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Feed cost is of significant importance in animal production, since it represents around 70% of the cost of live animals or derived products. Therefore, maximizing the use of feed, improving the productive efficiency index by improving feed conversion and reducing the negative impact of microorganisms, is essential for economic and environmental viability. One of the ways to improve this efficiency is through heat treating the feed.
The objective of this article is to indicate some referential parameters of operation for the different processes, with an emphasis on pelletizing, expansion and for formulas classified as having high starch content (broilers and fattening pigs), in order to improve the results with the use of these processes.
It is a very controversial topic where doubts and uncertainty appear, both in companies and in the different scientific works available. In addition, there are also several aspects that need to be studied in greater depth. However, here we will try to offer some practical and operational guidelines.
Main variables worked in heat treatments:
These variables can be worked with different correlated intensities and will basically depend on the type of feed treated, the defined objectives and the structure of the processes.
Main heat treatments used in the manufacture of balanced feeds:
Thermo-conditioning: Heat treatment without physical format change. It consists of heating the feed, generally via indirect heat; and its basic objective is to sanitize it, that is, to reduce or eliminate microorganisms. More often used for poultry breeders and commercial layers in order to maintain the grain size advantage.
Pelletizing: It is the most widely used process in the feed industry, especially for economically exploited animals (pigs, poultry, cattle, …). In this process, the powdered feed is transformed into granules (pellets). It is the best known process and where there are fewer doubts about economic and operational viability.
Expansion: This process uses the variable pressure with greater intensity and is normally used as a conditioning intensification process in pelletizing lines. It is also used to heat treat (expand) individual or joint products such as corn, soybeans, wheat, cakes, etc.
Extrusion: It is the most complex process and works the variables with greater intensity. Depending on its cost, it is generally not economically viable, except for pet and fish food.
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