Nutrition 1 - Week 8 Flashcards
(100 cards)
Give the formula to calculate Digestibility (%)
((intake-faecal)/total intake) x 100
If something was 100% digestible, what would this mean?
it would mean that everything that is consumed is utilised and therefore no faeces are produced
State 7 factors affecting Digestibility
food composition
ration composition
preparation
enzyme suplementation
individual variation
species variation
level of feeding
Digestibility: How does Food composition affect Digestibility? (3)
different nutrients have different digestibilities
some nutrients, such as glucose, are highly digestible
some nutrients, such as fibre, are less digestible
Digestibility: How does Ration Composition affect Digestibility?
- Give an example
the digestibility of some feedstuffs can be affected by other dietary components
high starch diets in ruminants decrease rumen PH and may inhibit microorganism fibre digestion
Digestibility: How does Preparation affect Digestibility?
- State 6 examples of different preparations
the preparation of the food can determine how accessible the nutrient is for digestion in the GI tract
rolling, crushing, grinding, alkali, heating, micronisation
Digestibility: How does Enzyme Supplementation affect digestibility?
- For which group of animals is this especially helpful for?
adding enzymes may increase digestibility
non ruminants
Digestibility: How does Individual variation affect Digestibility?
different individuals of the same species may find some feedstuffs more or less digestible than other individuals
Digestibility: How does Species Variation affect Digestibility? (3)
forages have higher digestibility for ruminants than non ruminants
sheep tend to digest grain better than cattle
cattle tend to digest low quality forage better than sheep
Digestibility: How does Level of Feeding affect Digestibility? Use the example of a large volume of food is ingested (4)
- Which type of component will level of feeding affect most severely? Give an example
a larger volume of food is ingested
which increases passage time
and decreases the time for digestive action of enzymes
so lowers the apparent digestibility
slowly digested components like fibre
Why does Grass digestibility decrease as grass grows longer?
- State specific nutrients affected and whether they increase or decrease (6)
because the stems and stalks are longer so the grass contains more structural carbohydrates with a lower digestibility and less storage carbohydrates with a higher digestibility
lignin content increases
cellulose content increases
hemicellulose content increases
sugar content increases
protein content decreases
lipid content decreases
Describe the structure of Lignin
- why is Lignin practically indigestible?
- What does it do to closely associated polysaccharides?
it is a complex cross linked alcohol polymer
because it has high resistance to chemical degradation
it reduces the digestibility of them
State the 3 ways of measuring amounts of different fibres in feedstuffs
natural detergent fibre
acid detergent fibre
modified acid detergent fibre
Fibre Measurement - How does NDF work?
- Which fibres does this method measure the amounts of? (3)
- What other fractions does this method measure from the forage? (4)
boil the feedstuff in sodium laurel sulphate and EDTA
lignin
cellulose
hemicellulose
sugars
lipids
soluble protein
starch
Fibre Measurement - How does ADF work?
- Which fibres does this method measure the amounts of? (2)
reflux the feedstuffs with sulphuric acid and cetyltrimethylammonium bromide
lignin
cellulose
Fibre Measurement - How does MADF work?
it is a modification of ADF with increased acid strength and increased boiling time
State 10 factors controlling food intake
physical
chemical
nervous/hormonal
physiological
palatability
deficiencies
illness
heat
obesity
availability
Food Intake: How do Physical factors affect food intake?
- Give an example of a physical factor affecting food intake
the size of the stomach, rumen or crop can limit the amount of food that can be consumed
the foetus in late pregnancy can restrict the stomach size, especially in sheep
Food Intake: How do Chemical Factors affect food intake? (2)
- Give an example of this in non-ruminants (2)
- Give an example of this in ruminants
different species have different chemicals which induce a feeling of satiation
this will reduce feed intake as the animal feels full and does not want to eat anymore
glucose
cholecystokinin
Why is it important to be able to predict/estimate food intake? (6)
diet formulation
feed availability
feed budgeting
reducing feed wastage
determining stocking densities
conservation management
State 3 different things you could use to predict food intake
animals weight
rules of thumb
nutrient requirement tables
Predicting food intake: How can we predict food intake based on the animals weight?
by using complex equations
Predicting food intake: How can we predict food intake based on rules of thumb? (in g of DM per kg /day) (7)
22 for beef cattle
28 for dairy cattle in early lactation
32 for dairy cattle in peak lactation
15 for dairy cows in dry period
1 for sheep and lambs
3 for sheep in late gestation
2kg dry matter per 100kg body weight for horses
Describe how feeding standards come up with nutrient requirement information
- Have there been many UK requirements?
- Give information surrounding the most recent UK nutrient requirement stands (2)
the findings are usually the output of a committee of experts
no
it was conducted in 2003 and was a nutrient requirement standard for pigs
published by BSAS