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Flashcards in FSE Revision Deck (85)
1

Macrominerals

List the macrominerals

• Ca

• P

• K

• Na

• Mg

• Cl

2

Macrominerals

What are macrominerals?

-describe

Required in large amounts
• Accumulation can be toxic

• Storage variable
    - Some good e.g. Ca
     – Bone  Some poor e.g. Mg
    – intracellular fluid of cells

• Multiple functions
    -Enzymatic

     -Fertility – e.g. P
     -Development – e.g. Ca
     - Transport – e.g. Na, K & Cl  More

3

Macrominerals

How do deficiencies occur?

Insufficient mineral in diet

• Low absorption - Bioactivity

• Mineral interaction

- Form unabsorbable compounds - Compete for transport systems (facilitated transport)

• Feed composition tables don’t give availability

- P often as phytic acid requiring phytases to access  Mg oxalate less absorbable than Mg sulfate

4

Macrominerals

What is Ca needed for?

Essential for bone & teeth development

• Enzyme systems

• Nerve & muscle function

• Blood clotting

• Heavily regulated in the blood (homeostasis - ~80 to 120 mg/L)
- Hormonal regulation

- Parathyroid hormone (PTH)

- Vitamin D (feed small, sunlight high)

- Regulate Ca intake and reabsorption from bones

• P binds Ca

- Reduce Ca absorption

- Ca to P ratio between 1:1 and 2:1

5

Vitamin D

-what is it needed for?

-where is it found?

Found in cut forages - hay

 Exposure to UV light

 Two forms – D2 and D3

 Stimulated production by PTH to increase mobilisation of Ca from bones & absorption from intestines

 Deficient animals usually housed indoors and little forage fed

6

Describe diseases that result due to Ca deficiency

Young, growing animals – Rickets & Developmental Orthopaedic Disease

 Older animals - Osteoporosis

 Early lactating animals – e.g. Dairy cow (Hypocalcaemia - milk fever)

7

Macrominerals

What is Mg needed for?

Required for enzyme function, nerve & muscle function, protein synthesis, blood glucose control, energy production, etc.

• Poorly stored

• Very small quantities within the interstitial fluid of the cells

• Low blood concentration

-  Heavily regulated

• 0.2 to 0.4% Mg needed in diet

• Mg poorly absorbed

• High dietary K can reduce plasma concentration of Mg

-  Decrease absorption from SI

• Hypomagnesaemia reduces blood Ca concentrations
-  Can cause milk fever

-  Less able to mobilise Ca from bones

8

Macrominerals

What is Hypomagnesaemia?

What are the clinical signs?

 Grass tetany

 Common in ruminants, not horses

 Late winter-early spring (low Mg in feed)

• Clinical signs

 Nervousness

 Muscle tremor

 Excessive sweating

 Rapid breathing

 Convulsions

 Loss of appetite

9

Macrominerals

Mg availability affected by?

 Low content in feed

 Lower availability in fresh feed to conserved feeds

 High K

 High rumen ammonia

 Genetics

10

Macrominerals

Feed sources of Mg?

 Legumes

 Wheat bran

 Mg blocks

 Oral doses & MgCl2 in drinking water

11

Macrominerals

What is P needed for?

Bone development

• Nucleic acids, phospholipids, phosphoproteins

• Energy metabolism (ATP)

• Buffers

12

Macrominerals

Sources of P?

Milk

 Cereal grains

 Hay & straw low

13

Macrominerals

Signs of P deficiency?

Bone disorders like low Ca

 Lameness

 Low fertility

 Poor growth

14

Trace minerals

List the trace minerals

Cu

• I

• Se

• Fe

• Zn

• Co

15

Worst issue relating to trace minerals?

toxic accumulation

16

Trace minerals

Roles of Cu (copper)?

What are the copper antagonsist?

Many roles

 Enzymes

 Blood formation

 Etc.

• Absorption low in ruminants, reasonable in horses

• Antagonists  Mo  S  Fe  Zn

17

Trace Minerals

Cu deficiency disorders?

Anaemia

 Bone disorders

 Cardiovascular disorders

 Depigmentations

 Infertility

 Growth retardation

18

Trace Minerals

What is I (iodine) needed for?

Thyroid hormones

• Metabolism

• Foetal development

• Immune system

• Digestion

• Muscle function

• Require ~0.5ppm in feed

• Required daily to avoid goitre

• Goitrogenic plants increase deficiency

• Easily treated

19

TRace minerals

What is selenium needed for?

Protects body tissue from oxidation

• Helps prevent oxidative degeneration of fats

• Converts T4 to active T3 (thyroid hormones)

• Maintains immune function

• Absorption variable but low in ruminants

20

TRace minerals

signs of selenium deficiency?

 Ill thrift

 Low lamb survival and weights

 Low wool production

 White muscle disease

 High embryo mortality

 Retained placenta

 Reduced semen viability

 Reduced immune response

 Yellow fat disease

21

How does Vitamin E assist Selenium?

Prevents PUFA peroxidation

 Enhances immune system

 Helps Se stay in active form

 Prevents Se loss

22

TRace minerals

sources of selenium?

Most forages adequate unless in Se deficient soils

23

trace minerals

Treatment of Se deficiency?

Se injections & drenches

 Se lick blocks

 Se bullets

24

Vitamins

list the fat soluble vitamins

A D E K

25

Vitamins

List the water soluble vitamins

B complexes 

C

26

How are vitamins destroyed>?

By oxidation

27

What is Vit A needed for?

What is it created from?

None in plants

 Created from B-carotene (part of photosynthesis)

 Vision

28

Sources of vitamin a?

Green forage & yellow grain high

 Cereal grain low

 B-carotene causes yellowing of fat & distinct taste

 Excess toxic

29

What is vit D needed for?

Who is at risk of deficiency?

 Used with Ca for calcium homeostasis

 UV light & dried forage

 Deficient in indoor housed animals

30

What is Vit K needed for?

Signs of deficiency?

Sources?

 Required for blood clotting

 Poorly stored

 Deficiency can lead to haemorrhaging

 Sources  Microbes  Green leafy forage

31

What is Vit E needed for?

Sources?

Stored in liver

 An antioxidant for fat metabolism

 Immune function

 Wound repair

 High doses toxic (accumulate in fat)

 Sources  Wheat germ  Oil seeds & by-products

32

What are Vit B complexes needed for?

 Many different roles

 Not stored in large amounts

 Produced by microbes

 Aid in carbohydrate metabolism

33

Signs of Vit B deficiency?

Inappetite

 Anorexia

 Muscle weakness

 Poor growth

 Dermatitis

34

Sources of Vit B?

Green leaf, cereal grain & yeast

 Microbial synthesis

35

What is Vit C needed for?

Deficiency causes.... what disease?

Antioxidant

 Electron transport

 Collagen & noradrenalin synthesis

• Synthesise in liver from glucose

• Deficiency - Scurvy

36

Draw the energy partitioning flow chart

37

What is heat increment?

Food ingested produces heat

• The increase in heat produced as a result of the energy in the feed is the heat increment

38

What causes heat increment?

Eating

 Microbial metabolism (7 to 8% of ME intake)

 Nutrient metabolism

 Facilitated transport across luminal wall

39

ME Utilisation

what happens in -ve energy retention?

Animal loses body reserves

40

ME Utilisation

what occurs when energy retention is zero>?

 ME intake sufficient to meet maintenance

 No change in animal and no production

41

ME Utilisation

what occurs with +ve energy retention?

ME intake meeting maintenance and production

42

ME Utilisation

What is a k value?

Efficiency of animal to utilise its energy reserves to perform desired function

43

ME Utilisation

Efficiency for maintenance usually around...?

0.7 (70%)

44

ME Utilisation

Efficiency for growth in ruminants usually about...?

0.5 to 0.6

45

Metabolism

Where is protein stored?

– stored in large quantities (muscle) and used as a vital energy source when needed

46

Metabolism

What type of energy store is fat?

– large energy store that can be mobilised when needed

47

Metabolism

how is energy stored?

needed in a hurry so stored as carbs (glycogen)

48

Metabolism

Name the two energy molecules

 Adenosine triphosphate (ATP)

 Creatine phosphate (phosphocreatine)

49

Fates of glucose

List the 4 different fates of glucose

1. Aerobic metabolism

2. Anaerobic metabolism (fast-twitch muscle energy)

3. Glycogen synthesis

4. Fat synthesis 

50

Fates of glucose

what happens to glucose in aerobic metabolism?

Aerobic metabolism (normal metabolism – slow-twitch)  Oxygen available

 Glycolysis

 Conversion of pyruvate to Acetyl Co-A  Enter TCA cycle

 38 ATP produced 

51

Fates of glucose

What happens to glucose in anaerobic metabolism?

2. Anaerobic metabolism (fast-twitch muscle energy)

 Oxygen limited

 Conversion of pyruvate to Lactic acid

 2 ATP produced

 Lactic acid returns to liver to be converted into pyruvate 

52

Fates of glucose

what happens to glucose during glycogen synthesis?

3. Glycogen synthesis

 Short-term energy store

 Excess glucose stored in the muscle for use later

 Glucose homeostasis 

53

Fates of glucose

what happens to glucose during fat synthesis?

4. Fat synthesis

 Long-term energy store

 Excess glucose stored as fat (triglycerides)

 Through the Pentose Phosphate pathway

54

Lipid metabolism

list the 3 diff. fates of FA?

Partial breakdown (Catabolism)

Complete breakdown (Catabolism)

Storage as fat (Anabolism)

 • Lipid metabolism much more efficient that protein metabolism

55

Lipid metablism

describe partial breakdown of lipids

Partial breakdown (Catabolism)

 Converted to NEFAs – transported to liver

 Some used for glucose synthesis

 Balance converted back to fat

 High plasma concentration of FFA toxic - Ketosis 

56

Lipid metabolism

describe complete breakdown of lipids

 Complete breakdown (Catabolism)

 Converted to Acetyl Co A

 Enter TCA cycle to produce energy metabolism

57

Lipid metabolism

describe storage of lipids as fats

3. Storage as fat (Anabolism)

 Combined with a glycerol backbone to be stored as triglycerides

 

58

Protein metabolism

3 fates of protein?

1. Synthesise new proteins

2. Deamination and further metabolism to provide energy

 Amino group removed to form keto acid  Keto acid converted to glucose

 Process is very inefficient

3. Excretion

59

What is unqiue about ruminants in relation to glucose metabolism?

• Very little absorption of glucose from the rumen

• All glucose for ruminants originates from gluconeogenesis

 Propionate (VFA) transported to liver

 Converted into succinate (TCA cycle)

 Can be converted back to glucose via gluconeogenesis

• Fatty acids synthesised from acetate and butyrate  B-hydroxybutyrate

• Milk fat synthesised from acetate and ketone bodies

 Not glucose

60

What % of body weight if VFI?

What is VFI controlled by?

Intake usually ~ 2 to 3% of bodyweight

• Controlled by CNS & short and long term regulatory mechanisms

61

Describe regulation of VFI and factors affecting VFI

• Short term regulation

 Hunger v satiety

 Glucose & insulin levels in plasma

 Cholecystokinin released when digestive products reach duodenum

 Enlargement of stomach

• Long term regulation

 Adipose tissue (leptin)

• Other factors  Palatability  Physiology  Nutrient deficiencies  Choice feeding (nutritional wisdom)  Neophobia

62

List the constraints to ruminant VFI

1. Capacity to use energy

2. Feed physical properties

3. Environmental factors

4. Behavioural 

63

Describe the capacity to use energy as a constraint on ruminant VFI?

1. Capacity to use energy

 Energy demand

 Physiological state

 Parturition & lactation

 Number of offspring

 Genetics 

64

Describe feed physical properties as a constraint to ruminant VFI

 2. Feed physical properties

 Rumen constraints  Less than 8% of fibre in the rumen is digested each hour

 Intake negatively related to rumen digesta retention rate

 Large particle size increases retention rate

 More chewing and rumination required

 Higher digestibility means lower retention time = higher VFI

 Fibrous v WSC

 Nutrient deficiency in the rumen

 Low N & S = low microbial efficiency  Mineral deficiencies can reduce VFI

 DM% of feed

 Palatability 

65

Describe environmental factors as a constraint to ruminant VFI

3. Environmental factors

• Temperature

 Cold increases VFI to increase metabolic heat production

 Heat decreases VFI to reduce metabolic heat production

 Thermal neutral zone

 Photoperiod – Daylength

 Distance to water

 Chose between eating and walking to get a drink

66

Describe behaviour as a constraint to ruminant VFI

4. Behavioural

 Neophobia

 Fear of anything new

 Feed aversion

 Bad experience

67

Energy Systems

To formulate a diet the most important thing we need to know is?

Why is this?

  • energy content in feed and energy requirement of animal
  • Animal usual show a continuous response to increase in energy
  • First maintenance then production

68

Energy Systems

Describe Australian Standing Committee on Agriculture (SCA) energy system

 

  •  Based on British system
  •  Includes modifications for grazing (MEGraze) and temperature (Ecold)
  •  Includes efficiency for wool growth (kwool)
  •  10% of ME for production added to maintenance

69

Energy Systems

Energy requirements are maintenance plus...?

(possible production outcomes)

  • Growth
  •  Lactation
  •  Pregnancy
  •  Work
  •  Pelage growth

70

Energy Systems

What is basal/fasting metabolism?

is the energy expended (heat) for a fasting animal with no activity

71

Energy Systems

What is metabolic weight?

How do we determine it?

is the relationship between fasting metabolism and body weight

= weight to the power of 0.75

72

Energy Systems

Energy requirements are effected by?

  • Age (for growth and maintenance)
    - young animals lay down more muscle than fat 
    - less energy/kg liveweight gain
    - Older animal have greater energy storage / kg BW (FAT!!!)
  • Environment
  • Production state (eg lactation)

73

Protein Systems

Not all faecal protein dietary in origin.

What are other sources?

 

  •  saliva N
  •  bile N
  •  gastric secretion N
  •  pancreatic secretion N
  •  sloughed gut mucous membrane cells
  •  bacterial N

74

Protein Systems

Which diets have a high biological value?

diets w/ a high variety of amino acids

75

Protein Systems

Lack of agreement between in vitro and in vivo analysis of protein quality due to?

  • Small changes in 1 or more AA concentrations alter requirements for other AA
  •  Antagonism between AA
  •  Presence of anti-nutritive factors which lower absorption or utilisation of AA
  •  Animals respond better if N supplied as both essential & non-essential AA combined

76

Protein Systems

Protein quality for horses?

  • Dietary CP commonly used but inappropriate
  • Horse mostly digest protein in SI
  • MCP produced in large intestine not absorbed = excreted 
  • A better method of calculation is the available protein
    -  CP less NPN (as protein) - Acid Detergent Insoluble N (as protein)
    -  ADIN = bound protein unavailable for digestion & absoption

77

Protein Systems

How is most protein provided to ruminants?

Microbes!!!!

78

Protein Systems

 To formulate a diet for ruminants, need to know...?

  • Protein degradability
  •  MCP yield
  •  Digestion in SI of protein
  •  Efficiency of absorbed AA

79

Protein Systems

In ruminants, what effects protein degradability?

• Digesta rate of passage affects degradability

 Smaller particles travel faster than larger ones

 Flow rate increases when  Pregnant  Lactation increases

 VFI reduces

 Temperature

80

Protein Systems

Ruminant microbial yield affected by?
 

  • Level of fibre
  •  Rumen pH
  •  N availability

81

Protein Systems

Ruminants need sufficient ME for microbial synthesis, otherwise ..... results?

 Insufficient ME results in AA degraded to ammonia and lost as urine

82

Protein Systems

How much MCP leaves rumen and how much of that is digested?

What is the digestibility of UDP?

  • About 80% of MCP leaves rumen
    - and about 70% is digested
  • Undegraded protein (UDP; by-pass protein) digestibility varies but ~70%

83

Protein Systems

Look at lecture 27 Prac Beef Feedlot Nutrition (if you have time)

:)

84

Dairy Cow Feeding Example

Housed 5 yr old 600kg cow producing 30kg milk/d (36g/kg butter fat) not pregnant and offered a diet of 11MJ/kg DM (M/D)

-determine energy requirements

  • Need to consider:
  • Km
  • KL
  • EVL
  • ME(MEP in this case)
  • MEm
  • Total Requirement
  • DMI

85

Dairy Cow Feeding Example

600kg cow, 30L milk/day (32g/L protein) eating 21kg (231 MJ ME)

-Determine protein requirement

  • Consider:
  • Net protein
    -endogenous protein losses (EPL)
    -EUP
    -EFP
    -Dermal
    -Milk
  • Metabolisable protein requirement
  • RDP
  • Metabolisable MCP supplied
  • Metabolisable UDP requirement
  • Dietary UDP
  • CP
  • CP in diet