p.p.s. I forgot to mention that Tylosin is used in cattle at a SUB-THERAPUTIC dose...ie. it is not used for ACTIVE infections, rather it is used to prevent infections from occurring in the first place by giving it to cattle on a consistant basis. If a cow does come down with an active infection, only antibiotics obtained from a vet are used (Baytril, etc.) (which should tell you something about the power of Tylosin to treat an active infection...in other words, it doesn't).