Mineral Nutrition- Principles and Ca nutrition

Question 1

Name some functions of mineral nutrition (6)

Answer 1

structural
enzymes/cofactors
regulating osmotic pressure
pH
nerve and muscle function
vitamin, blood cell and hormone synthesis

Question 2

State 3 reasons why an animal might be deficient in minerals..

Answer 2

insufficient mineral in diet
low absorption
Mineral interactions

Question 3

In digesta, minerals occur as: (3)

Answer 3

1) Metallic ions in solution (easily absorbed, eg Na+ and K+)
2) Constituents of metallo-organic substances (some absorbed, eg chelated)
3) Parts of insoluble substances (not absorbed)

Question 4

Which is the most abundant mineral in the body?

Answer 4

Ca is the most abundant mineral in body, concentrated in bone

Question 5

List 3 things that Ca is essential for in the body

Answer 5

bone and teeth development
enzyme systems for normal muscle and nerve function
blood clotting

Question 6

List some sources of Ca (5)….

Answer 6

Milk
green, leafy crops (legumes)
animal products containing bone
grains low
limestone

Question 7

Recommended Ca:P ratio??

Answer 7

between 1:1 to 2:1

Question 8

Excessive P binds Ca reducing Ca absorption… True/ False?

Answer 8

True

Question 9

Deficiency of vitamin D prevents proper Ca utilisation.. True/ False?

Answer 9

True

Question 10

How is vitamin D synthesised?

Answer 10

Produced in skin by exposure to UV light

Question 11

Where is Vit D stored?

Answer 11

Stored in liver

Question 12

Good sources of Vit D?

Answer 12

Sunlight and sun-cured forages good sources

Question 13

List some effects of Ca deficiency / P excess.. E.g. Rickets (5)

Answer 13

Young animals – rickets
Young growing horses – DOD
Osteomalacia in older animals
brittle bone (osteoporosis in older animals)
Milk fever

Question 14

What is milk fever?

Answer 14

Clinical hypocalcaemia (milk fever or parturient paresis/paralysis)

Question 15

List 3 symptoms of milk fever

Answer 15

Inappetence
Lateral recumbency
Coma and death

Question 16

What is the most common mineral-related problem of the transition cow

Answer 16

hypocalcaemia (milk fever)

Question 17

What causes hypocalcaemia?

Answer 17

Inability to absorb from gut and mobilise from bone enough Ca to meet sudden demand imposed on plasma Ca pool by lactogenesis

Question 18

Excess K causes metabolic alkalosis.. How?

Answer 18

Reduces sensitivity of bone and renal tissue to PTH

Prevents up-regulation of 1, α-hydroxylase

Question 19

Can hypomagnesaemia alter Ca homeostasis?

Answer 19

YES

Question 20

How can hypomagnesaemia alter Ca homeostasis?

Answer 20

Less able to mobilise Ca- PTH and calcitriol secretion and activity retarded

Question 21

Name one mineral that can alter plasma Mg

Answer 21

High dietary K can reduce plasma [Mg]

Question 22

Can an excess of P induce hypocalcaemia?

Answer 22

Yes

Question 23

How can an excess of P induce hypocalcaemia?

Answer 23

Inhibits PTH action on renal tissue

Question 24

Apart from K, what other mineral has the potential to cause metabolic alkalosis?

Answer 24

Sodium, although most diets are low

Question 25

List 2 dietary options for reducing milk fever..

Answer 25

Manipulating dietary cation-anion difference (DCAD) (feeding anionic salts) Replenishing Ca reserves

Question 26

Does lowering DCAD increase or reduce blood (and urine) pH?

Answer 26

It reduces blood and urine pH.

Question 27

What effect does lowering DCAD have on Ca homeostasis?

Answer 27

Lowering DCAD reduces blood and urine pH, thus improving Ca homeostasis.

Question 28

Should DCAD be positive or negative to protect against Milk Fever?

Answer 28

Negative

Question 29

What can be used to assess DCAD?

Answer 29

Urine pH an indicator (6-7)

Question 30

What is osteopetrosis?

Answer 30

Excess bone mass

Question 31

Can excess Ca reduce absorption of Mn, Fe, Zn and Cu and P

Answer 31

Yes