Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the assessment of Calsporin^® (Bacillus velezensis DSM 15544) as a zootechnical additive for dairy cows and other dairy ruminants. The product under assessment is based on viable spores of Bacillus velezensis DSM 15544. B. velezensis is considered suitable for the qualified presumption of safety (QPS) approach to safety assessment. The identity of the active agent was established and compliance with the applicable qualifications confirmed. Therefore, B. velezensis DSM 15544 is presumed safe for the target species, consumers of products derived from animals fed the additive and the environment. Since no concerns are expected from the other components of the additive, Calsporin^® is also considered safe for the target species, consumers of products derived from animals fed the additive and the environment. The additive is not a dermal/eye irritant or a skin sensitiser but should be considered a respiratory sensitiser. The FEEDAP Panel is not in the position to conclude on the efficacy of Calsporin^® for dairy cows or other dairy ruminants based on the data provided.