Mineral Nutrition for Ruminants

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Mineral Nutrition for Ruminants
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Major Minerals

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

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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
• Enzyme co-factor or component

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Mineral Deficiencies
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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

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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

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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)

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Copper, sulfur and molybdenum

• High sulfur molybdenum thiomolybdates
• Cu thiomolybdates insoluble complexes
• Thiomolybdates can result in reduced Cu
  absorption and systemic metabolism

NRC, 1996
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Mineral Toxicosis
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Maximum Tolerable Levels for Ruminants
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Copper Toxicosis

• Sheep particularly sensitive to copper
• 5 ppm Cu
• Excessive Cu builds up in RBC, causing Heinz-body
  formation and methemoglobin production
• Cant bind oxygen-chocolate blood
• Release of hemoglobin damages kidneys
• Avoid feeding cattle mineral

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Copper Toxicosis Treatment

• IV methylene blue to control metHb
• Copper chelators
• D-penicillamine
• Ammonium tetrathiomolybdate
• CuMo ratio of 101 or less

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Sulfur Toxicity in Ruminants

• Dietary sulfate reduced to H2S (gas)
• Eructate-reinhale
• Toxic in high amounts
• Polioencephalomalacia (PEM, brainers)

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Brain lesions due to S toxicity
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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

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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).

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60 of ruminal gas that is eructated is inhaled
Pka of HS- 7.04
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S Induced PEM
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Oxidative Stress

• Reactive oxygen species
• Byproduct of cellular respiration
• Roles in cell signalling
• Dangerous in excess
• Species
• Hydroxyl
• Superoxide
• Hydrogen peroxide

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Oxidative Stress

• Effects
• DNA damage
• Lipid peroxidation (oxidation of polyunsaturated
  fatty acids)
• Inactivation of some enzymes (oxidation of metal
  cofactors)

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Antioxidant Capacity

• Superoxide dismutase
• Superoxide anion to hydrogen peroxide
• Copper-Zinc SOD-cytosol
• Manganese SOD-mitochondria

http//en.wikipedia.org/wiki/Superoxide_dismutase
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Antioxidant Capacity

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

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Antioxidant Capacity

• Glutathione peroxidase
• Hydrogen peroxide to water
• Selenium dependent enzyme-4 selenium atoms per
  molecule

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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

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Iodine

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

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Goiter in lamb
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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)

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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

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Cobalt

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

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