Calcium, Magnesium, Phosphorus

Ca Absorption

Duodeum and ileum, active and passive transport, dietary Ca conc makes less Ca absorbed

Ca in Tissues

Bones and teeth, blood plasma

Ca to P ratio

2:1

Ca Functions in Skeletal Structure

Continual turnover and remodeling, ossification

Ca Function in Cellular Metabolism

Excitablility of nerve and muscle, neurotransmitter synthesis

Calcium Excretion

Sweat, urine, feces

Signs of Defiency

Rickets/osteomalacia, fibrous osteodystrophy, adverse effects on repro and lactation

Milk fever

Deficiency of Ca, occurs early in lactation, incoordination, loss of appetite, nervousness

Calcium toxicity

Osteopetrosis, calcification of soft tissues, urinary calculi, altered absorption of other minerals

Phosphorus Absorption

Active and passive transport, incorporated into phospholipids, impacted by phytate P

Phosphorus Tissue Distribution

80% in skeleton, in blood serum

Phosphorus Functions

Skeletal structure, phospholipids, component of RNA/DNA/AMP/ADT/ATP

Phosphorus excretion

Loss from feces, saliva, urine*

Phosphorus Deficiency

Rockets, pica, high Ca levels, loss of appetite

Phosphorus Toxicity

Fibrous osteodystrophy, softening ribs, suffocation, laxative effect, inhibits Ca absorption

Magnesium absorption

Ileum, no active transport

Magnesium Tissue Distribution

3rd most common mineral, bone, soft tissues

Magnesium Metabolism

Excretion in urine and feces, control not understood

Magnesium Functions

Skeletal development, assists with oxidative phosphorylation in heart mitochondria, enzymes, cofactor for enzymes

Magnesium deficiency

Anorexia, muscle twitching, death, calcification and necrosis of kidney

Grass tetany

High K and protein contribute, interferes with tca cycle

Mg Toxicity

Depressed feed intake, diarrhea, loss of reflexes, low blood pressure, heart stops