Minerals

Question 1

What two groups are essential dietary minerals divided into and why?

Answer 1

Macro/major (animal needs a large quantity) and micro/trace minerals (small quantity)

Question 2

List the major minerals.

Answer 2

Calcium, phosphorus, potassium, sodium, chlorine, sulphur and magnesium.

Question 3

List the trace elements.

Answer 3

Iron, zinc, copper, molybdeneum, selenium, iodine, manganese and cobalt.

Question 4

Why are calcium and phosphorus important?

Answer 4

Most important mineral constituents of bone and teeth.

Question 5

What are the functions of calcium?

Answer 5

• Structural component of skeleton (dynamic)
• Controls cell excitability (nerve & muscle)
• Regulates muscle contraction
• Regulates blood coagulation
• Many enzyme actions

Question 6

What should be the ideal ratio of Ca:P?

Answer 6

1:1 to 2:1

Question 7

What foods supply Ca:P in an ideal ratio?

Answer 7

• Leafy greens
• Hay/silage
• Animal products (milk, meat, eggs)

Question 8

Name a corrective source of calcium.

Answer 8

Limestone flour

Question 9

What is a factor that can affect calcium absorption?

Answer 9

High fat diets –> Excess dietary free fatty acids bind Ca (& Mg) to form insoluble soaps.

Question 10

What are the signs of calcium deficiency and when can it occur (mammals and hens)?

Answer 10

Hypocalcaemia - female mammals at the onset or peak of lactation; high calcium depends of eggshell production

Question 11

What is another name of hypocalcaemia in dairy cows and what are the signs?

Answer 11

Milk fever - flaccid paralysis (dullness/constipation etc), recumbency, rumen stasis and pupil dilation.

Question 12

What are the signs of P deficiency?

Answer 12

• Abnormal bone growth & osteomalacia
• Reduced growth rates
• ‘Pica’ (abnormal appetites) e.g. wood chewing

Question 13

What are the functions of Mg?

Answer 13

• 70% total body magnesium is present in bone
• Most common enzyme activator
• Muscle contraction
• Propagation of nerve impulses

Question 14

Describe body reserves of magnesium.

Answer 14

None & no homeostatic regulation –> dependent on dietary intake to maintain function.

Question 15

Name some sources of magnesium.

Answer 15

All green plants (chlorophyll), meat&bone, colostrum, magnesite and calcined magnesite

Question 16

What are the symptoms of hypomagnesaemia?

Answer 16

Grass staggers (in lactating sheep/cows) = emergency!!
Convulsions, death, hyperaesthesia

Question 17

How can hypomagnesaemia occur?

Answer 17

a) calves fed unsupplemented all-milk diets
b) beef cattle & sheep fed on low quality roughage or fodder crops
c) lactating cattle and sheep

Question 18

How can you prevent hypomagnesaemia?

Answer 18

1. Provide shelter
2. Introduce to spring grass slowly
3. Use fertilisers with care
4. Provide mineral (Mg) licks
5. Top dress pastures
6. Supplement diet/water with Mg

Question 19

What are the functions of copper?

Answer 19

1. Formation of some plasma proteins
2. Essential for normal hair, wool & feather pigmentation & crimp in wool
3. Essential for immune function

Question 20

What stores and releases copper?

Answer 20

Liver

Question 21

What are the signs of copper deficiency?

Answer 21

Anaemia, abnormal bone growth, abnormal hair/feather/wool growth, loss of hair pigmentation, CV disease

Question 22

What are the signs of copper toxicity?

Answer 22

Jaundice, appetite loss, hepatic coma & death

Question 23

Explain copper treatments in sheep.

Answer 23

Marked differences in copper tolerance between breeds.
Take care!! Sheep have lowest tolerance.

Question 24

What is the problem with molybdenum in pastures?

Answer 24

Rumen microbes form sulphides which combine with Mo to form thiomolybdate –> copper thiomolybdate –> decreases Cu absorption