FSE Revision Flashcards
Macrominerals
List the macrominerals
- Ca
- P
- K
- Na
- Mg
- Cl
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
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
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
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
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)
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
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
Macrominerals
Mg availability affected by?
Low content in feed
Lower availability in fresh feed to conserved feeds
High K
High rumen ammonia
Genetics
Macrominerals
Feed sources of Mg?
Legumes
Wheat bran
Mg blocks
Oral doses & MgCl2 in drinking water
Macrominerals
What is P needed for?
Bone development
- Nucleic acids, phospholipids, phosphoproteins
- Energy metabolism (ATP)
- Buffers
Macrominerals
Sources of P?
Milk
Cereal grains
Hay & straw low
Macrominerals
Signs of P deficiency?
Bone disorders like low Ca
Lameness
Low fertility
Poor growth
Trace minerals
List the trace minerals
Cu
- I
- Se
- Fe
- Zn
- Co
Worst issue relating to trace minerals?
toxic accumulation
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
Trace Minerals
Cu deficiency disorders?
Anaemia
Bone disorders
Cardiovascular disorders
Depigmentations
Infertility
Growth retardation
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
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
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
How does Vitamin E assist Selenium?
Prevents PUFA peroxidation
Enhances immune system
Helps Se stay in active form
Prevents Se loss
TRace minerals
sources of selenium?
Most forages adequate unless in Se deficient soils
trace minerals
Treatment of Se deficiency?
Se injections & drenches
Se lick blocks
Se bullets
Vitamins
list the fat soluble vitamins
A D E K
Vitamins
List the water soluble vitamins
B complexes
C
How are vitamins destroyed>?
By oxidation
What is Vit A needed for?
What is it created from?
None in plants
Created from B-carotene (part of photosynthesis)
Vision
Sources of vitamin a?
Green forage & yellow grain high
Cereal grain low
B-carotene causes yellowing of fat & distinct taste
Excess toxic
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
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
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
What are Vit B complexes needed for?
Many different roles
Not stored in large amounts
Produced by microbes
Aid in carbohydrate metabolism
Signs of Vit B deficiency?
Inappetite
Anorexia
Muscle weakness
Poor growth
Dermatitis
Sources of Vit B?
Green leaf, cereal grain & yeast
Microbial synthesis
What is Vit C needed for?
Deficiency causes…. what disease?
Antioxidant
Electron transport
Collagen & noradrenalin synthesis
- Synthesise in liver from glucose
- Deficiency - Scurvy
Draw the energy partitioning flow chart
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
What causes heat increment?
Eating
Microbial metabolism (7 to 8% of ME intake)
Nutrient metabolism
Facilitated transport across luminal wall
ME Utilisation
what happens in -ve energy retention?
Animal loses body reserves
ME Utilisation
what occurs when energy retention is zero>?
ME intake sufficient to meet maintenance
No change in animal and no production
ME Utilisation
what occurs with +ve energy retention?
ME intake meeting maintenance and production
ME Utilisation
What is a k value?
Efficiency of animal to utilise its energy reserves to perform desired function
ME Utilisation
Efficiency for maintenance usually around…?
0.7 (70%)
ME Utilisation
Efficiency for growth in ruminants usually about…?
0.5 to 0.6
Metabolism
Where is protein stored?
– stored in large quantities (muscle) and used as a vital energy source when needed
Metabolism
What type of energy store is fat?
– large energy store that can be mobilised when needed
Metabolism
how is energy stored?
needed in a hurry so stored as carbs (glycogen)
Metabolism
Name the two energy molecules
Adenosine triphosphate (ATP)
Creatine phosphate (phosphocreatine)
Fates of glucose
List the 4 different fates of glucose
- Aerobic metabolism
- Anaerobic metabolism (fast-twitch muscle energy)
- Glycogen synthesis
- Fat synthesis
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
Fates of glucose
What happens to glucose in anaerobic metabolism?
- 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
Fates of glucose
what happens to glucose during glycogen synthesis?
- Glycogen synthesis
Short-term energy store
Excess glucose stored in the muscle for use later
Glucose homeostasis
Fates of glucose
what happens to glucose during fat synthesis?
- Fat synthesis
Long-term energy store
Excess glucose stored as fat (triglycerides)
Through the Pentose Phosphate pathway
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
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
Lipid metabolism
describe complete breakdown of lipids
Complete breakdown (Catabolism)
Converted to Acetyl Co A
Enter TCA cycle to produce energy metabolism
Lipid metabolism
describe storage of lipids as fats
- Storage as fat (Anabolism)
Combined with a glycerol backbone to be stored as triglycerides
Protein metabolism
3 fates of protein?
- Synthesise new proteins
- Deamination and further metabolism to provide energy
Amino group removed to form keto acid Keto acid converted to glucose
Process is very inefficient
- Excretion
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
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
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
List the constraints to ruminant VFI
- Capacity to use energy
- Feed physical properties
- Environmental factors
- Behavioural
Describe the capacity to use energy as a constraint on ruminant VFI?
- Capacity to use energy
Energy demand
Physiological state
Parturition & lactation
Number of offspring
Genetics
Describe feed physical properties as a constraint to ruminant VFI
- 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
Describe environmental factors as a constraint to ruminant VFI
- 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
Describe behaviour as a constraint to ruminant VFI
- Behavioural
Neophobia
Fear of anything new
Feed aversion
Bad experience
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
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
Energy Systems
Energy requirements are maintenance plus…?
(possible production outcomes)
- Growth
- Lactation
- Pregnancy
- Work
- Pelage growth
Energy Systems
What is basal/fasting metabolism?
is the energy expended (heat) for a fasting animal with no activity
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
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)
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
Protein Systems
Which diets have a high biological value?
diets w/ a high variety of amino acids
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
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
Protein Systems
How is most protein provided to ruminants?
Microbes!!!!
Protein Systems
To formulate a diet for ruminants, need to know…?
- Protein degradability
- MCP yield
- Digestion in SI of protein
- Efficiency of absorbed AA
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
Protein Systems
Ruminant microbial yield affected by?
- Level of fibre
- Rumen pH
- N availability
Protein Systems
Ruminants need sufficient ME for microbial synthesis, otherwise ….. results?
Insufficient ME results in AA degraded to ammonia and lost as urine
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%
Protein Systems
Look at lecture 27 Prac Beef Feedlot Nutrition (if you have time)
:)
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
- MEL (MEP in this case)
- MEm
- Total Requirement
- DMI
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
