Increasing selenium concentration in Finnish organic milk using participatory action approach

Selenium (Se) is an essential trace element for animals. In Finland, Se supplementary feeding and Se-enriched macronutrient fertilisers are used in conventional farming because the Se availability from soil is extremely low. The objective of this study was to improve Se concentration in organic milk by replacing sodium selenite (SS) in mineral-vitamin mixture with selenium yeast (SY) either completely or partly (50/50). The feeding experiment was conducted on 15 certified organic dairy farms in Eastern Finland during spring 2008. The cross-over design consisted of three treatments (SS treatment, SY treatment, and SS/SY treatment), three experimental periods (28 days each), and three farm groups (different order of treatments). Replacing SS with the same amount (0.2 mg Se kg-1 feed dry matter) of SY more than doubled Se concentration in organic milk and their mixture resulted in slightly lower Se concentrations. In conclusion, SY supplementary feeding is needed to improve Se concentration in organic milk and Se supply to cows, their calves, and consumers.