Acetylisovaleryltylosin tartrate, commonly known as tilmicosin, is a macrolide antibiotic used in veterinary medicine primarily for the treatment of respiratory bacterial infections in cattle and swine. It is effective against key pathogens such as Mycoplasma bovis, Pasteurella multocida, Actinobacillus pleuropneumoniae, and Histophilus somni, making it a standard treatment for bovine respiratory disease complex (BRDC) and swine respiratory disease. The compound provides long-acting activity, often administered via injection for cattle or incorporated into feed for swine, which reduces dosing frequency. Note: It is not approved for use in poultry, and while related tylosin derivatives may serve as growth promoters, tilmicosin is primarily therapeutic rather than for growth promotion.