Controlling Particle Size Can Net Dollars
By Mark Bertram, Ph.D., First Choice Livestock
With the high cost of feed in today’s market place it is important to pay close attention to factors within your control that affect the efficiency of feed utilization. A factor that is easily controlled through attention to detail is corn particle size. However, it is often overlooked and not included in a standard QA program in many feedmills. Reducing particle size results in improved efficiency because the smaller particles of the corn allow increased access of digestive enzymes. Research has indicated that for every 100 micron decrease in particle size, the efficiency of feed utilization improves by 1.5 to 2% and average daily gain improves by approximately 1%. Traditional literature has indicated that the optimal particle size is 650 to 750 microns. However, with today’s roller mills it is possible to reduce particle size to as low as 500 microns with no adverse effects on feed flowability or death loss due to ulceration, especially if the geometric mean standard deviation of particle size is kept below 2.5. The standard deviation is a measure of the variability of the particles in a sample and it appears that much of the feed bridging and stomach ulceration problems are caused by particles that are less than 250 or 300 microns.
There are several keys to consistently hitting these targets. Firstly, the mill should be measuring particle size on a daily basis, using a 2 pan quick test and adjusting the rolls as needed. Secondly, I have found that increasing the groves per inch of rollers from 6 on the top roll and 12 on the bottom roll to 7 on the top and 14 on the bottom can result in significant decreases in particle size while maintaining acceptable standard deviations. Thirdly, maintaining moisture of corn between 13 and 15% at the time of rolling will significantly help in hitting these targets. Finally, on a monthly basis, a sample should be sent to a lab for a complete particle size analysis and the lab should utilize a flow agent when conducting the test. The flow agent gives a more consistent result with a more accurate standard deviation.
Decreasing particle size from 850 to 900 microns, where many mills are currently running to 500 to 550 microns will result in nearly 40 lbs less feed used per pig over a 255 lb growth phase or a saving of over $3 per pig marketed. This significant savings can be the difference between profit and loss for many producers in today’s marketplace.
Mark Bertram is a Swine Nutritionist from Polk City, Iowa. He received his Ph.D. from Iowa State University and has been in the feed and swine production industry for 12 years. His main focuses are nutritional program design and implementation, feed quality control and production management. Mark can be reached by phone at (515) 290-2979 or email at mjbporktec@aol.com.
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