1. Mineral Nutrition for Ruminants

3. Major Minerals Major (macro) minerals Functions
Ca, P, K, Mg, Na, Cl, S
Included as % in diet
Functions
Structural
Nerve
Electrolytes
Osmotic balance

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

5. Mineral Deficiencies

6. Milk Fever Metabolic disease at/after parturition in dairy cows
Rapid in serum Ca because Ca is lost to colostrum secretion
Symptoms included lack of appetite and paralysis
Treatment is intravenous Ca borogluconate

7. Milk Fever Prevention
Include anionic salts in diet for 3-5 wks prior to parturition
mEq(Na+ + K+) – mEq(Cl- + SO4-)
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

8. Grass Tetany Hypomagnesemia in ruminants
Usually following lush spring growth
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)

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

12. Mineral Toxicosis

13. Maximum Tolerable Levels for Ruminants

14. Copper Toxicosis Sheep particularly sensitive to copper
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

15. Copper Toxicosis Treatment
IV methylene blue to control metHb
Copper chelators
D-penicillamine
Ammonium tetrathiomolybdate
Cu:Mo ratio of 10:1 or less

18. Sulfur Toxicity in Ruminants
Dietary sulfate reduced to H2S (gas)
Eructate-reinhale
Toxic in high amounts
Polioencephalomalacia (PEM, brainers)

19. Brain lesions due to S toxicity

20. Polioencephalomalacia (PEM)
Terminology
Polio = gray matter
Encephalo = brain
Malacia = tissue death
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

21. 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).

22. 60% of ruminal gas that is eructated is inhaled
Pka of HS- = 7.04

23. S Induced PEM

24. Oxidative Stress Reactive oxygen species Species
Byproduct of cellular respiration
Roles in cell signalling
Dangerous in excess
Species
Hydroxyl
Superoxide
Hydrogen peroxide

25. Oxidative Stress Effects DNA damage
Lipid peroxidation (oxidation of polyunsaturated fatty acids)
Inactivation of some enzymes (oxidation of metal cofactors)

26. Antioxidant Capacity Superoxide dismutase
Superoxide anion to hydrogen peroxide
Copper-Zinc SOD-cytosol
Manganese SOD-mitochondria

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

28. Antioxidant Capacity Glutathione peroxidase Hydrogen peroxide to water
Selenium dependent enzyme-4 selenium atoms per molecule

29. Iodine Function- part of thyroid hormone (metabolism rate)
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

30. Iodine Deficiency “goiter” enlarged thyroid gland Reduced growth
Plants have “goitrogens” (goiter creating), block use of iodine
Reduced growth
Impaired reproduction-dead, weak or hairless young

31. Goiter in lamb
Goiter

32. Selenium
Regulated by the FDA, because relatively low levels toxic (i.e. 10x requirement)
Function
Glutathione peroxidase (antioxidant)
Iodothyronine 5’-deiodinase-1 (T4 conversion to T3)

33. Selenium Deficiency Deficient in many areas of U.S. Muscular dystrophy
Sheep-white muscle disease
Reproductive problems such as retained placenta and low fertility, weak newborns

35. White muscle disease? Other se deficiency

36. Cobalt Essential component of B12 Required by ruminants
Rumen microorganisms synthesize B12 from cobalt
B12 dependent enzymes
Methylmalonyl-CoA mutase
Methionine synthetase