This poster, presented at the XXth ISFC 2026 (Lednice), summarizes semi-operational trial results of the CitroFor stabilizer (citric and formic acid, 95:5) in TMR for dry, lactating, and freshly calved dairy cows. In TMR for dry cows at 30 oC, the 4 l/t dose significantly reduced the temperature rise by 38% and completely eliminated mould and yeast growth (ANOVA, p = 0.033). The effect was insufficient in more energy-dense rations, and the 2 l/t dose was even counterproductive in post-calving TMR. Dosage recommendations are given by TMR type and ambient temperature.