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summary principles of animal nutrition
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Leerstof Principles of Animal NutritionHoorcollege 1 05-01-15
Animal feed additives are for example vitamins.
A compound feed = concentrate (more ingredients) = pellets.
Ingredient = feedstuff
Nutrition value: evaluation systems (= set of equations)
Nutrition requirements: close-respons. Factorial
Defenition animal nutrition: to match the requirements for certain nutrients of an animal at any
moment during its life cycle with the value of those nutrients on a diet.
Hoorcollege 2 06-01-15
If you’re feeding chickens food with big and small particles, they’ll only pick the larger particles it
selects certain nutrients (but not per se better nutrients). So the industry feeds with coarse pellets.
Disadvantage: these are dissolved in the crop (first stomach)
feed Growth/production
All the birds in 1 floor pen together are 1 measure unit. From these birds you measure the feed
intake and growth (for the whole group), not just 1 individual.
Feed Conversion Ratio (FCR): kg feed
kg growth/milk/eggs
Lower doesn’t mean better something can be wrong with the animal. Health is also important.
< 1950: mixed farming animals are ‘waste converters’.
Waste converters eat the waste of the crops on farms. Mostly when there is ‘mixed farming’.
Between 1950 and 1990: efficient feed conversion selection on FCR
From early ’90 and onwards: functional feed insoluble fibres; diurnal feeding; the society
emphasizes animal welfare and the environment.
Criteria for Animal Feed:
Safe! (for animal and the end product of the consumer)
Matches the physiological requirements
Cheap to buy
Environment friendly (manure, process of production)
Appearance: colour, smell, taste, texture (pets)
what the industry feeds. More than the animal needs. This
is a compensation for minor values in the nutrients,
infection pressure, hygienic circumstances and different
diets.
FCR is driving how environment friendly pet food is.
Value of feedstuffs:
energy value
protein value
physical (feed form) value
,Composing a complete diet
Combining feedstuffs in one diet based on:
palatability (taste)
feeding value of feedstuffs
‘optimal’ nutrient contents
Optimizing value for money: least-cost formulation
software
E lower is like building a house: you have the building
blocks (protein) to build, but without the cemetery
(energy), you can’t do anything.
Animal
feed Growth/production
(nutrients) (‘product’)
It is a two steps process: digestion and absorption
Utilization
Feed for maintenance = ‘fixed’ quantity, Energy
Feed for production = variable, pretein/amino acids
Digestion: breaking down nutrients into smaller particles so the gut wall can absorb it.
Absorption: passing through the gut wall
Utilization: using a ‘building block’ in your body
These three are different things!
A high digestability doesn’t mean that everything is used 45 – 60% is utilised. Everything else will
be excreted. A high Nnon utilised means a high FCR. To increase Nutilize you can:
Feed the amount of feed at the moment that you are sure that the animal metabolically
needs it the most.
Make the food balance look like the balance of the body growth/milk production
matching the amino acid profile of the diet, with the amino acid profile of the animal itself.
Pool
Input Output
“push” “Pull”
Push: there’s an input of nutrients and we just see what the respons is. Used now.
Pull: we feed what the animal needs. Used earlier.
Hoorcollege 3 07-01-2015
Composition of feed
Water Dry Matter
Ash (inorganic) Organic Matter
- Soluble - Protein
- HCl insoluble Ash - Fat
- Carbohydrates
- Rest
, The composition of dry matter determines the nutritional value of the feed. The nutritional value of
proteins depends on its amino acid composition. Nutrition value of carbohydrate fraction depends on
the ratio between structural (i.e. fibre) and non-structural carbohydrates (i.e. sugars and starch).
Normally 10% of the feed is water, but animals don’t use the feed for their water consumption.
CP = crude protein
Lucerne contains a lot of fibres, so we don’t
feed all animals with it, only the ruminants
who can digest it.
The composition of diet can be known by:
1. Calculation for table value for the
individual feed ingredients.
easy and cheap but less accurate.
2. Conducting analyses in the diet:
Expensive but more accurate.
Analyses are conducted to get more accurate information about the chemical composition of the
feed. There are two main reasons for this:
Table values are always an average for a specific feed ingredient.
Composition of a diet depends also on the accuracy of mixing of the different ingredients.
Proximate or Weender analyses: compromises between costs and accurate information. Set of
analytical methods to get a good picture of the nutritional composition of the feed by using simple
procedures and equipment. This is simple, cheap and standardised. You divide the composition of
the feed in a group of nutrients and then use common properties of these nutrients for their total
determination. The analytical procedures are described in national and international guidelines. This
is to compare results found by different laboratories and the models to predict animal production are
based on correlations found between feed composition and animal performance. For example:
Water: drying sample at 103 oC (used boiling point)
Ash: removing organic matter by burning at 550 oC
Proteins: contain –NH2 group: Kjeldahl method
Fat: not soluble in water: extraction with non-polar solvent.
Carbohydrates are a heterogeneous group. They can be divided into:
Crude fibre: organic fraction which is not soluble in acid and alkaline solution.
N-free extractives: calculated value. Contains (most important) starch and sugars (non-
structural carbohydrates) and a residue fraction.
Alternative analytical methods are needed for determination of specific chemical compound such as
a specific mineral or amino acid. They require sample preparation and use of sophisticated
equipment and analytical skill: much more expensive.
NIR: Near infrared spectroscopy: Used as alternative for the Weender analysis. The prinicples are
absorption of solid sample within NIR spectrum and a correlation between amount of a nutrient and
absorption at specific wavelength. More absorption will take place if there are more nutrients in it.
Advantages are that all analyses are in one run, there is no sample preparation and it is cheap.
Disadvantages: correlation varies between different feeds and the results are not accepted for
scientific work.
! important ! There is a difference between amount and content.
Amount: is a volumetric content (hoeveelheid)
Content: how much is in there compared to the total (gehalte)
Formula for calculation Nutrient content based on dry matter:
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