals rather than using complete trace mineral premixes • Requires rapid feed analysis – Limit use of free choice trace mineral salt • Utilize phase feeding • Utilize separate sex feeding • Limit feed waste
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