For University of Illinois Extension, I'm Todd Gleason. An animal nutritionist at the University of Illinois has quantified the importance of particle size in ground feed for hogs. Grinding corn to finer particle sizes can increase its feed efficiency by up to 5 percent, says Hans Stein. "They don't gain any more, but they eat a little bit less to gain the same. So, pigs, they adjust their energy intake to a certain level. And that means if you have more energy in that corn because you've ground it finer, then they'll have to eat a little bit less, so their feed conversion is improved. That means you will have fewer pounds of feed used to produce a market hog." Stein is a swine nutritionist at the U of I. He investigated the effect of different particle sizes of ground corn when fed to pigs. The corn was ground to 800, 600, 400, and 300 microns. "And what we discovered there was that amino acids and phosphorus digestibility, that's not changed at all. Tt doesn't really matter what the particle size is, pigs are very efficient in digesting those nutrients. But when it came to starch, we saw a linear increase in starch digestibility as we reduced the particle size of corn. And the highest digestibility was with the lowest particle size of corn." This is because more starch is digested in the pig's small intestine, causing more glucose to be absorbed, and therefore increasing the amount of available energy. "And sure enough, we saw that the energy in the corn grain increased as we reduced the particle size. So a pig will get more energy out of corn, one pound of corn, if it's ground to 300 microns instead of 800 microns." And this is where the savings come into play. The feed conversion rate improves by about 1.2% for every 100 micron reduction in particle size -- a saving of, say, seven pounds of corn to finish a pig. "Or you can say if you want to formulate your diets to a certain amount of energy, then you can take some of the fat out. Because usually we use fat to have more energy, but if you have smaller particle size you can actually take some of the fat out and the pigs would do exactly as they did with more fat in the diet, just because you had a smaller particle size." There are a couple of negatives to the smaller grind: the feed does not flow nearly so well and there's an increased risk of stomach ulcers. Well, the Illinois nutritionist says hog producers should try smaller grains over time, ratcheting down 100 microns every couple of months. Rations with higher fiber contents will be most successful at the lower particle sizes. For University of Illinois Extension, I'm Todd Gleason.