Minerals Flashcards
What two groups are essential dietary minerals divided into and why?
Macro/major (animal needs a large quantity) and micro/trace minerals (small quantity)
List the major minerals.
Calcium, phosphorus, potassium, sodium, chlorine, sulphur and magnesium.
List the trace elements.
Iron, zinc, copper, molybdeneum, selenium, iodine, manganese and cobalt.
Why are calcium and phosphorus important?
Most important mineral constituents of bone and teeth.
What are the functions of calcium?
- Structural component of skeleton (dynamic)
- Controls cell excitability (nerve & muscle)
- Regulates muscle contraction
- Regulates blood coagulation
- Many enzyme actions
What should be the ideal ratio of Ca:P?
1:1 to 2:1
What foods supply Ca:P in an ideal ratio?
- Leafy greens
- Hay/silage
- Animal products (milk, meat, eggs)
Name a corrective source of calcium.
Limestone flour
What is a factor that can affect calcium absorption?
High fat diets –> Excess dietary free fatty acids bind Ca (& Mg) to form insoluble soaps.
What are the signs of calcium deficiency and when can it occur (mammals and hens)?
Hypocalcaemia - female mammals at the onset or peak of lactation; high calcium depends of eggshell production
What is another name of hypocalcaemia in dairy cows and what are the signs?
Milk fever - flaccid paralysis (dullness/constipation etc), recumbency, rumen stasis and pupil dilation.
What are the signs of P deficiency?
- Abnormal bone growth & osteomalacia
- Reduced growth rates
- ‘Pica’ (abnormal appetites) e.g. wood chewing
What are the functions of Mg?
- 70% total body magnesium is present in bone
- Most common enzyme activator
- Muscle contraction
- Propagation of nerve impulses
Describe body reserves of magnesium.
None & no homeostatic regulation –> dependent on dietary intake to maintain function.
Name some sources of magnesium.
All green plants (chlorophyll), meat&bone, colostrum, magnesite and calcined magnesite
What are the symptoms of hypomagnesaemia?
Grass staggers (in lactating sheep/cows) = emergency!!
Convulsions, death, hyperaesthesia
How can hypomagnesaemia occur?
a) calves fed unsupplemented all-milk diets
b) beef cattle & sheep fed on low quality roughage or fodder crops
c) lactating cattle and sheep
How can you prevent hypomagnesaemia?
- Provide shelter
- Introduce to spring grass slowly
- Use fertilisers with care
- Provide mineral (Mg) licks
- Top dress pastures
- Supplement diet/water with Mg
What are the functions of copper?
- Formation of some plasma proteins
- Essential for normal hair, wool & feather pigmentation & crimp in wool
- Essential for immune function
What stores and releases copper?
Liver
What are the signs of copper deficiency?
Anaemia, abnormal bone growth, abnormal hair/feather/wool growth, loss of hair pigmentation, CV disease
What are the signs of copper toxicity?
Jaundice, appetite loss, hepatic coma & death
Explain copper treatments in sheep.
Marked differences in copper tolerance between breeds.
Take care!! Sheep have lowest tolerance.
What is the problem with molybdenum in pastures?
Rumen microbes form sulphides which combine with Mo to form thiomolybdate –> copper thiomolybdate –> decreases Cu absorption
