ration formulation

Question 1

manual ration formulation

Answer 1

• need animal’s requirements
• need feedstuffs used & their compositions
• need mathematical way to combine feedstuffs to satisfy requirements
• balanced diet doesn’t necessarily have every nutrient in exactly the correct amount → has nutrient needs met w/out any of the nutrients in excess so much that it’s harmful
• ration based on percentage of diet (works well w/ chx & poultry)
  
  • works well when you don’t need to worry about how much an animal will consume → let animal eat all they can (free access)
• ration based on per head per day more useful for ruminants & horses

Question 2

balancing on a % ration basis

Answer 2

• can be done on as-fed OR DM basis (convert PRN at the end)
  - e.g. pigs & swine have high DM so can do as-fed & convert at end
  - high-moisture feeds should convert DM first
• all feedstuffs must add up to 100 (100kg or 100 lbs or 100%)
• leave a certain amount of slack space for adding vit/min, abx (3%)
• can have “fixed” ingredients but must specify the amount

Question 3

considerations for ruminant rations

Answer 3

• balancing ration on a ‘quantity per animal per day’ basis is more useful for ruminants & horses
• balance on a DM basis & convert to as-fed at the end
• focus on energy requirements first or animal can gain/lose weight but need to balance for CP as well
• must consider the amount that an animal can eat (e.g. % of BW) → nutrients must fit w/in that amount
  
  • poor quality forage (mature - has ↑ CWF/NDF) can limit the amount the animal is able to consume
• ↑ NDF ↓ intake (inverse relationship)
  
  • animal can consume 2.5-3% BW of high forage quality (<50% NDF)
  • animal can consume 2% BW medium forage quality (50-60% NDF)
  • animal can consume 1-1.5% BW of low forage quality (>60% NDF)

Question 4

what percentage of BW can an animal consume of poor quality forage (>60% NDF)?

Answer 4

1-1.5%

Question 5

what percentage of BW can an animal consume of medium quality forage (50-60% NDF)?

Answer 5

2%

Question 6

what percentage of BW can an animal consume of high quality forage (<50% NDF)?

Answer 6

2.5-3%

Question 7

limitations of algebraic solutions in ration formulation

Answer 7

1. can only work with 2 feedstuffs/mixes at a time
2. can only balance 1 nutrient at a time
3. no flexibility on target value (set)
4. cannot set a minimum or maximum value
5. no ability to optimize cost ➔ stuck w/ the cost of those 2 ingredients

Question 8

advantages of ration formulation programs/software

Answer 8

able to deal simultaneously with:

1. multiple nutrients
2. numerous feedstuffs
3. ranges (minimum & maximum)
4. least cost ration formulation

Question 9

requirements for ration formulation programs/software

Answer 9

1. know composition & prices of feedstuffs
2. good selection of feeds & ingredients
3. knowlege to evaluate the final ration: practicality, palatability, toxicity