Soya beans are rich in protein with a valuable composition of amino acids but also contain anti-nutritive substances (trypsin inhibitors) and approximately 20 % fat, which can limit the applicability in organic pig husbandry.
If soya beans are pressed and heat treated, the products can be used in organic feed rations for pigs. Critical points in ration planning must be considered to achieve a high meat quality.
• Soya beans need to be heat treated to enable digestion by pigs or poultry. Professional processing technology is required to apply a heat treatment of the right quality and intensity. This is essential to preserve protein quality.
• De-fatting of soya beans helps to increase shelf life and the amount that can be fed to sows, piglets and pigs. A mechanical press reduces the fat content down to approximately 7-10 %, see table 1. The product is called soya cake (see figure 1). Before feeding it to pigs, it needs to be heat treated.
• Soya cake or full-fat soya beans are best in growth phases with high energy needs: nursing sows, rearing piglets and in the first fattening phase (share in total feed <15 % DM), see table 2.
• The fat of soya beans contains relatively high levels of polyene fatty acids. For achieving lean meat of high quality, the use of soya cake is limited during the final fattening phase (approximately 5 % of DM). Full-fat soybeans should be avoided during this phase.
• If soya cake is the main protein feed during the fattening period, the share of corn should be lower than 20 %. Otherwise, lean meat of high quality is not achievable.