Mineral Nutrition for
Ruminants
Major Minerals

Major (macro) minerals
 Ca,
P, K, Mg, Na, Cl, S
 Included as % in diet

Functions
 Structural
 Nerve
 Electrolytes
 Osmotic
balance
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
Mineral Deficiencies
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

Milk Fever Prevention

Include anionic salts in diet for 3-5 wks
prior to parturition
+ K+) – mEq(Cl- + SO4-)
 Normal diet: +20 to +30 mEq/100g diet
(electrolyte balance)
 Anionic diet: -7 to -25 mEq/100g diet
 mEq(Na+

Induces mild acidosis, which increases
tissue responsiveness to PTH
 Ca
release from bone to serum
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)
Copper, sulfur and molybdenum



High sulfur & molybdenum
thiomolybdates
Cu + thiomolybdates
insoluble complexes
Thiomolybdates can result in reduced Cu absorption and
systemic metabolism
NRC, 1996
Cu Adequate
Cu Def icient
Cu Def icient + Mn
1.8
1.6
Plasma Cu, mg/L
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
114
183
241
297
Calf day of age
422
459
490
Mineral Toxicosis
Maximum Tolerable Levels for
Ruminants
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
Copper Toxicosis Treatment
IV methylene blue to control metHb
 Copper chelators

 D-penicillamine
 Ammonium

tetrathiomolybdate
Cu:Mo ratio of 10:1 or less
Sulfur Toxicity in Ruminants
Dietary sulfate reduced to H2S (gas)
 Eructate-reinhale
 Toxic in high amounts

 Polioencephalomalacia
(PEM, brainers)
Brain lesions due to S toxicity
Polioencephalomalacia (PEM)

Terminology




Clinical signs



Polio = gray matter
Encephalo = brain
Malacia = tissue death
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
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).
60% of ruminal gas that is eructated is inhaled
Pka of HS- = 7.04
S Induced PEM
Oxidative Stress

Reactive oxygen species
 Byproduct
of cellular respiration
 Roles in cell signalling
 Dangerous in excess

Species
 Hydroxyl
 Superoxide
 Hydrogen
peroxide
Oxidative Stress

Effects
 DNA
damage
 Lipid peroxidation (oxidation of
polyunsaturated fatty acids)
 Inactivation of some enzymes (oxidation of
metal cofactors)
Antioxidant Capacity

Superoxide dismutase
 Superoxide
anion to hydrogen peroxide
 Copper-Zinc SOD-cytosol
 Manganese SOD-mitochondria
http://en.wikipedia.org/wiki/Superoxide_dismutase
Antioxidant Capacity

Catalase
 Hydrogen
peroxide to water and oxygen
 Consists of 4 parts, each containing a heme
(iron) group
Antioxidant Capacity

Glutathione peroxidase
 Hydrogen
peroxide to water
 Selenium dependent enzyme-4 selenium
atoms per molecule
Iodine

Function- part of thyroid hormone
(metabolism rate)
of body I- is in thyroid
 T4 (thyroxine)
 T3 (triiodothyronine)-3 times more active than
T4
 Controls rate of energy metabolism in cells
 70-80%
Iodine
Deficiency
 “goiter” enlarged thyroid gland

 Plants
have “goitrogens” (goiter creating),
block use of iodine
Reduced growth
 Impaired reproduction-dead, weak or
hairless young

Goiter in lamb
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)
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
Cobalt
Essential component of B12
 Required by ruminants
 Rumen microorganisms synthesize B12
from cobalt
 B12 dependent enzymes

 Methylmalonyl-CoA
mutase
 Methionine synthetase