Whole crop barley was harvested (about 35% DM), chopped and then ensiled used laboratory scale silos (3.25±0.25 kg). The forage was ensiled as Untreated (UT) or treated using the following additives; fonnic acid (3.4 or 6.8 mL kg-DM; F3 or F6, respectively) acetic acid (3 or 4 mL kg- DM; A3 or A4, respectively) propionic acid (3 or 6 g kg-ofDM; P3 or P6, respectively) ammonium propionate (0.75, 1 or 1.5 g kg-ofDM; API 0.75 or AP1.5, respectively) Lactabacillus plantarum (8 xlOl 0 CFU (LP8) or l6xl 01 0 CFU (LP16) per g of DM) or mixed with Pediococcus pentosaceus plus Propionbacter freudenreichii (5.5 xl 01 0 CFU (PP5.5) or 11 xlOl 0 CFU CPPll) per g ofDM). Four replicates were performed for each treatment. Chemical composition, silage extracts pH and NH3-N and in situ nnninal degradation parameters ofDM, CP and NDF were determined. The additives caused a significant difference in the silage regarding chemical composition. Short chain organic acids did not have a significant effect on NH3-N and CP but acetic acid decreased pH of the silages (p<0.05). Biological inoculants resulted to decrease pH and LP8 decreased significantly NH3-N (LP8:7 .77 vs. lllltreated: 9.10 mg dL -1). Adding the buffered propionic acid based additives decrease pH and increase concentration of ammonia-N in the silage. Data of dry matter degradable coefficients showed that the slowly degradable fraction of the silage was affected by the treatments. Degradable coefficients ofNDF of the silages were affected by the additives used (p<0.05). The addition both quickly and slowly degradable coefficient of CP were influenced by the treatments used (p<0.05).

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