Trends and new technologies for feed milling
The development of feed production technology has undergone a subtle shift during the past ten years. In general, development of primary machinery has slowed with changes principally in scale rather than method. This paper will describe that the most important developments are those on the fringe of these core processes. They can be termed smart manufacture, obtaining the best outcomes through optimizing technologies.
Much of the developing milling technology is used widely in other industries. The major aspects of new trend in feed processing will be stated in the order they appear in most post grinding feed mills.
For weighing and blending, smarter computer systems and cheaper load cell technology now involve greater use of weighers in plant to control flows, monitor process and weighing rather than metering liquids. Demands for greater traceability and higher efficiency with increasingly smaller work forces are the driving force.
For grinders, smart developments in this area are those aiming to achieve the best particle size. Pre-grinding mills, however have largely been superseded with post grinding mills on the grounds of high capital cost.
The past ten years have seen the development of slow speed grinders and rollers in post grinding, especially in the poultry feed sector, accompanied by pre-screening.
But in terms of optimal particle size, there is no change to size reduction of separate raw materials.
As for conditioning, many different conditioners have been developed during the past seven years. In the late 90Â¡Â¯s research found that single short-term conditioners with sufficient meal temperature from steam injection achieved satisfactory microbiological kill rates.
This has led to a plethora of new conditioning machines (see Figure 1 as example), all generally increasing the time of conditioning to many minutes. This however carries potential problems of nutritional damage to raw materials and additives (Garland, 2005)
Common conditioning temperatures used in Australian feed mills around 90 deg C with normal press conditioners exceeding the minimum requirement.
Smart conditioning involves working with liquids to achieve lower energy inputs, both in conditioning and downstream at the presses, expanders and extruders. Recent developments in emulsifier technology indicate the possibilities for improved gelatinisation and homogeneity in providing optimum digestibility of feed.
For pelleting, attention was given to effective batch sizes in pelleting presses.The start up and shut down phase of a feed batch is the most risky from a bio security aspect. Ideally, feed from each end of the batch should be recirculated or rejected, and this would be too high a penalty if the press is over sized. Better use of existing presses can be made with advances in liquid conditioning techniques.
For mixing, dry mixing is acceptable up to a point, but different particle sizes means good dispersion only at point of mixing. Subsequent handling and storage even for short periods often results in separation. The solution is to extend liquid ingredients and liquid combinations to allow significantly increased dispersion.
Other trends in feed milling are:
1. Liquid technology
2. Developments in feed hygiene
3. Computer technology
4. Mill security
5. Staff training and innovation
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Article made possible through the contribution of the Australian Poultry Science Symposium (APSS) 2006.