By: Casey Neill

This past month, Pipestone Grow Finish held a Nutrition conference.  Several nutritionists  including Dr. Joel DeRouchey from Kansas State University, Dr. John Patience from Iowa State Universtiy, Dr. James Usry from Mironutrients, and Dr. Charles Stark from Kansas State University Department of Grain Science  presented.  Grow Finish clients were excited to spend an afternoon learning about feed manufacturing, swine diets and feed efficiencies.

Dr. Stark presented on feed manufacturing, with some valuable takeaways worth reviewing.  You can have the best nutritionist on staff, who formulates the perfect diet on paper, but if it’s not mixed properly the diet will not perform.  Dr. Stark focused on four main areas of concentration for a feed mill: roller mill grinding, particle size analysis, statistical process control, and mixer uniformity testing.  Each of these areas improve the accuracy of the diet, and overall improves feed efficiency.

Let’s start with roller mill grinding.  The two most common roller mills used in the feed industry is the two high pair roller mill, and the three high roller.  The two high pair roller can grind corn down to 500 microns, whereas a three high roller grinds all the way down to 350 microns.  Grinding to a uniform particle size increases feed efficiency and feed flow ability.  One way you can maintain uniform particle size is to make sure you have a scalper (seen on right.)  Most roller mills are equipped with one, but the scalpel will ensure that large cobbs, stalks, and rocks are removed that the combine didn’t catch.  If not removed, these foreign objects can cause a larger separation between rollers, allowing larger corn particles to pass through which in turn will decrease your feed efficiency. As a producer you need to weigh the pros and cons of a roller mill.  The advantages are low energy consumption and uniformity of particle size, while the disadvantages are high investment cost, and complicated operation and maintenance.

Another way you can increase feed efficiency is through Particle Size Analysis.  You may be operating everything down to a tee – but is your grinder working properly?  Before sending your particle size sample off to be tested, it is important to understand what method the lab is using.  Labs use a 13 sieve system that analyzes the particle size, coming back with a standard deviation, and an average micron size. However the numbers you get back may alter depending if the lab uses a flow agent or not.  Using a flow agent will allow the particles to flow easier through the 13 sieves, which in turn will show a lower particle size.  I’m not here to argue whether one practice is better than the other, but simply that you (as the producer) should be aware of the difference when reviewing your Particle Size Analysis.  I also recommend staying with the same lab to more effectively analyze present vs. historical particle size results – otherwise it may be difficult to decipher which changes occurred because of different lab practices vs. an actual change in your operation.  Once you have your preferred method of testing and lab chosen, you can use the Particle Size Analysis to determine if your grinder is maintaining uniform particle size.

Batching is the ground work of a good recipe.  If you end up with too much limestone and not enough vitamins your diet isn’t going to perform optimally.  Installing a Variable Frequency Drive will allow you to precisely measure ingredients.  As you start to near the end of one ingredient, the auger will slow down until the measurement is complete, as opposed to running full speed until it is complete and then “shut off” while pounds of that ingredient continue to pour out and offset the formula.  Another tool to consider using is a Statistical Process Control chart (seen on right), which will help you track weight trends.  Watching these trends will help improve accuracy of the computer batching system and will be an indicator if ingredients or batches are consistently running short or heavy.

The last point Dr. Spark highlighted in his talk was mixing.  Often, when we talk about mixers we talk in terms of tons.  It’s a 3 ton mixer or a 5 ton mixer.  But instead of focusing on tons, we should really focus on the volume or cubic feet a mixer can hold, for example, referring to a 58 cubic feet mixer or a 30 cubic feet mixer.  The reason being is a corn soy diet is going to be heavier but take up less cubic feet than a diet with a lot of fiber, which will weigh less, but take up a lot more room in the mixer.  The mixer you have may be able to hold the weight of a high fiber diet, but may not have the space or volume needed to mix the diet properly.  It is important to understand the volume needed to mix your diet accurately. One test to determine if your mixer is properly mixing your diet is to do a mixer efficiency test. This test is done by taking 10 samples of feed from one batch and sending to a lab. The lab will test all 10 samples for sodium or zinc and figure the variation from sample to sample. That variation should not be greater than 10%. This test should be done twice a year.

To summarize: roller mill grinding, particle size analysis, statistical process control, and mixer uniformity testing are areas to seek improvement in feed efficiency.  As with all business decisions, weigh the pros and cons of each investment and determine if it is right for your operation.  Should you have any questions about any of the topics covered in this article, feel free to contact me a cneill@pipevet.com and I would be more than happy to discuss a plan for your operation or point you in the right direction.