Nutrients of practical value Flashcards
Is sampling an important variable in feed analysis
Yes
Most common methodology to assess feed nutrients
Proximate analysis (wet lab analysis)
Proximate analysis is an estimation of
Feed components, not necessarily nutrients
Feed is made up of _________ & ____________ (1st division)
Moisture & Dry Matter
Dry matter is made up of ________ & _________
Inorganic material & organic material
Feed inorganic material
Called Ash, made up of minerals
Organic material of feed is made up of ___________& __________
Protein & non-nitrogenous residue
Protein is also called
Crude protein (CP)
Non-nitrogenous residue is made up of _______ & __________
Ether Extract & Carbohydrates
Ether extract is
Fat
Carbohydrates of feed are made up of _____ & ______
Nitrogen Free Extract & Crude Fiber
Crude Fiber is made up of ______ & _______
Neutral Detergent Fibre (NDF) & Acid Detergent Fibre (ADF)
What is Nitrogen-Free Extract
Soluble carbohydrates (like starch, etc)
All components of proximate analysis are determined analytically except
NFE, which is determined mathematically
How to determine DM of a feed
Moisture content = loss in weight that results from drying a known weight of feed (wet weight) from an amount of time at 55 or 105 °C , then measuring the weight after drying (dry weight)
Moisture content = dry weight / wet weight x 100%
- make sure u don’t include container weight in ur calculations
_________ is the most important part of a feed / ingredient as it contains all the nutrients
DM
Determining DM or moisture content in a feed is critical for
Formulating animal diets
Water dilutes _____ & ______ in feed
Energy & nutrients
Moisture content modifies
Feed intake and performance
Increased water in feed means
Increased weight which means increased transport costs
Procedure of water and DM determination for samples that contain large amounts of volatile substances (eg VFAs & essential oils)
Dry at low temperature (55 °C) or freeze dry
What has high VFA
Silage
On a DM basis, do nutrients increase or decrease
Increase, as water is no longer diluting them
Crude protein measures the amount of ________ in feed
Nitrogen
How to determine CP of a feed
Kjeldahl method or Dumas Technqiue
On average, protein in feed contains around _______% Nitrogen
16% N
100% (total protein) / 16% (Nitrogen) =
6.25 - a constant that is used for CP calculations
CP% =
Total NItrogen (Kjeldahl) x 6.25
Limitation of CP calculations
CP% includes true protein and non-protein nitrogen (free amino acids, amides, nitrates, nitrites, nucleic acids, UREA)
Urea = 46% N so CP would be 288% - however, it was my impression that we just don’t care? If someone got another impression pls let me know
EE made up of
Lipids, organic acids, alcohol, pigments, fat-soluble vitamins, and carotenoids but also plant waxes, essential oils, resins
How to find EE
Dried and ground feed sample continuous extraction (4h, 40-60°C) in a solvent (petroleum or diethyl-ether) & then you evaporate the solvent, and reside is EE
EE is often referred to as
Crude Fat
EE% =
EE residue weight / sample weight x 100%
More sensitive EE methodologies
Gas chromatography & HPLC
Crude Fibre - how to figure out the old fashioned way (sorry about this one it sucks)
Sample (A) of defatted EE residue is sequentially boiled in weak acid (H2SO4) and alkali (NaOH) solutions to stimulate digestion. Residue is washed (Hal & ether), filtered, dried and weighed (B).
B is burned in a furnace at 550°C and resulting ash weighed (C)
CF% = (B - C)/ A x 100%
Is finding CF tedious and not highly repeatable
Yes
What was the old CF system replaced with
The detergent Fiber system
How does the detergent Fiber system work
Digest feed with neutral detergent - breaks feed into cell contents and residue (hemicellulose, cellulose, & lignin) - NDF
Digest NDF with acid detergent - hemicellulose filtered out and left with cellulose & lignin - ADF
Digest ADF with 72% sulfuric acid - cellulose filtered out and lignin is left
High ADF means the diet is
Highly indigestible
What is Ash
Inorganic material in the feed (minerals)
Ash is determined by
Ignition of a known weight of feed at 550°C until all organic material has burned away (5-6 hours)
Dm - Ash =
Organic matter (OM)
Newer, more sensitive methodologies for Ash %
Spectroscopy - can give individual mineral components
Nitrogen Free extract
Elements without nitrogen and non extract either - everything left - supposedly represents more digestible CHO
How to calculate NFE
% NFE = 100 - (% EE + % CF + %CP + % Ash)
What is alternative feed analysis
Near infrared Sceptropscopy (NIRS) or Chromatograpy
What is NIRS
Near Infra-Red Spectroscopy which does rapid and non-destructive analysis of feeds and mixed diets
Detects reflection of near-IR light (absorption and reflection) of OH/CH/NH groups (proteins, lipids, fibre, moisture, minerals)
REVIEW DM to AS FED AND AS FED TO DM
Ok
REVIEW ASSIGNMENT FOR CALCULATION EXAMPLES!
YES
