Lockout is a sterile, non‑antibiotic teat sealant for non‑lactating dairy cattle designed to aid in the prevention of new intramammary infections. Each 4 g syringe contains a smooth, blue paste with 60% bismuth subnitrate in a mineral oil vehicle that forms a malleable barrier in the teat canal. This physical barrier helps reduce bacteria entering the teat canal, supporting a lower incidence of mastitis as part of a comprehensive herd mastitis control program. Ideal for dry cow management, this livestock health product is intramammary, easy to use, and comes in a convenient 144‑syringe pail.