Macrominerals

1
Macrominerals
Pages 3637 in textbook
2
Macro-Mineral Supplementation
3
Calcium Sources

• Minerals
• Limestone, dicalcium phosphate
• Animal sources
• Meat and bone meal, fish meal
• Milk products
• Roughages
• But not cereal grains

4
Calcium

• Most abundant mineral in animal tissues
• Lots of functions
• Bone structure
• Nerve function
• Blood clotting
• Muscle contraction
• Cellular metabolism

5
Calcium (Ca)

• Functions
• Bone/teeth formation and maintenance
• 99 of body calcium
• In 21 ratio with phosphorus in hydroxyapatite
  Ca5(PO4)3OH
• Soft tissues
• Enzyme activation
• Blood clotting
• Muscle contraction
• Transmission of nerveimpulses to muscle
• Calcium binds to troponin C

6
Calcium Absorption

• From duodenum and jejunum
• Active or passive
• Dependent on vitamin D stimulates calbindin in
  small intestinal cells and enhances absorption
• Absorption depends on need
• Particularly high during growth, pregnancy and
  lactation
• Bioavailability decreased by
• Phytates (grains)
• Wheat bran
• Low estrogen levels (postmenopausal women)
• High fat diets (form soaps with fatty acids)

7
Calcium (Ca)

• Dietary ratio of 11 to 21 ideal for most
  animals (except for laying hen, optimal ratio is
  131 Canonphytate phosphorous)
• Never want P gt Ca

Grains tend to be low in calcium while forages
are moderate to high
8
Calcium Regulation

• Three hormones involved in regulation
• Vitamin D3
• from kidney
• Parathyroid hormone (PTH)
• from parathyroid gland
• Calcitonin
• from thyroid gland
• PTH and vitamin D3 act to increase plasma Ca,
  while calcitonin acts to decrease plasma Ca

9
GI Tract
Dietary Ca
Fecal Ca
Endogenous Ca
Absorbed Ca

1,25(OH)2D3 from kidney
Blood Ca
Sweat Ca
Urinary Ca
-

Ca Apposition
Ca Resorption
PTH
Calcitonin
Plasma Ca
Parathyroid Gland
Bone Ca
Plasma Ca
10
Calcium Deficiency - Causes

• Low calcium intake or absorption
• Soap formation (fatty acids) in rumen
• Competition with divalent ions for absorption
• Abnormal CaP ratio (21)
• High calcium and low phosphorus leads to
  formation of insoluble CaPO4 in intestinal lumen
• High phosphorus (and low calcium) also inhibits
  absorption
• Vitamin D deficiency

11
Calcium Deficiency - Symptoms

• Reduced growth or production rate
• Egg-shell strength
• Rickets
• Young, fast-growing animals
• Misshapen bones, enlarged joints, lameness
• Osteoporosis
• Decalcification of bone and loss of bone mass
• Estrogen involved, bone mass decreases following
  menopause
• Isoflavones (estrogen-like compounds) in soy help
  alleviate losses

12
(No Transcript)
13
Osteoporosis

• Decrease bone mass
• Related to aging, poor diet, and estrogen loss
• Leads to 1.5 million bone fractures per year
• Slender, inactive women who smoke are at highest
  risk
• Type I (postmenopausal)
• Type II (senile)

14
Bone Strength

• Depends on bone mass
• Related to age, gender, activity level and
  genetics
• Peak bone mass in women achieved by age 20-30
• Same in females of all mammalian species peak
  mass achieved as animal reaches maturity and then
  decreases thereafter
• Cannot increase bone density after this point,
  but can slow rate of bone density loss
• By age 65, some women have lost 50 of bone mass

15
Calcium Deficiencies

• Rickets
• in growing animals
• Osteomalacia and osteoporosis
• in adult animals
• Milk fever (parturient paresis)
• in lactating animals

16
Calcium Deficiency Milk Fever

• High demand for milk calcium during early
  lactation calcium pulled from blood
• Cannot absorb enough calcium from gut or reorb
  from bone rapidly enough to keep up
• Severe hypocalcemia (low blood calcium) results
• Factors associated
• Parturition
• Onset of lactation
• Breed
• Age
• Diet

17
Hypocalcemiaat Parturition
Plasma calcium
PTH
1,25(OH)2D3
Absorption from GI tract
Absorption from kidney
Plasma calcium increased
Resorption from bone
18
Milk Fever

• Symptoms
• Listless
• Staggers or weaves when walks
• Lies down in characteristic pose
• head retraction
• Decreased plasma calcium

19
Milk Fever

• Treatment
• IV calcium solution
• Oral calcium gels
• Prevention options
• Dietary acidbase balance, not calcium level
• Alter dietary cation-anion balance
• Feed anion salts or adjust dietary potassium
• Increased calcium release from bones and
  increased calcium absorption from diet
• Mediated through parathyroid hormone

20
Phosphorus Sources

• Minerals
• Dicalcium phosphate
• Monocalcium phosphate
• Deflourinated rock phosphate
• Animal sources
• Meat and bone meal
• Fish meal
• Cereals
• Large portion of phosphorus unavailable for
  non-ruminants
• Phytic acid (poorly absorbed)

21
Phosphorus (P)

• Functions
• Component of bones/teeth
• 80 in bone (hydroxyapatite)
• 20 in soft tissue
• Membrane phospholipids, DNA, RNA
• Similar to calcium
• Vitally important in energy metabolism
• ATP and creatine phosphate
• Sugar phosphates
• Acid-base balance (HPO4)
• Regulation of metabolism
• Glucose-6-phosphate
• Phosphorylation activates or inactivates enzymes

22
Phosphorus (P)

• Absorption
• Both active and passive mechanisms
• High phosphorus limits calcium absorption
• Plant phosphorus often unavailable to animal
• Phytic acid
• Released by phytase (enzyme often supplemented)
• Blood levels controlled by vitamin D and
  parathyroid hormone

23
Phosphorus Deficiency

• Deficiency
• Symptoms similar to calcium deficiency
• Reduced growth or production rate
• Rickets or osteomalacia
• Pica (depraved appetite) chewing of wood
  fences, bones, soil
• Low fertility and poor milk production or growth

24
Phosphorous

• Impact on environment has scientists revisiting
  nutritional requirements
• Requirements are being lowered without any
  negative effects on reproduction or milk
  production
• Bioavailability could be improved if phytate
  phosphorus can be reduced
• Increasing availability would reduce dietary
  requirements and fecal excretion

25
Magnesium Sources

• Mineral sources
• MgCO3, MgCl2, MgO (mag-ox)
• MgSO4
• a.k.a. Epsom salts, milk of magnesia

26
Magnesium (Mg)

• Functions
• Bone formation
• 60 in bone
• Enzyme activation
• Carbohydrate, lipid metabolism
• 7 enzymes in glycolysis require magnesium as a
  cofactor
• Urea cycle
• Binds mRNA to ribosomes
• Associated with ATP metabolism
• ATPMg2 complex

27
Magnesium and Muscle Function

• Magnesium required for energy releasing enzyme
  activity in skeletal muscle
• ATP needed for detachment and calcium uptake
• Calcium is the link between excitation and
  contraction
• Lack of ATP to return calcium to storage results
  in tetany

28
Magnesium

• Deficiency
• Vasodilation
• Results in reduced blood pressure
• Hyperirritability, convulsions
• Anorexia, reduced weight gain
• Hyperemia
• Hypomagnesemic tetany (grass tetany)
• Early lactating cows on grass
• Poor nervous and muscular control
• Usually not an issue, adequate levels present in
  most diets

29
Magnesium Deficiency Grass Tetany

• Also called grass staggers, hypomagnesemia
• Low blood magnesium
• Symptoms
• Nervousness
• Tremors, twitching of face muscles
• Staggering gait or convulsions
• Etiology not completely understood

30
Grass Tetany

• Spring pastures, lush grasses
• Low magnesium content
• Some magnesium absorption in rumen
• Requires relatively low pH
• High potassium forages raise rumen pH and impedes
  Mg absorption
• Potassium alters acid-base balance (cation
  induces alkaline environment)
• Pasture contains organic acids that bind
  magnesium
• Solution
• Dust pasture with MgO
• Feed 111 magnesium oxideTM saltgrain
  starting 2 weeks before turning ruminants out on
  pasture

31
Sodium and Chloride Sources

• Minerals
• Salt (iodized, 0.007 iodine added)
• Add at 0.250.50 of diet
• Free-choice salt blocks
• May be combined with other minerals
• Animal sources
• Meat and bone meal, meat meal
• Fish meals may have a (very) high salt content
• Cereal grains
• Low sodium and choride content

32
Sodium (Na) and Chloride (Cl)

• Functions
• Electrolytes
• Absorption of glucose and amino acids
• Transmission of nerve impulses
• Action potential
• Osmotic pressure balance
• 10 sodium and chloride intracellular, 90
  extracellular
• Sodium is main extracellular cation
• Maintained by Na/K ATPase
• Chloride is main extracellular anion
• HCl and chloride salts in gastric secretions

33
Sodium and Chloride

• Blood concentrations highly regulated
• Excess intake increased excretion
• Little danger of toxicity if water available
• NaCl added to diets to increase palatability
• Causes of deficiencies
• Lactation
• Sodium and chloride secreted in milk
• Rapid growth
• On a diet of cereals or forages
• High temperatures or hard work
• Sweat

34
Symptoms of Sodium and Chloride Deficiency

• Decreased osmotic pressure
• Leads to weakness
• Circulatory failure
• Metabolic alkalosis (decreased chloride) or
  acidosis (decreased sodium)
• Poor growth
• Reduced appetite and feed consumption
• Reduced carbohydrate and amino acid absorption
• Diminished HCl secretion from parietal cells
• Reduced bacterial defense and protein digestion
• Pica or salt craving
• Animals will seek out salt sources
• Soil, urine, sweat of other animals, etc.

35
Pica

• Animals do not necessarily seek out sources of
  the mineral that is deficient in diet just
  consume non-feed items
• Coprophagia (consumption of excrement)
• Geophagy (consumption of soil, clay, or chalk)
• Consumption of dust or sand in iron deficient
  patients.
• Vampirism (ingestion of blood)
• Hyalophagia (consumption of glass)
• Pagophagia (pathological consumption of ice)
• Self-cannibalism (rare condition where body parts
  may be consumed sometimes called Lesch-Nyhan
  syndrome)
• Trichophagia (consumption of hair or wool)
• Urophagia (consumption of urine)
• Xylophagia (consumption of wood)
• Cautopyreiophagia (consumption of burnt matches)

36
Sodium and Health

• High blood sodium is associated with high blood
  pressure and risk of heart disease
• However, high blood sodium rarely due to dietary
  excesses
• Genetics is primary factor, although other
  factors are involved
• 10-15 of adults are salt-sensitive and should
  limit salt intake

37
Potassium Sources

• Plants generally have a high potassium content
• Grains 0.30.8
• Vegetable proteins 1.02.5
• Alfalfa 2 or more
• Implications for dairy in developing anionic
  diets for preventing milk fever!!
• Animal products vary

38
Potassium

• Functions
• Third-most abundant mineral in the body
• 2/3 of whole-body potassium content in skin and
  muscles
• gt95 of potassium intracellular (major
  intracellular cation)
• Maintained by Na/K ATPase
• Regulation of osmotic and acid-base balance
• Transmission of nerve impulses
• Potassium is the major determinant of the resting
  membrane potential of all cells
• Cofactor for several reactions in carbohydrate
  metabolism

39
Potassium Deficiency

• Rare
• Has to be induced
• Major salt in ruminant sweat
• Increases requirement in heat stress
• Reduced appetite and growth
• Other symptoms
• Tetany, nervous disorders
• Degeneration of organs
• Abnormal heart function

40
Sulfur (S)

• Located in organic compounds
• Thiamin biotin methionine, cystine and
  cysteine
• Chondroitin sulfate matrix of cartilage
• Feathers, wool, etc.
• Wool contains about 4 sulfur
• Minimal involvement in acid-base balance
• Ideal NS ratio of 101 in ruminant diets
• Potential for toxicity