Merriman, L. A. and H. H. Stein. 2016. Particle size of calcium carbonate does not affect apparent and standardized total tract digestibility of calcium, retention of calcium, or growth performance of growing pigs. J. Anim. Sci. 94:3844-3850. Link to full text (.pdf)

Soy protein concentrate is produced by aqueous ethanol extraction of water-soluble carbohydrates from soybean meal, followed by heat treatment. The ethanol extraction process removes soluble carbohydrates, leaving a product that contains at least 65% crude protein. Because soy protein concentrate contains reduced levels of oligosaccharides, trypsin inhibitors, and lectins compared with conventional soybean meal, it can be used in diets for weanling pigs.

Reducing the particle size of soybean meal can increase amino acid digestibility due to the increased surface area for enzymes to work on. However, there are no known data on the effect of particle size on amino acid digestibility in soy protein concentrate. Therefore, an experiment was conducted to determine the digestibility of crude protein and amino acids in soy protein concentrate ground to three different particle sizes and to compare these values to values for soybean meal and fish meal when fed to weanling pigs.

Rojas, O. J. and H. H. Stein. 2015. Use of feed technology to improve the nutritional value of feed ingredients. Page 23 in Advances in Animal Nutrition in Australia, Armidale, New South Wales, Australia, October 26-28, 2015. (Abstr.) Link to abstract (.pdf)

In poultry, the particle size of inorganic calcium sources has been shown to affect calcium retention and eggshell quality. However, little is known about the effect of particle size of inorganic calcium fed to pigs. Results of a previous experiment conducted in the Stein Monogastric Nutrition Lab indicated that calcium digestibility and retention were not affected by the particle size of supplemental calcium carbonate. A follow-up study was conducted to test the hypothesis that calcium carbonate particle does not affect growth performance by weanling pigs.

Rojas, O. J. and H. H. Stein. 2015. Use of feed technology to improve the nutritional value of feed ingredients fed to pigs. J. Anim. Sci. 93(Suppl. 2):61 (Abstr.) Link to abstract (.pdf)

Rojas, O. J. and H. H. Stein. 2015. Impact of particle size reduction on feed cost and feed efficiency. Pages 207-227 in Proc. Banff Pork Seminar, Banff, AB, Canada, Jan. 20-22, 2015. Link to full text (.pdf)

Rojas, O. J. and H. H. Stein. 2014. Effects of reducing the particle size of corn on growth performance of weanling pigs. J. Anim. Sci. 92(Suppl. 2):158 (Abstr.) Link to abstract (.pdf)

Rojas, O. J. and H. H. Stein. 2013. Reducing feed particle size may enhance performance. Page 12 in National Hog Farmer, December 15, 2013. Link to full text

Grinding of feedstuffs to small particle sizes is a low-cost way to increase their energy and nutrient digestibility. Currently, nutritionists recommend feeding corn ground to an average particle size of 650 to 700 µm. However, it may be advisable to formulate diets containing corn ground to smaller particle sizes due to the greater metabolizable energy (ME) values of these diets. A previous experiment conducted by Rojas and Stein at the University of Illinois demonstrated that when diets are formulated to contain the same amount of metabolizable energy, feeding diets containing corn ground to different sizes to weanling pigs did not have a negative effect on growth performance.

An experiment was conducted to test the hypothesis that when diets are not adjusted to contain equivalent amounts of metabolizable energy, weanling pigs fed diets containing corn ground to smaller particles sizes will have an improved gain to feed ratio relative to pigs fed corn containing corn ground to larger particle sizes.