Minerals

Question 1

What are the main functions of minerals?

Answer 1

1. constituents of skeleton structures
2. maintenance of osmotic pressure
3. regulation of acid base balance
4. components of enzymes
5. activators of enzymes
6. components of biological units

Question 2

What are the main functions of minerals?

Answer 2

1. constituents of skeleton structures
2. maintenance of osmotic pressure
3. regulation of acid base balance
4. components of enzymes
5. activators of enzymes
6. components of biological units

Question 3

What are the macro-minerals?

Answer 3

> 5g in body

Ca, P, Mg, K, Na, Cl, S

Question 4

Which minerals are concentrated by plants and why?

Answer 4

Cu, Zn, Fe, Mn, Mb

- mineral by products from industry and manufacturing

Question 5

Which minerals are concentrated by plants and why?

Answer 5

Cu, Zn, Fe, Mn, Mb

- mineral by products from industry and manufacturing

Question 6

What minerals are involved in bone metabolism

Answer 6

The most important role of minerals in the horse’s diet is the development in mineralized tissues

Bone in metabolically active tissue and requires:

• supply of Ca and P
• other minerals - F, Mg, Mn, Zn
• osteoblasts, osteoclasts
• calcitonin, parathyroid hormons

Question 7

What are the micro- minerals

Question 8

Which minerals are concentrated by plants and why?

Answer 8

Cu, Zn, Fe, Mn, Mb

- mineral by products from industry and manufacturing

Question 9

Relationship between dietary levels and absorptive efficiency

Answer 9

absorptive efficiency tends to decrease when intake increases

Question 10

What minerals are involved in bone metabolism

Answer 10

The most important role of minerals in the horse’s diet is the development in mineralized tissues

Bone in metabolically active tissue and requires:

• supply of Ca and P
• other minerals - F, Mg, Mn, Zn
• osteoblasts, osteoclasts
• calcitonin, parathyroid hormons

Question 11

What happens to bone resorption during times of physiological stress?

Answer 11

The skeleton maintains structural integrity and regulates calcium homeostasis –> bone can be resorbed and remodelled

Question 12

What are the functions of calcium?

Answer 12

Structural function - bone crystals = hydroxyapatite
- 99% in bone/teeth
= 1% found in soft tissues where it is involved in muscular activity, blood clotting, hormone secretion and enzyme activation
- Ca:P in bone = 2:1

Question 13

What is the result of calcium deficiency?

Answer 13

Although horses are good at recognizing some deficiencies (Na) they are not good at recognizing Ca

• rickets
• osteomalacia (in mature animals)
• nutritional secondary hyperparathyroidism
• lactating mares –> decrease milk production (but Ca and P remain the same)

Question 14

What hormone regulates calcium concentrations?

Answer 14

PTH

• maintains calcium homeostasis in blood
• mediated by vitamin D (calcitriol)
• PTH + calcitriol act on the bone and kidneys to maintain plasma Ca levels

low Ca –> parathyroid –> calcitriol –> Ca binding protein –> Ca reabsorption + absorption

Question 15

Where does Ca absorption occur?

Answer 15

small intestine

- passive and facilitated diffusion

Question 16

Ca absorption efficiency varies with:

Answer 16

• age (70% in young, 50% in mature)
• diet (low Ca increases absorption; high P binds Ca)
• stage of training
• stages of gestation/lactation

Question 17

What is the result of calcium deficiency?

Answer 17

Although horses are good at recognizing some deficiencies (Na) they are not good at recognizing Ca

• rickets
• osteomalacia (in mature animals)
• nutritional secondary hyperparathyroidism

Question 18

What is rickets?

Answer 18

• failure of vascular invasion and mineralization in the area of calcification of the physis
• bone pain, stiff gait, swelling in the area of the metaphyses, difficulty rising, bowed limbs, pathologic fractures

Question 19

What is nutritional secondary hyperparathyroidism?

Answer 19

AKA Miller’s Disease, Bran Disease or Big Head Syndrome

• results from excess P
• lameness
• enlarged facial bone –> fibrous connective tissue invades area where bone was resorbed
• P binds to Ca –> Ca from bone is resorbed to compensate for deficiency

Question 20

Calcium toxicity

Answer 20

• high dietary Ca levels interfere with absorption of other minerals (e.g. P, Mg, Mn, Zn)
• brittle bones
• horses can handle high calcium levels (up to 7:1)

Question 21

What are calcium requirements dependent on?

Answer 21

• vitamin D supply
• phosphorus supply
• rate of growth
• physiological state
• presence of oxalic acid and physics acid

Question 22

P deficiency

Answer 22

Similar to Ca and vitamin D

- occurs when P is in an unavailable form (phytic acid or phytate)

Question 23

Sources of Ca

Answer 23

• animal sources (e.g. meat meal)
• milk
• grains low
• roughages borderline
• concentrates and complete rations should be balanced and supply = 2:1

Question 24

What are the functions of P?

Answer 24

• major constituent of bone (14-17% skeleton)
• required for many energy transfer reactions
• synthesis of phospholipids, nucleic acids, phospho-proteins

Question 25

When is P very important?

Answer 25

reproduction, gestation, lactation

Question 26

P deficiency

Answer 26

Similar to Ca and vitamin D | - occurs when P is in an unavailable form (phytic acid or phytate)

Question 27

Ca levels and exercise

Answer 27

Exercise --> change in extracellular concentrations | - Increased Ca can help

Question 28

Functions of Na

Answer 28

Found in mainly extracellular fluid and small amounts found in skeleton - acid base balance - osmotic pressure - absorption of CHO and AA

Question 29

What is the result of sodium chloride deficiency?

Answer 29

- poor growth (decreased feed intake) - reduction in utilization of CHO and protein - PICA appetite (horses will eat ANYTHING to obtain salt; very sensitive to salt)

Question 30

Where are Na and Cl absorbed?

Answer 30

small intestine - excreted via sweat & urine - 0.5-1% diet

Question 31

benefits to providing salt block

Answer 31

- easy to provide - stimulates salivation - no danger for over-consumption - horses may have difficulty obtaining enough - must provide adequate water (stimulates drinking)

Question 32

How does the body compensate when dietary sodium is low?

Answer 32

- decrease in urine & sweat production --> could compromise performance an water balance) - can resorbs from kidneys or see it (lick themselves, saddle pads, eat dirt)

Question 33

What is the result of sodium chloride deficiency?

Answer 33

- poor growth (decreased feed intake) - reduction in utilization of CHO and protein - PICA appetite (horses will eat ANYTHING to obtain salt; very sensitive to salt)

Question 34

Where can a lot of iodine be found?

Answer 34

75% in the thyroid | - component of thyroxine which helps control basal metabolic rate

Question 35

What is hyperthyroidism?

Answer 35

reduced thyroxine --> drop in BMR --> weight gain

Question 36

What does a deficiency in iodine lead to?

Answer 36

A decrease in the production of thyroxine - foals born with goiter - foals can be stillborn, or weak & hairless - when mares are grazing on iodine deficient soil --> should be given iodized salt blocks

Question 37

Iodine toxicity

Answer 37

Horses are very sensitive (can tolerate levels of 5 ppm vs. other species 200-600 ppm)

Question 38

Why is it important to consider Se levels

Answer 38

soils low in Se --> white muscle disease | soils high in Se --> can result in toxicity = alkali disease or blind staggers

Question 39

Deficiency of iron?

Answer 39

- decrease in # of RBCs | - may occur in horses that are heavily parasitized due to bleeding after worming

Question 40

Why do horses have higher requirements for iron than adults?

Answer 40

- milk is a poor source of iron | - provide creep feeds that allow foal access but prevents mares

Question 41

What is the function of selenium?

Answer 41

- closely related to that of vitamin E and other antioxidants

Question 42

Why is it important to consider Se levels

Answer 42

soils low in Se --> white muscle disease | soils high in Se --> can result in toxicity = alkali disease or blind staggers

Question 43

Functions of zinc

Answer 43

- found in hair, skin, bone - acts as enzyme activator or is a component of an enzyme (specifically enzymes involved in keratinization) - Zn is a cofactor for over 200 reactions - often works in combination with B-carotene

Question 44

Zinc deficiency

Answer 44

poor skin, hair

Question 45

Functions of Mg

Answer 45

- constituent of bone and teeth - enzyme activator - depends on levels of Ca, P, Zn in diet (BALANCE minerals) - increased Ca and P will decrease digestibility of Mg

Question 46

Mg deficiencies

Answer 46

- nervous system disorders, hyper irritability, tetany (often precipitated by stress) - grass tetany = rare but can occur on fast growing pasture, in lactating mares or horses in transit or fasting (high stress) - nervousness, tremors, staggering, convulsions, death Mg is calming

Question 47

Functions of copper

Answer 47

- involved in synthesis of Hb - involved in bone formation - oxidation-reduction enzyme systems

Question 48

Deficiency of Cu

Answer 48

anemia (Hb) or thin weak bones

Question 49

Cu toxicity

Answer 49

not seen in horses

Question 50

Which minerals are significantly involved in bone maintenance, structure, or formation?

Answer 50

Ca, P, Cu, Zn, Mg

Question 51

Why could a deficiency in salt result in poor growth or performance?

Answer 51

Na+ is needed for the absorption of carbohydrates and amino acids, as Na+ dependent transporters in the small intestine are responsible for absorbing these nutrients.