1. Handling Feeds (Processing, Mixing, Storage) 10-8-12

2. FEED PROCESSING
Feed cost is normally the single largest expense associated with any animal production operation
> 50%
Often up to 80%

3. Why Process Feeds? Alter physical form Alter particle size
Prevent spoilage
Isolate particular portion of plant
Improve palatability
Inactivate toxins or antinutritional factors
Ease of handling
Increase digestibility

4. How does processing increase digestibility?
Improve intake
How does this affect digestibility?
How does this affect nutrient uptake?
Increase surface area of particles
More surface area for chemical and enzymatic reactions
Alters molecular structure
Denaturing, cooking starch, etc…

5. How are feeds processed?

6. Grain Processing Cold or Hot Processing Dry or Wet Processing Cold Hot
Cracking, grinding, soaking, reconstitution, high moisture grain, acid preservation
Hot
Steam rolling or flaking, pelleting, extrusion, popping, micronizing, roasting
Dry or Wet Processing

7. Grinding/Cracking – Cold Processing
Various scales of grinding
Hammer mill or Roller Mill
Most common method
Inexpensive
Simple

8. Cracking & Grinding - Roller Mills
Act on grain by compressing it between two corrugated rolls that can be screwed together to produce smaller and smaller particles.
Figure 11.3 Top. One type of a roller mill used for processing grain. Right. The large corrugated rolls that physically crush the grain as shown. Courtesy of Automatic Equipment Mfg. Co. Pender, NB.

9. Roller Mills Products can range in size
cracked grain to a fine powder = corn, wheat, or milo
Flattened to powder = course grains (barley, oats)
The hulls won’t grind into powder well with roller mills
Roller mills produce a less dusty feed than a hammer mill.
If the grain is not ground too finely, the physical texture is very acceptable to most species.
Swine diets - very finely ground
Roller mills are not used with roughage.

10. Hammer Mills Process feed using rotating metal
bars (hammers) that blow the ground product through a metal screen.
Particle size is controlled by changing the screen size.
Figure 11.5 One example of a portable grinder (hammer mill) and mixer available for on-the-farm use. Courtesy of Richard Kellems.

11. Grinding - Summary
Grinding improves nutrient utilization by disrupting the outer protective coating and increasing the accessibility of the digestive secretion to the materials inside.
Coursely ground grains are preferred for ruminants
Not palatable when fine, or dusty
Fine ground common for poultry and swine
Grinding is comparable to other processing methods when intake of grain is low.

12. Soaking Grain – Cold/Hot Method
Grain soaked for 12 to 24 hours in water
Soaking, (may also be heat), softens the grain, which swells, making a palatable product that should be rolled before use in finishing rations.
Research does not show any marked improvement in feed efficiency as compared to other processing.
Space requirements, handling problems and potential souring discourage large-scale use.

13. Reconstitution – Cold Method
Reconstitution is somewhat similar to soaking.
Water is added to mature, dry grain to raise the moisture content to 25% to 30%.
Stored in an oxygen-limiting silo for 14 to 21 days.
Improved gain and feed conversion by beef cattle fed high-concentrate rations when whole grain used (milo and corn)
Does not work well if grain is ground prior to reconstitution. Milo should be rolled after.
Some fermentation takes place during holding.
Disadvantage is in regard to capacity and holding

14. High-Moisture Grain
High-moisture grain refers to grain harvested at a high moisture content ( 20 to 35%) & stored in a silo or under plastic to preserve the grain.
Can be further processed before or after ensiling.
May be useful when weather doesn’t allow for drying in the field
High-moisture grain produces good feedlot results, with feed conversion particularly improved over dry grain.
Disadvantages
mold if weather is not cold, mishandled, or improperly stored, not chemically treated.
Storage costs may be high.
More difficult to dispose of than dry grains

15. High-Moisture Grain – Acid Preservation
1 – 1.5% addition propionic acid, mixtures of acetic & propionic acid, or formic & propionic acid
Prevent mold and spoilage
Won’t affect animal performance if mixed correctly

16. Hot Processing Methods
Methods for heat processing include:
Common: Steam rolling and flaking; extruding, pelleting
Uncommon: Popping, micronizing, and roasting.
Some methods are time, equipment and cost prohibitive
Micronizing, popping, roasting

17. Popping, Micronizing, Roasting
Popped corn is produced by action of dry heat, causing a sudden expansion that ruptures the endosperm of the grain.
Increases gut and rumen starch utilization but results in a low-density feed.
Popped feed usually is rolled to reduce bulk.
Micronizing is essentially the same as popping, but heat is provided by infrared energy.

18. Steam Rolling – Hot Process
Steam rolling has been used since the 1940s, partly to kill weed seeds.
Steam passes up through a chamber that holds the grain above a roller mill.
Grains are subjected to 3- 5 minutes of steam BEFORE being rolled.
Does NOT modify the starch but it DOES soften the seed.
Less fines and larger flakes than dry/cold rolling – typically improve animal performance

19. Steam Flaking Grains Steam-flaking, used since the 1960s
Grains subjected to high-moisture steam for minutes.
Rolled
Feeding value can improve by 12% to 15%.
The thinner the grain is flaked, the lighter the bushel weight & faster the rate of in vitro starch digestion.

21. Steam Flaking
Steam flaking allows more efficient rupture of starch granules, for a more desirable physical texture in the finished product.
Starch becomes gelatinized – intermolecular bonds of starch break down (water causes swelling) which allows hydrogen binding sites to engage more water which dissolves the starch granules.
Corn, barley & sorghum usually give a good response in terms of increased gain & feed efficiency.

22. Extrusion
Extruded grains or other feeds are prepared by passing the feed through a machine with a spiral screw, forcing the feed through a tapered head.
Moisture is added
Heat is added
Pressure is added
Starch is gelatinized
Puffs and changes texture due to loss of heat and moisture at the end of the process
Dried but retains the porosity

23. HOT Pelleting
Pellets, available commercially for over 50 years, come in different diameters, lengths & hardness.
Figure 11.7 One type of pellet mill widely used for pelleting concentrates. A quick-change die is shown at the left. Roughages can be pelleted, but production is reduced & costs are appreciably higher.

24. Pelleting
Pelleting is accomplished by grinding feed and forcing it through a thick, spinning die by rollers.
Feedstuffs are usually steamed to some extent prior.
Typically not enough to gelatinize the starch.
Palatable
High percentages of poultry, horse & swine feeds are pelleted.
Not as palatable for ruminants on high – grain diets. Will see reduction in feed intake. Works well for forages.
Supplemental feeds such as protein concentrates are often pelleted, so that they can then be fed on the ground or in windy areas with much less loss.

25. Pelleting - Roughage Advantages
Pelleting roughages puts them in free flowing form
Must be ground prior to pelleting – expense
Reduce space requirement by as much as 75%
May increase intake of forages
Reduces dustiness
Increase efficiency for low-quality forages
Disadvantages
Cost of additional processing (more costly for roughage than for concentrate)
Reduces the roughage value of hay

26. Examples of diet effects on VFA production
Forage:Concentrate
VFA, Molar% 60:40 40:60 20:80
Acetate
Propionate
Butyrate
Methane, Mcal/d
Physical form of forage
Alfalfa hay
Grind
VFA, Molar% Long Coarse Fine Pelleted
Acetate
Propionate
Butyrate

27. Poultry - Pellets Typically fed crumbles rather than pellets
More water consumption on pellets (10 – 20%)
More cannibalism
Crumbles are rolled pellets
Item
Mash
Crumble
Re-ground Crumble
Corn soy diet
Avg. weight (g)
407
471
461
Feed/Gain
2.06
1.90
1.96

28. ROUGHAGE PROCESSING Pelleting
Pelleting usually gives greatest relative increase in performance for low-quality roughages.
Increased density, rapid passage through the GI tract, and reduced digestibility is normal.
Net nutrient uptake is increased because of the increased consumption.
Pelleted, high-quality roughages produce performance in young cattle or lambs almost comparable to that yielded by high-grain feeding.

29. ROUGHAGE PROCESSING Pelleting
In ruminants, less cellulose is digested, relatively less acetic acid is produced, and relatively more digestion takes place in the intestines.
Because pellets pass out of the rumen more rapidly.
Feeding finely ground, pelleted rations for long periods of time may be detrimental to the rumen.
Animals fed in this manner will develop hyperkeratosis of the rumen papillae, which reduces absorption and performance.

30. ROUGHAGE PROCESSING Baled Roughage
Baling is still one of the most common methods of handling roughage, particularly where it is apt to be sold or transported some distance.
Figure 11.9 Unloading large bales of hay.
Baling has a considerable advantage over loose hay stacked in the field, or in other, less-dense forms.
Large bales are becoming more common.

31. Baled Roughage
Although handled mechanically for the most part, it still requires more hand labor than many other feedstuffs.
Considerable waste may occur in feeding, depending on how it is fed, and level of feeding.
Heavily fed animals such as dairy cows may be quite selective, so that coarse stems will not be consumed.

32. ROUGHAGE PROCESSING Chopped and Ground Roughage
Chopping or grinding puts roughage in a physical form handled readily by mechanical equipment.
Also tends to provide a more uniform product and usually reduces feed refusal & waste.
Many feed trucks are now able to chop hay in the mixing chamber.
Additional expense is incurred by grinding, and loss of dust may be appreciable from grinding with a hammer mill.
To reduce dust loss, fat or molasses is sometimes sprayed on bales before they are ground.

33. Figure An example of a tub grinder, a type that is very useful for grinding roughages coarsely.

34. Ground hays are, as a rule, quite dusty and may not be consumed readily.
Adding moisture helps.
Chopping produces a physical texture of a more desirable nature for ruminants or horses than does grinding.
Chopped hay does not lend itself as well to incorporation into mixed feeds as does ground hay.

35. Figure The effect of baling (left), grinding in a hammer mill (center), or grinding and pelleting (right) on the volume of alfalfa hay after processing. Each pile contains 5 lb of hay.

36. ROUGHAGE PROCESSING Dried, Dehydrated Roughages
Alfalfa meal is produced in the U.S., mostly for export, and some is produced in Europe.
Dehydrated alfalfa, Bermuda grass, and other forages are harvested at an early stage of growth when protein content is high and the fiber content relatively low.
Also a high content of carotene and xanthophylls.
Cost is relatively high, so it is used in limited amounts for poultry or swine as a source of carotene, vitamins, or unidentified growth factors.

37. ROUGHAGE PROCESSING Dried, Dehydrated Roughages
Figure One example of a commercial dryer used for drying and dehydrating feeds.

38. EFFECT OF PROCESSING ON NUTRITIVE VALUE - Heating
dry a feedstuff to a point allowing storage without refrigeration, use of preservatives, or ensiling.
Reduce microbial content (sterilization)
Alter the chemistry (denature proteins, gelatinize starch, inactivate toxins)
With regard to proteins, excessive heating in the presence of sugars may result in browning.
As a consequence of the Maillard reaction, lysine reacts with the sugars and becomes partially unavailable to the animal.

39. NUTRITIVE VALUE - Heating
Overheating fish or animal proteins makes them less efficient.
Heating of cereal grains to a moderate degree for short periods of time may result in a slight improvement in protein utilization for ruminants.
But little if any improvement for nonruminants.
Heating legume seeds results in an improvement in protein quality, degrading anti-quality factors.
Soybeans
Increase the metabolizable energy value
Reduces solubility of soy protein for less degradation of protein in the rumen.

40. Nutritive Value - Heating
In cereal grains, heat, especially with moisture, results in partial gelatinization of the starch.
More efficient utilization of grains, particularly if mechanical rupture of starch granules takes place, especially for ruminants on high-grain diets.
Any treatment that increases exposure to air, heat or light normally results in some deterioration of most of the vitamins.
Fat-soluble vitamins and thiamin, pantothenic acid, folic acid, and biotin are particularly susceptible to destruction by heat and light.

41. NUTRITIVE VALUE - Grinding and Pelleting
Grinding results in a substantial reduction in particle size and exposure of much more surface area to the action of chemicals, as well as to the digestive juices.
Storage of ground grains or other feedstuffs results in destruction of readily oxidized nutrients.
Unsaturated fats, especially in the presence of trace minerals such as iron and manganese.
Digestibility of nutrients in pelleted feeds is usually increased when retention time in the digestive tract is the same.

42. HIGH-MOISTURE GRAIN
Harvesting grains earlier may avoid losses to bad weather or, in the case of sorghum grains, large amounts of damage from birds.
Early-harvested corn or sorghum may be expected to have a moisture content of 25% to 30%.
It is then necessary to dry, ensile, or treat them with chemicals if the grains are to be stored.
Early harvested grain requires less energy to grind or roll, and are quite palatable to livestock.
Protein & starch fractions are more soluble and more completely digested, or digested at a more rapid rate by ruminants.

43. Economics of Processing
Relatively higher energy costs have increased interest in minimizing feed processing costs or obtaining maximum return per unit of cost for processing or preservation.
Costs in megacalories of fossil fuel (oil, coal, gas) per ton of processed feed have been estimated and are shown at right.