Particle size is an important consideration for some feed ingredients in pig diets. Reducing the particle size of cereal grains and soybean meal in diets fed to pigs improves digestibility of energy, amino acids, and other nutrients, because feed ground to smaller particle sizes has more surface area on which digestive enzymes can work.
The particle size of inorganic calcium sources has been shown to affect calcium retention in poultry. Particle sizes of 1.00 mm or greater are recommended to optimize calcium retention and eggshell quality in laying hens, but coarse particle sizes result in reduced calcium retention in broiler chicks. However, little is known about the effect of particle size of calcium sources fed to pigs. Therefore, an experiment was conducted to test different particle sizes of calcium carbonate and determine which size optimizes calcium digestibility and retention by growing pigs.