What is the purpose of pelleting？
Pelleted feeds have been defined as “agglomerated feeds formed by extruding individual ingredients or mixtures by compacting and forcing through die openings by any mechanical process”. Basically, the purpose of pelleting is to take a finely divided, sometimes dusty, unpalatable and difficult-to-handle feed material and, by using heat, moisture and pressure, form it into larger particles. These larger particles are easier to handle, more palatable and usually result in improved feeding results when compared to the unpelleted feed.
Pellets are generally formed with diameters from 2.2mm to 18mm and will be somewhat longer than the diameter. A small part of the production of large pellets, 12mm and above in diameter, is produced in other than cylindrical shapes; they may be triangular, square or oval and, in some cases, may exceed the maximum dimension indicated above. The largest diameter usually found is rarely greater than 25mm. In most cases where particle sizes smaller than 4,0mm are desired, it has been found to be more satisfactory from the standpoint of economics to produce a 4,0mm or 5,0mm pellet and reduce it into the desired particle size by means of crumbling.
Almost all livestock feeders agree that animals make better gains on pelleted feed than a meal ration. The most logical reasons are that (a) the heat generated in conditioning and pelleting make the feedstuffs more digestible by breaking down the starches, (b) the pellet simply puts the feed in a concentrated form, and (c) pelleting minimizes waste during the eating process. When pelleted feed is fed, each animal receives a well-balanced diet by preventing the animal from picking and choosing between ingredients. Tests have shown that most animals, if given the choice between the same feed in pellet or mash form will prefer the pellets.
By combining moisture, heat and pressure on feed ingredients, a degree of gelatinization is produced which allows animals and poultry to better utilize the nutrients in these ingredients. Feed conversion will be improved. These advantages are particularly noticeable in the broiler industry.
The feeding merits of pelleted feeds over the mash form have been repeatedly demonstrated in the feeding of swine. One state college reported the results of an eight week swine feeding test in which pelleted feed performance was compared against the same feed in mash form.
This test gave the following results:
All animals, on the average, consumed the same amount of feed (2.30kg. per day of pellets vs. 2.20kg. per day of mash), yet the pellet fed pigs gained a 11 grams per day more weight than did the mash fed animals. Since the pellet fed hogs gained more while eating the same amount, it is evident that pelleting causes the feed to be utilized more efficiently by these animals. This is shown in the comparison of the average amount of feed required for each kilogram of gain. The pellet fed hogs consumed 600 grams of feed per kilogram of gain while the mash fed hogs needed 1,47kg to make one kilogram of weight gain.
Pellet fed hogs not only gain faster but they do it with less feed for each kilogram of weight increase. Pelleting prevents the segregation of ingredients in a mixing, handling or feeding process. By feeding a pelleted feed, the animal is more apt to receive a totally mixed ration than one that has separated through these processes. It also prevents waste. Bulk density is increased, which enhances storage capabilities of most bulk facilities. Shipping facilities are also increased, thereby reducing transportation costs. This is particularly evident in such fibrous ingredients as alfalfa, gluten feed, oat hulls, rice, bran, etc. A better flow and handling characteristic of pellets is one of the least mentioned advantages but probably the most important, particularly as it relates to dairy farmers