Week 5: Mineral Nutrition (Principles and Ca nutrition)

Question 1

What bodily functions do minerals support?

Answer 1

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

Question 2

Where are minerals stored?

Answer 2

Minerals are held in different compartments.

They have a central reserve plus one or more reserves.

Question 3

Most minerals have a catalytic function.

What does catalysis mean?

Answer 3

Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance

Question 4

Minerals can occur as three absorption rates which are?

Answer 4

• Easily absorbed
• Partially absorbed
• Not absorbed

Question 5

Minerals can be converted between different forms which is dependent on what?

Answer 5

pH

Question 6

What are some examples of mineral availability?

Answer 6

• P often present as phytic acid(need phytases to access)
• Availability in milk higher than solid food
• Chelated minerals (protective coating, enzymes can change chelation and make it available through digestion)

Question 7

What is the most abundant mineral in the body?

Answer 7

Calcium Ca

Question 8

What is Ca essential for?

Answer 8

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

Question 9

What is the blood calcium homeostasis level?

Answer 9

80-120 mg/L

Question 10

What are good sources for Ca?

Answer 10

• milk
• legumes
• animal prouducts containing bone
• grains low
• limestone

Question 11

What happens when there is excessive Phosphoros P?

Answer 11

P binds to Ca, reducing Ca absorption

Question 12

What happens if there is deficiency of vit D?

Answer 12

Prevents proper Ca utilisation

Question 13

What is the recommended Ca:P ratio?

Answer 13

Between 1:1 and 2:1

Question 14

What are the two forms of Vit D?

Answer 14

• Vit D2 (ergocalciferol)
  - ergosterol precurser
• Vit D3 (cholecalciferol)
  - 7-dehydrocholestrol precursor

Question 15

Where is Vit D found?

Answer 15

Cut forages

Question 16

Where is Vit D produced?

Answer 16

In the skin by exposure to UV light

Question 17

Where is Vit D stored?

Answer 17

Liver - sits there until required

Question 18

What happens when Vit D works with the Parathyroid Hormone (PTH)?

Answer 18

Maintains plasma Ca concentration through resorption and absorption

Question 19

What are some effects of Ca deficiency and excess P?

Answer 19

• Rickets
• Developmental orthopaedic disease
• Osteomalacia
• Brittle bone
• Hyperparathyroidism
• Milk fever

Question 20

What is Hypocalcaemia and what are the symptoms?

Answer 20

MILK FEVER

• Inappetence
• Lateral recumbancy
• Coma and death
• Plasma [Ca]

Question 21

What causes hypocalcaemia?

Answer 21

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

Question 22

Where is Ca absorbed from?

Answer 22

The gut when needed. The efficiency declines as diet Ca increases

Question 23

How much Potassium K can be found in pastures?

Answer 23

4 - 5 % depends on fertiliser and can peak in winter

Question 24

What does K help retain?

Answer 24

Plasma Ca but decreases loss of Ca through urine

Question 25

What happens with excess K?

Answer 25

Causes metabolic alkalosis Can reduce Mg plasma

Question 26

What can alter Ca homeostasis?

Answer 26

Hypomagnesaemia - less able to mobilise Ca from bone

Question 27

How much Mg Magnesium is needed in the diet?

Answer 27

0.2-0.4% and is poorly absorbed

Question 28

What can high P cause?

Answer 28

Increased mobilisation of Ca from bone regardless of Ca in the diet. Induce hypocalcemia (inhibits PTH action on renal tissue)

Question 29

What is DCAD?

Answer 29

Dietary Cation-Anion DIfference

Question 30

What happens when you lower DCAD?

Answer 30

Reduces blood and urine pH which improves Ca homeostasis

Question 31

Which mineral has the most known functions

Answer 31

P

Question 32

Where is P concentrated?

Answer 32

Bone

Question 33

What is P essential for?

Answer 33

- bone development - nucleic acids, phospholipids, phosphoproteins - energy metaboloism (ATP) - buffers

Question 34

What are good P sources?

Answer 34

- milk - cereal grains (often unavailable form) - animal products containing bone - hays and straws low

Question 35

What happens with P deficiency?

Answer 35

- similar bone disorders to Ca - lameness, bone and wood cheweing - low fertility - poor growth

Question 36

Magnesium is a what activator?

Answer 36

Enzyme

Question 37

What does Mg control?

Answer 37

Nerve impulses

Question 38

Where is Mg mostly absorbed in monogastrics?

Answer 38

Lower half of SI

Question 39

What are some Mg definency symptoms?

Answer 39

Hypomagnesemia (grass tetany) - common in ruminants - rare in monogastrics Tetany results in nervousness, muscle tremors, excessive sweating, rapid breathing, convulsions, loss of appetite

Question 40

What are some good sources of Mg?

Answer 40

- legumes - wheat bran - Mg blocks - Magnesium Oxide - magnesium sulfate or chloride in troughs

Question 41

What can Mg availability be affected by?

Answer 41

- Low content in feed - lower in pastures than conserved feeds - K content of pastures (reduces plant uptake of Mg and absorption) - High rumen Digestible Nitrogen in plants - Genetics

Question 42

What does Sodium do?

Answer 42

- body fluid reg - acid base balance - muscle and nerve activity - exercising, lactating and animals with diarrhoea need more - most feeds are low in Na

Question 43

What does Chlorine do?

Answer 43

- acid base relationships - osmotic reg - gastric secretion - deficiency can cause alkalosis

Question 44

What does Potassium do?

Answer 44

- osmotic reg and acid base balance - muscle and nerve function - CHO metabolism