It is important to include calcium and phosphorus in the diets in the proper proportions because the excess or deficiency of one mineral may affect the utilization of the other. Calcium requirements in the 2012 NRC are based on a model, which used a 2.15 ratio of total calcium to standardized total tract digestible (STTD) phosphorus. An optimal ratio of STTD calcium to STTD phosphorus has not been reported because not enough data exist on the standardized total tract digestibility of calcium. However, recent studies conducted by the Stein Monogastric Nutrition Lab have determined values for STTD calcium for several calcium sources. With these data, it is possible to determine the requirement for STTD calcium. Therefore, an experiment was conducted to determine the requirement of STTD calcium to maximize growth performance and bone ash in 11 to 25 kg pigs.

Maison, T., Y. Liu, and H. H. Stein. 2015. Apparent and standardized total tract digestibility by growing pigs of phosphorus in canola meal from North America and 00-rapeseed meal and 00-rapeseed expellers from Europe without and with microbial phytase. J. Anim. Sci. 93:3494-3502. Link to full text (.pdf)

Parr, C. K., Y. Liu, C. M. Parsons, and H. H. Stein. 2015. Effects of high-protein or conventional canola meal on growth performance, organ weights, bone ash, and blood characteristics of weanling pigs. J. Anim. Sci. 93:2165-2173. Link to full text (.pdf)

Liu, Y., O. J. Rojas, and H. H. Stein. 2015. Effects of extrusion of corn and oats on the digestibility of energy and nutrients in diets fed to pigs. J. Anim. Sci. 93(Suppl. 2):134-135 (Abstr.) Link to abstract (.pdf)

Lowell, J. E., Y. Liu, and H. H. Stein. 2015. Comparative digestibility of energy and nutrients in diets fed to sows and growing pigs. Arch. Anim. Nutr. 69:79-97. Link to full text (.pdf)

Kim, B. G, Y. Liu, and H. H. Stein. 2014. Energy concentration and phosphorus digestibility in yeast products produced from the ethanol industry, and in brewers’ yeast, fish meal, and soybean meal fed to growing pigs. J. Anim. Sci. 92:5476-5484. Link to full text (.pdf)

Rojas, O. J., Y. Liu, and H. H. Stein. 2014. Concentration of metabolizable energy and digestibility of energy, phosphorus, and amino acids in lemna protein concentrate fed to growing pigs. J. Anim. Sci. 92:5222-5229. Link to full text (.pdf)

Liu, Y., M. Song, F. N. Almeida, S. L. Tilton, M. J. Cecava, and H. H. Stein. 2014. Energy concentration and amino acid digestibility in corn and corn coproducts from the wet-milling industry fed to growing pigs. J. Anim. Sci. 92:4557-4565. Link to full text (.pdf)

Soybean meal is the most common source of protein in swine diets in the United States. However, conventional soybean meal contains antinutritional factors such as antigenic proteins, oligosaccharides, lectins, and trypsin inhibitors that limit its use in diets fed to weanling pigs. Methods of processing soybean meal to remove antinutritional factors have been developed. These include enzyme treatment, fermentation, and the removal of soluble carbohydrates.

Like soybean meal, rapeseed products are usually not fed to weanling pigs due to the presence of glucosinolates and relatively high concentrations of fiber in these products. Previous research has shown that fermentation of soybean meal can reduce antinutritional factors and fiber concentrations. An experiment was conducted to determine the apparent total tract digestibility (ATTD) of energy and concentrations of digestible (DE) and metabolizable (ME) energy in four sources of processed soybean products, conventional soybean meal, conventional 00-rapeseed expellers, and in a fermented mixture of co-products including 00-rapeseed expellers, wheat bran, potato peel, and soy molasses.