Term
| What are the proximate nutrient groups? |
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Definition
Dry matter (or total moisture)
Gross energy
Crude Protein
Ether Extract
Crude Fiber
Nitrogen free extract
Ash
Vitamins |
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Term
| Give some examples of things included in the nitrogen free extract component of proximate nutrient analysis |
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Definition
Starches
Sugars
Soluble fibres |
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Term
| What are the classifications of feed ingredients? |
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Definition
Energy feeds (starches & sugars)
Protein feeds
High fiber feeds / roughages
Macro-mineral supplements
Fat or oil supplements |
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Term
| Give an example of energy feeds |
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Definition
cereal grains
legume seeds of peas, filed beans |
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Term
| What is the purpose of adding fat/oil supplements to the diet |
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Definition
Increase energy density of the feed
Improve palatability
Reduce dustiness |
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Term
| How do you calculate dry matter in feed? |
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Definition
Total weight % - total moisture %
(sample weight after drying) / (sample weight before drying) X 100 |
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Term
| What are the two types of water found in feeds? |
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Definition
Free water - in the feed matrix, not bound through hydrogen bonding
Bound water - water which exists in feeds via hydrogen bonding |
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Term
| Why do protein and carbohydrates attract more bound water? |
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Definition
| They contain more polar molecules |
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Term
| How would you go about measuring dry matter in samples |
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Definition
1. Weight out 1-2g samples of feeds
2. Place samples in oven at 135 degrees overnight
3. Transfer sample to a dessicator with drying agents to remove moisture in air
4. Allow samples to cool
5. Weigh residues |
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Term
| What are some mistakes commonly made in measuring DM? |
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Definition
-oven set at too low a temperature
-samples not left to dry long enough
-moisture in headspace of dessicator
-leaking of air into dessicator
-weighing back process takes too long
Moisture in the air will bind to the matrix of the feed sample quickly! |
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Term
| How would you go about measuring free water in samples |
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Definition
1. Weight out 1-2g samples in crucibles
2. Place samples in oven at 65C or freeze drier for 4-5 days
3. Remove samples and leave in container overnight to restore equilibrium of air moisture
4. Weigh back residual feed weight
5. Calculate free water loss |
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Term
| What are some methods of making 'air dry' feeds? |
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Definition
Good farming practices. Allow hay to dry before baling, proper harvesting for cereal grains/oil seeds
Industrial scale electronic hydration processing (expensive!) |
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Term
| What causes mycotoxins to form in feeds? |
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Definition
| free water allows fungus/mould to develop! |
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Term
| What are feeds on an air-dry basis? |
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Definition
-contain no free water, but are well saturated with air moisture which is bound via hydrogen bonds
e.g. dry hay, well processed dry feeds, DDGS, casein powder |
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Term
| What are feeds on a dry matter basis? |
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Definition
| Contain no free or bound water |
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