Abstract In 2013 the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) issued an opinion on the safety and efficacy of a strain of Lactobacillus brevis and four strains of Lactobacillus buchneri when used as feed additives for the production of silage. In those instances the Panel concluded that the strains were safe for target animals, consumers of animal products, users of the additive and the environment. However, owing to limited evidence of a beneficial effect on the ensiling process, the FEEDAP Panel was unable to draw conclusions on the efficacy of the L. brevis strain. The Commission has given the applicant the option of submitting additional information to allow the Panel reaching conclusions on the efficacy of this strain. The applicant has provided complementary information which is the subject of the current opinion. The results from the original submission and those newly submitted showed that the L. brevis strain has some potential to improve the production of silage from moderately difficult and difficult to ensile materials and to reduce the numbers of clostridia at the proposed application rate of 5 × 107 CFU/kg forage. No effect on aerobic stability was demonstrated.