1. Mineral Nutrition for Ruminants

3. Major Minerals Major (macro) minerals  Ca, P, K, Mg, Na, Cl, S  Included as % in diet Functions 

4. Trace Minerals Trace (micro) minerals  Cobalt, copper, iodine, iron, manganese, molybdenum, selenium and zinc all required  Chromium-no established requirement  Included as ppm or ppb in diet Function 

5. Milk Fever Symptoms included lack of appetite and paralysis Treatment is intravenous Ca borogluconate

6. Milk Fever Prevention  mEq(Na + + K + ) – mEq(Cl - + SO 4 - )  Normal diet: +20 to +30 mEq/100g diet (electrolyte balance)  Anionic diet: -7 to -25 mEq/100g diet Induces mild acidosis, which increases tissue responsiveness to PTH  Ca release from bone to serum

7. Grass Tetany Fertilizing with K or N make it worse Symptoms include muscular twitching, collapse, convulsion  Treatment is IV Mg gluconate  Prevent with high Mag mineral (MagOx)

9. Copper, sulfur and molybdenum Cu + thiomolybdates insoluble complexes Thiomolybdates can result in reduced Cu absorption and systemic metabolism NRC, 1996

11. Maximum Tolerable Levels for Ruminants

12. Copper Toxicosis  5 ppm Cu  Excessive Cu builds up in RBC, causing Heinz-body formation and methemoglobin production  Can’t bind oxygen-chocolate blood  Release of hemoglobin damages kidneys Avoid feeding cattle mineral

13. Copper Toxicosis Treatment IV methylene blue to control metHb Copper chelators   Ammonium tetrathiomolybdate Cu:Mo ratio of 10:1 or less

16. Sulfur Toxicity in Ruminants Eructate-reinhale Toxic in high amounts  Polioencephalomalacia (PEM, brainers)

17. Brain lesions due to S toxicity

18. Polioencephalomalacia (PEM) Terminology  Polio =  Encephalo =  Malacia = Clinical signs  Subacute – head pressing, circling, ataxia, staggering, blindness, depression, stupor  Acute – blindness, seizures, comatose Can be caused by thiamine deficiency, lead or salt poisoning and high sulfur diets

19. S induced PEM Does not appear to be caused by thiamine or copper deficiency  No alterations of thiamine or its mono- and diphosphate esters in whole blood, brain, cerebrospinal fluid, or liver (Sager et al., 1990; Gould et al.,1991) Thiamine treatment can help reduce symptoms  Increase energy availability to the brain plays a key role in the tri-carboxcylic acid cycle and pentose shunt  Thiamine-supplemented groups also manifested PEM, even though clinical signs were not observed (Olkowski et al., 1992).

20. Oxidative Stress  Byproduct of cellular respiration  Roles in cell signalling  Dangerous in excess Species  Hydroxyl  Superoxide  Hydrogen peroxide

21. Oxidative Stress Effects   Inactivation of some enzymes (oxidation of metal cofactors)

22. Antioxidant Capacity  Superoxide anion to hydrogen peroxide  Copper-Zinc SOD-cytosol  Manganese SOD-mitochondria http://en.wikipedia.org/wiki/Superoxide_dismutase

23. Antioxidant Capacity  Hydrogen peroxide to water and oxygen  Consists of 4 parts, each containing a heme (iron) group

24. Antioxidant Capacity  Hydrogen peroxide to water  Selenium dependent enzyme-4 selenium atoms per molecule

25. Iodine  70-80% of body I - is in thyroid  T4 (thyroxine)  T3 (triiodothyronine)-3 times more active than T4  Controls rate of energy metabolism in cells

26. Iodine  Plants have “goitrogens” (goiter creating), block use of iodine Reduced growth Impaired reproduction-dead, weak or hairless young

27. Goiter in lamb

28. Selenium Function  Glutathione peroxidase (antioxidant)  Iodothyronine 5’-deiodinase-1 (T4 conversion to T3)

29. Selenium Deficiency   Reproductive problems such as retained placenta and low fertility, weak newborns

32. Cobalt Rumen microorganisms synthesize B12 from cobalt B12 dependent enzymes  Methylmalonyl-CoA mutase  Methionine synthetase

34. Mineral Deficiencies Severe (clinical signs) Marginal   Slight reductions in milk  Increased incidence of disease

35. Deficiencies Occur because   Presence of antagonist in diet  Low bioavailability of mineral

36. Mineral Sources Feedstuffs Mineral supplements Goal of supplementation program: 

37. Types of Supplement White salt Protein-molasses block Liquid supplement (molasses, corn steep, to suspend mineral)

38. Differences among supplements Amount of mineral provided Source of mineral used  Level of intake  Salt level (high level to limit)  Amount of carrier-molasses, grain by- products, flavoring agents