New technologies in feed production

by Emily Wilson
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Many issues are forcing innovations in the feed industry. In some cases, it is the inability to compete in economic terms, while in others, regulations from government agencies have forced changes. In all cases, adopting new concepts and technology is done to stay competitive or stay in business. Adopting change for its own sake is seldom an option.

Food safety is probably going to drive future changes in animal agriculture more than any other issue. These include control of microbial contamination (Salmonella, E-Coli, mycotoxins), pesticides and other chemical residues in feeds and ingredients and the discontinued use of growth promoters. Environmental concerns, including air pollution, water pollution, animal waste disposal and odor control will also effect plant design. Expect to see plant locations selected on environmental considerations rather than traditional livestock density.

We will see feed lines more tailored to regional demand and a growth in single species mills, aquaculture and companion animal feeds. While on-farm feed manufacturing is not a thing of the past, many producers have found that they can be more profitable by focusing on management and letting others do what they do well. Alliances formed between producers have given them leverage in feed purchases that independent producers have never had. That trend will certainly continue but will give feed manufacturers larger production runs to justify a lower selling price.

As we move into the next century, there will be more and better options for automation. Perhaps the greatest advantage of automation is the ability to generate reports. This can range from a minute-by-minute log of processing variables, inventory and daily usage reports, receipts and loadout reports, and accounting reports to such mundane items as preventive maintenance logs and schedules. We are in the "information age," and those who wish to remain in management positions must learn to be information managers as well as process and people managers.

Below is a detailed review of influential issues and changes that may be necessary to survive in the future.


Everyone has heard about Genetically Modified Organisms (GMOs). At this time, the worst case most feed mills are facing is dealing with two grain sources that need to be received, stored, ground and used separately. Those are typically corn together with grain sorghum, wheat, or barley. A few are now also dealing with high oil corn, which is not a GMO.

In the future, we may have as many as four or five GMO grains plus commodity grains that require identity preservation (IP). Imagine the confusion at receiving and within the grinding operation, bin space allocation, inventory and quality assurance programs. Today is when we should all begin planning how to deal with the situation in the future. If we wait until the IP grains are on the rail siding, chaos will reign. There are no easy answers with current feed mills. It may require new storage and grinding construction.

In new construction, flexibility should be included in the design from the start. For example, North Americans typically use pre-grind operations to prepare grains for proportioning and mixing, while Europeans normally use post-grind. If grinding takes place after weighing, that piece of the puzzle is solved. New feed mills should be built with the capability to do either pre-grind or post-grind operations efficiently.

In addition to GMOs, new byproduct ingredients will continue to find their way into feeds. Most of these will come from food processing and may be opportunity ingredients in specific areas.

High-speed unloading: If a feed mill receives bulk ingredients by rail, it will likely be necessary to have rail siding available for up to 100-car trains. Demurrage will begin 15 hours after the train is delivered and will be expensive. In many cases, companies are already in the process of building extra storage and high-speed unloading systems just to be able to get ingredients on a timely basis.

Ingredient segregation: With current analytical technology, it is possible to assay ingredients in a very short amount of time and segregate based on a critical attribute, such as protein, fat or moisture. Once segregated, nutrient variation within a given lot is reduced dramatically. This makes it possible to formulate much closer to the known nutrient requirements of the target animal and avoid wasting nutrients.

This makes obvious the need to construct storage facilities with a great deal of flexibility in mind. Specialty ingredients alone will force this issue.


Grinding: Though a trend began toward rollermill grinding, it appears that trend is reversing, and hammer mills will continue to be the grinder of choice (see World Grain, April 2002, E-Archive #52860).

Issues to watch in the future:

•Drilled vs. punched screens

•Hammer design

•Hammer metallurgy

•Air assist system design

•Noise control

•Automation and routing

•Quick change screens

•Quick change hammer gangs

There is a trend in Europe using vertical-shaft as opposed to horizontal-shaft hammer mills. One reported advantage is that air assist is not necessary or advised. The rotor design is such that its rotation creates a fan effect that forces air from the grinding chamber through the screen. An added feature is that multiple entry points are possible. In a typical split-screen hammer mill, all grinding stock enters at a single point. This leads to excessive wear just below the feed throat. With multiple entry points, wear patterns should be more evenly distributed around the grinding chamber.

Grinding is clearly one operation that should be fully automated. Everything from choosing the correct supply bin and downstream routing to automatic start-up and shut-down should be considered. Even grinding during unattended hours can be safely considered with appropriate instrumentation and control.

Proportioning systems: Current batching system technology is quite good but is sometimes difficult to maintain. There is room for improvement in several areas.

On-line reformulation: Instrumentation is currently being tested that can measure chemical components such as protein, certain amino acids, fat, moisture, fiber and starch. It will be possible to reformulate feed on a nearly batch-to-batch basis and create feeds with a great deal of precision.

Weighing accuracy: In a recent report, data on weighing errors from 14 mills involved in commercial, cooperative and integrated feed production showed that while the majority of mills are operating within reasonable limits, several were essentially out of control. In some cases, weighing errors of 200% or more were fairly common. The major deficiency noted was that small weighments were being made in large-capacity scales. A secondary deficiency found was mismanagement of batching software.

There are micro-ingredient systems available that use a loss-in-weight concept rather than net weighment into a single batching scale. This concept can be expanded to include ingredients received in tote bags or tanks. Using loss-in-weight, it is possible to envision 10 or 15 weighments going on simultaneously. This will shorten the batching cycle and provide continuous inventory reports and more weighing precision than is currently possible. Batching cycles in the range of 1 to 1.5 minutes will be necessary to keep up with the short cycle mixers of the future.

Mixing: This is a very confusing area given the trend toward very large, single mixers (12 to15 tonnes) in new single-species feed mills. I do feel that there will be a place for small (2 to 4 tonnes), short-cycle mixers, because of the need for production flexibility and high hourly throughput. For example, a 3-tonne mixer on a 1.5-minute cycle can produce 120 tonnes per hour. This is possible even today, and 1-minute cycles may be available in the future.

There are several innovations taking place in mixer design. In traditional horizontal ribbon mixers, new ribbon configurations are improving mixer efficiency. In many instances, the new ribbon design is being retrofitted into older mixers to extend the mixer’s life and reduce mixing time.

Another innovation is the vertical-shaft mixer. This is simply a vertical cylinder with a single ribbon that elevates the feed while gravity works to move the feed downward. These mixers are often found in food processing facilities but are finding use in the feed industry. With a liquid feed lance and cutting rotor, high levels of liquids can be incorporated without lumping.


The pelleting process will not be replaced in the future; however, there will be innovations made that will result in improvements in both efficiency and pellet quality. Some innovations and options are currently available but are seldom retrofitted into existing feed mills.

Conditioning-time controllers: There is no single conditioning time that is optimum for all feeds; therefore, innovations will make conditioning time a controlled variable. This may be done by shaft speed and/or pick angle control. Time will be controlled for each feed type and desired pellet quality.

It has long been recognized that conditioning resident time has an influence on conditioning and pellet quality. Some innovations from European suppliers have been introduced recently.

First is the conditioner angle. Nearly every conditioner is installed in the horizontal plane. By adding at the back of the conditioner a hinge, a mechanism to raise the front of the conditioner and flexible feed and discharge spouting, it is possible to have nearly infinite control on resident time. Under normal operation, conditioning would begin with the conditioner in the horizontal plane. Once stable operations are obtained, the conditioner can be inclined to extend retention time to the desired level.

Also introduced was the pick (paddles) angle adjustment, a new device that allows the conditioner pick angle to be changed during operation. In this case, the conditioner shaft is hollow and contains the mechanism to rotate the pick angle at any time. Again, pelleting is initialized with a "standard" conditioner paddle angle. Once stable operations are obtained, the angle can be adjusted to increase or decrease retention time.

Steam or mash weirs (dams) are another innovation. A relatively simple, but effective, modification to the conditioner is to install "weirs," or plates, to block the exit of either steam (covering the top two-thirds of the conditioner) or mash (covering the bottom two-thirds of the conditioner). The top plate prevents the steam from traveling the length of the conditioner and exiting without being in contact with the mash. The bottom plate acts as a dam forcing the picks to elevate the conditioned mash over the plate opening. In this case, drug residue is a serious concern because 50 to 200 pounds of feed will be left in the conditioner at the end of a run; however, both technologies offer a partial solution to conditioning problems.

Moisture control: There are moisture monitoring and control systems available today; however, improvements are needed in accuracy and reliability. We will be able to "dial in" a desired mash moisture just like controllers handle mash temperature today.

Formulating for pellet quality: The industry is getting close to having the ability to formulate for pellet quality just as we formulate for amino acids, minerals, energy and so on. This is a more difficult challenge because pellet quality does not respond in a linear manner to increases or decreases in specific ingredients. With enough data, pellet quality should be predictable.

On-line roll adjustment: This is an option that is available but is widely viewed as too expensive to justify. A recent experience with a pellet mill so equipped convinced me that this is not the case. After a severe pellet mill plug, the rolls were backed off and the pellet mill restarted and cleaned out without opening the door. It took less than 5 minutes.

There is likely no single roll setting best for all feeds. On-line roll adjustment will solve that dilemma.

Pressure Pelleting: A new pellet mill design is being developed in which mash is conditioned under slightly elevated steam pressure to reach a temperature above 212°F (100°C). Early results for pellet quality and broiler performance are encouraging. A concept machine is in operation at a broiler feed mill with a production machine to be installed also.

Universal pellet cooker (UPC): The UPC is closer to an extruder than a pellet mill, but the product resembles a pellet in appearance. Extremely high pellet quality is attainable with a UPC, and it will find its way into many specialty applications such as aquafeeds, starter diets and high margin items such as pet foods.

Expanders: Using high-temperature/short-time conditioners has found varied acceptance. While improved pellet quality is nearly always obtained, projected improvements in animal performance have not always occurred. Maintenance and operating costs have been a shock to some who have installed expanders. Others have discovered health problems (ulcers) in pigs fed expanded feeds.

Some companies are exploring the possibility of using only expanders and no pelleters. Density and flow problems have been observed, but performance seems to be equal to that of pelleted feeds.

Coolers: Counterflow coolers are most common. However, finished product moisture control has not been solved by any current cooler design. I feel coolers of the future will be equipped with moisture sensing and control and will be able to dry as well as cool products to a safe level. This will require both heating and cooling zones, airflow control and sophisticated control schemes from vendors.

Post pellet additive application: This area is presenting an immediate challenge with the introduction of phytase enzymes and other heat sensitive additives. (See related article on page 28.) There is a real challenge in being able to apply 50 or even 25 grams of active material uniformly on a tonne of feed. We simply cannot do this as we currently apply fats and oils at 20 to 80 pounds per tonne.

Again, a lot of technology exists but is often judged to be too expensive to retrofit into an existing facility. This concept, however, should be incorporated in all new designs and construction. Loss-in-weight systems, or weigh belt or weigh screw feeders, have the ability to control pellet flow and signal a controller so that the correct amount of additive can be applied.

I feel phytase is the beginning of the low-inclusion, heat sensitive additives. Other enzymes, drugs, vitamins and biologicals may require even higher levels of accuracy. My advice is to prepare now.


We have a bit of a conflict between feed mill managers and nutritionists on the subject of animal diets. Nutritionists would like to have 12 to 20 different feeds for the life cycle of a pig or turkey and 8 to 12 for a broiler. Most feed mill managers would like to have one feed per animal species. Therein lies the dilemma. The more formulas produced, the less efficient the feed mill in terms of production and loadout.

A few companies are experimenting with the concept of producing two or three basic formulas and then blending at loadout to create the correct feed for each stage of growth. It is theoretically possible to produce three feeds and create an infinite number of feeds to match the nutrient requirements of the target animal precisely at any stage of life.

But there are practical problems. Blending requires extra weighment or proportioning devices. Accuracy is also an issue, and degradation of pellet quality needs to be addressed. Uniformity of the finished blend has to be at least as good as the original feed. This is, however, a solution that will result in optimized feed mill performance and feeds that closely match the requirements of the target animal.

It is impossible to predict how feed mills will change in the 21st century. There will be a great number of options, and the better informed we are, the better choices will be made. Feed mills will be influenced by food safety and environmental issues as well as livestock production efficiency and economics. Trends set in Europe influence the global feed industry, so information from that region may foretell things to come.