Pellets: Why and How?

Have you wondered WHY we at Hunt & Behrens, Inc make pellets for our horse, swine, poultry, and cattle feeds? I’ve included a very informative excerpt from a pellet mill manufacturer that clearly lays out the benefits and reasoning behind the pelleting process.

If you are a VISUAL Learner, here is an outstanding video animation of the pelleting process

The following from the California Pellet Mill Technical bulletin: The Pelleting Process
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 andusually result in improved feeding results when compared to the unpelleted feed.

Pellets are generally formed with diameters from 10/64” to 48/64” and will be somewhat longer than the diameter. A small part of the production of large pellets, 32/64” 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 1-1/4” to 1-3/8”. In most cases where particle sizes smaller than 10/64” are desired, it has been found to be more satisfactory from the standpoint of economics to produce a
10/64” or 12/64” 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
(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 (5.06 lb. per day of pellets vs. 5.02 lb. per day of mash), yet the pellet fed pigs gained a quarter of a pound per day more weight than did the mash fed animals (1.76 lb. vs. 1.54 lb. of gain per day). 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 averageamount of feed required for each pound of gain. The pellet fed hogs consumed 2.87 lb. of feed per pound of gain while the mash fed hogs needed 3.27 lb. to make a pound of weight gain.
Pellet fed hogs not only gain faster but they do it with less feed for each pound 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.

In 1978, there were 9,977 feed mills registered with FDA producing 78.2 million tons of feed annually; about 60% is pelleted. Not all feed mills, of course, are equipped to pellet feeds. In
1958, these mills produced 40 million tons of feed and about 55% was pelleted. In 1968, about 70% of all commercial poultry feed produced in the United States was pelleted. In the Midwest,
almost 80% of all manufactured feed is pelleted, crumblized or cubed.

The process of producing feed pellets can roughly be described as a plastic molding operation of the extrusion type. Feed ingredients are made up of various compounds such as proteins, acids,
sugars, fibers, and minerals. These products can be softened (conditioned) by the addition of heat and water. When sufficiently controlled compression is applied to the “conditioned” feed
ingredients, they will form a dense mass, shaped to conform to the die against which they are pressed. When the heat and moisture is again withdrawn (dried and cooled) as to withstand
moderately rough handling without excessive breakage and has retained or enhanced its nutritive value.

In modern feed mills, the ingredients are usually stored in bins above a weighing system composed of one or more scales. Those ingredients which are of coarse texture, such as whole
grains and other fibrous materials, are ground into a fine meal to facilitate the pelleting and mixing process. Weighted quantities of each ingredient (either as a batch or continuously) are
thoroughly mixed (either in a batch mixer of a continuous flow mixing unit) and then conveyed to a bin above the pellet mill. Some manufacturers have installed systems to grind all of their
premixed materials prior to entering the pellet mill. Data is not available which indicates this has been an advantage or disadvantage on a consistent basis as far as durability is concerned.