ANSC 4280 Poultry Nutrition Exam Questions with Complete Solutions Benefits of Grinding (particle size reduction) - Correct Answer - Improve nutrient digestibility
- Improve feed mixing
- Improve pellet quality
- Increase in dust pollution and moisture losses
- Cause flowability problems during feed manufacturing
- For broilers; increased GI passage rate, poor gut health and low nutrient digestibility
- not yet widely used
- Pellet quality (finer is better)
- Mixed feed is ground after mixing through hammer mill
- Feed is mixed by controlling flow rates through each of the 5 compartments
Shortfalls of Grinding (particle size reduction) - Correct Answer - Excessive grinding is expensive
Hammer Mill - Correct Answer - By far most common; feed is struck by a hammer and shattered until it passes through a screen) Roller Mill - Correct Answer - rushing, cutting and shearing of feed as it is pulled between rollers
smaller throughput but more energy efficient -Better uniformity (vs hammer mill) -Physical characteristics of fibre are better maintained (stimulate gut function and health) How to determine optimum particle size - Correct Answer - Effects on nutrient utilization (finer is better) -Cost of grinding (finer is more expensive) -Feed dust and bridging of feed (Worse when finer)
Volumetric mills - Correct Answer - Used for small and medium operations, blending premix, corn and soybean meal
Heat processing - Correct Answer - Physical process (uses heat and friction) 1 / 2
- Mixes meal with steam and push it through die
- Disrupts cell structure
- Reduces feed wastage (reduce selection)
- Prevents separation of feed
- Improves flow of feed
- Improves feed hygiene (kill pathogens)
- Allows more effective use of some co- products
- Feed material is plasticized in a tube by a combination of moisture, heat and mechanical shear.
- Elevated product temperature and pressure within the tube, gelatinization of starch, denaturation
- Low dust
- Better sterilization of feed
- Improved pellet quality
- Protein degradation
- / 2
-'cooks' (gelatinizes) the starch and other nutrients
-Destroys moulds/bacteria (not mycotoxins) Post -pelleting :Crumbles - Correct Answer - A crumbler is a roller mill with rolls specially designed for breaking up pellets into smaller particles Benefits of pelleting - Correct Answer - Improves nutrient digestibility (thermal modification of starch and protein)
Allows a finer grind of feed
Extrusion/ Expansion - Correct Answer - Combination of heat from injected steam and friction by pushing through a die; high temperature and pressure
of proteins (ANF), stretching or restructuring of tactile components and the exothermic expansion of the extruded material within seconds.Pelleting vs Extrusion (advantages) - Correct Answer - Extrusion has higher temperature and can handle more fat -Extrusion has increased gelatinization of starch
Pelleting vs Extrusion (disadvantages) - Correct Answer - High energy consumption