González-Vega, J. C., C. L. Walk, and H. H. Stein. 2015. Effect of phytate, microbial phytase, fiber, and soybean oil on calculated values for apparent and standardized total tract digestibility of calcium and apparent total tract digestibility of phosphorus in fish meal fed to growing pigs. J. Anim. Sci. 93:4808-4818. Link to full text (.pdf)

Liu, Y. and H. H. Stein. 2015. Effect of Sal CURB on digestibility of energy and nutrients by growing pigs. J. Anim. Sci. 93(Suppl. s3):855-856 (Abstr.) Link to abstract (.pdf)

Porcine epidemic diarrhea virus (PEDV) can be spread via contaminated feed. Treating PEDV-contaminated feed with formaldehyde has been shown to prevent infection in pigs that consume the feed. However, concerns have been raised about the effect of treatment with formaldehyde on the nutritional value of feedstuffs. Therefore, an experiment was conducted to determine the effects of adding a formaldehyde-based feed disinfectant to the diet on the apparent ileal digestibility (AID) of dry matter, crude protein, and amino acids, and the apparent total tract digestibility (ATTD) of dry matter, gross energy (GE), calcium, and phosphorus in nursery pigs.

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.

González-Vega, J. C., C. L. Walk, and H. H. Stein. 2014. Effect of fiber and fat on calculated values for standardized total tract digestibility of calcium in fish meal. J. Anim. Sci 92(E-Suppl. 2):231-232 (Abstr.) Link to abstract (.pdf)

Calcium supplementation is important for swine diets because most commonly used feed ingredients have low concentrations of calcium. In a typical corn-soybean meal diet for a growing pig, the corn and soybean meal contribute only about 16% of the total calcium, with the rest coming from supplements. Apparent total tract digestibility (ATTD) values for calcium have not been reported for many common ingredients, and no values for the standardized total tract digestibility (STTD) of calcium have been reported. Therefore, an experiment was conducted to determine the ATTD and STTD of calcium in five calcium supplements.

An additional objective was to test the hypothesis that inclusion of microbial phytase in the diets increases the ATTD and STTD of calcium. Results of previous research has indicated that inclusion of microbial phytase in swine diets often increases the digestibility of calcium, but the effect of phytase on the STTD of calcium in individual ingredients has not been reported.

González-Vega, J. C., C. L. Walk, Y. Liu, and H. H. Stein. 2014. The site of net absorption of Ca from the intestinal tract of growing pigs and effect of phytic acid, Ca level and Ca source on Ca digestibility. Arch. Anim. Nutr. 68:126-142. Link to full text (.pdf)

González-Vega, J. C., C. L. Walk, Y. Liu, and H. H. Stein. 2013. Determination of endogenous intestinal losses of calcium and true total tract digestibility of calcium in canola meal fed to growing pigs. J. Anim. Sci. 91:4807-4816. Link to full text (.pdf)

Sulabo, R. C. and H. H. Stein. 2013. Digestibility of phosphorus and calcium in meat and bone meal fed to growing pigs. J. Anim. Sci. 91:1285-1294. Link to full text (.pdf)