Technology offers unique benefits in animal nutrition
Animal breeders are aware of the fact that feeding animals with pellets instead of other types of feeds come with great benefits such as the absence of feed separation, reduced feed wastage, increased feed intake, improved feed hygiene and possibility to use low-cost ingredients.
However, on the other side, pelleting means increased energy and processing costs in the animal feed production plant, which is eventually transferred to the farmer. In most cases, farmers have to ask themselves whether the benefits of pelleting compensate the increased costs.
Thankfully, advances in technologies are allowing feed pellet manufacturers to produce high quality pellets at the lowest possible cost and thus giving farmers an opportunity to affordably access this valuable feed.
In this article, we explore feed pelleting, its importance in animal nutrition, and ways in which technology is improving pellet quality while making efforts at driving down costs.
Getting it right
Feed pellets are not a bullet answer to animal nutrition needs. Arthur vom Hofe, CPM Europe’s Segment Manager Feed & Oilseeds notes that there is no definitive answer to the question as to whether feed pellet is super to other nutrition types such as mash feeds.
“This choice can be determined by many factors such as animal’s type, physiology, age and nutritional needs. Even the cost/performance balance is a determining factor,” Hofe explains. Stefan Hoh, Head of Market Segment Feed Milling and Premix at Bühler Group affirms this. Hoh notes that different animals will need feed pellets at different stages of their growth. “For broilers, it has been proven that pelleted or granulated feed leads to a better performance in the starter phase of growth as compared to mash feed. However, in their middle and final fattening stage, the performance is improved by providing feed as meal.”
When it comes to pigs and poultry, different feed forms (meal, pellets, or granules) can be found. However, livestock trials have shown slightly improved feed conversion rates for pigs fed with pellets, as compared to control groups fed with mash or pellets of lower quality, respectively. When it comes to cattle and dairy cattle feed, pellets offer superior benefits that other feed types. “Cows consume pellets more rapidly than other forms of feed. This is important because eating may have a limiting effect on milk production,” adds Hoh.
Quality matters
When it comes to pellet quality, the particle size is very important. Fine particles act like a glue and form a better and tighter framework due to their larger overall surface area, strengthening the cohesive forces. Coarse particles are however a source of pellet fracture because they have a smaller surface area, which means that less liquid and solid bridges can be formed on their surface. Good quality pellet should however not have a higher percentage of fines present as this has a negative effect on growth rate and feed efficiency.
Hardness has for a long time been used to determine pellet quality but pellet durability has taken over as the standard for quality as it is regard by many industry experts today as a better measure. To accurately measure pellet durability, the Holmen test is used. With this test, 100 g of pellets is placed in a chamber, blown about 60 to 120 seconds by a jet of air, and then weighed, giving a direct read of pellet durability. Fines are removed during the blowing process.
Pellet quality is not only made in the pellet mill. Many variables from the ingredients and formulation, and process and technology used affect the quality of the final product.
Regarding the ingredients and formulation, there are feedstuff materials that pelletize well and produce a durable pellet, and there are others that won’t.
“While cereal grains make up a major part of most feed formulas, fats and oils, being present in much smaller amounts can have the same, or even a much greater impact on pellet quality,” says Hoh. “For high-fat formulations, better pellet quality can be expected when fat is bound in the raw materials compared to adding fat as a liquid in the conditioner.”
Corn and raw fiber with a high share of lignin are also known to deteriorate pellet quality. Wheat and raw fiber with a high share of cellulose are on the other hand known to promote pellet quality. Striking a balance between these ingredients thus becomes key during the pellet production process.
While cereal grains make up a major part of most feed formulas, fats and oils being present in much smaller amounts can have the same, or even much greater impact on pellet quality
Process considerations
When it comes to the process and technology, both Hoh and Hofe agree that the conditioning process is of utmost importance.
“The conditioning process, where usually steam and sometimes other liquids are added, is one of the most determining parameters for the pellet mill performance,” Hofe says. His peer from Buhler adds that moisture content and temperature of the mash at the press inlet are decisive factors at this stage of the production process. Both are greatly influenced by the quantity and characteristics of the steam during the conditioning process. “As rule of thumb, the pellet quality can be improved by increasing the conditioning temperature, while there is a trade-off at temperatures above 85 °C, where little to no further improvement of the pellet quality can be expected,” Hoh explains.
A pellet die, which is a tool used to form thin cylindrical pellets from a powder using a pellet press, can also have an impact on pellet quality. “When it comes to die specifications, the ratio of hole length and hole diameter, as well as the dwell time in the die, are of great importance,” Hoh explains. “Other determining factors are the feeding rate, the distribution of the mash in the pelleting chamber, as well as the roll gap.”
To ensure an effective process, all critical parameters of the pelleting process from motor load to, throughput, temperatures, and wear should therefore be constantly monitored. An integrated process line or plant control system can be beneficial in this regard. It’s also important to remember that the pellet production design might be okay and all parameters followed but if the pellet is not properly cooled and conveyed afterwards the potential great pellet can lose its class again. “Even the sifting and storage of the pellets contribute to the final quality of the pellet,” Hofe adds.
With size having an enormous effect on pellet quality and ultimately on animal performance, there has also been a shift in how feed pellets are being produced to align with needs of different animals. “Customers want more control of the particle size in the grinding process but still want a good pellet even with courses particles,” Hofe says. To achieve the right pellet size, advanced in-line sensors for monitoring the particle size have emerged and gained great interest from customers.
Technological advancements
In the constant strive to achieve best feed efficiency, the industry has seen many developments in optimizing feed production. The pelleting process has seen the introduction of tools that are able to control the amount of energy put in by the pellet mill.
A number of technology providers have introduced new tools to monitor critical parameters of the pelleting process, giving the pellet mill operator the opportunity to have a reliable and flexible pelleting process, producing optimal pellet quality with the lowest energy usage.
Reducing energy costs not only drives down costs but enhances the environmental credentials of the feed industry. This has become important as climate change pushes feed manufactures and breeders into adopting climate smart technologies to reduce their impact on the environment.
The high level of safety being required of animal feeds nowadays has seen technology providers provide new tools to improve safety and hygient of the feed. For example, Bühler’s Hymix Plus tool provides conditioning solution that enhances feed hygiene by ensuring 100% of the feed mash being heated up to the desired target temperature. The CPM Hygieniser also helps enhance feed safety by ensuring that all material (even the first kilo) processed by the CPM Hygienic system has reached the required temperature and retention time. “This ensures the desired Salmonella reduction for even the most demanding breeder applications,” Hofe explains.
For the pellet mill itself, we can see a clear trend towards the (partial) automation of machine features and parameters, such as the use of automatic roll gap adjustment and sensors for monitoring roll slippage. Hofe describes this as the “smart pelleting” control philosophy where AI data technology is used not only to achieve optimal process conditions at lowest operational costs but also achieve a most reliable process due to monitoring of the machine condition.
Partial automation and use of AI in pellet processing is expected to continue gaining prominence as raw material costs continue to soar, leaving manufacturers with process optimization as the only option to keep feed pellets costs low.
Parting shot
Feed pellets play a huge role in animal nutrition and technology has evolved overtime to optimize the pellet production process for both quality and affordability aims.
When it comes to pellets, there is no one size fits all. Different animals have different specifications and knowing this is key to optimizing feed pellets to deliver the best level of nutrition to animals. When it comes to production, technological advancements have greatly improved the process and today we have different profiles for different nutrition needs.
As continuous scientific research brings new insights and new raw materials find their way to the protein chain, improvements will be required to be made to the currently available production technologies to align with future realities. As Buhler Feed Milling and Premix segment lead at Buhler Stefan Hoh would say, the goal of innovation in this sector is “to create the best experience, yield and profit possible for feed producers.”
This feature appeared in the August 2022 issue of Milling Middle East & Africa. You can read this and the entire magazine HERE
