A sterile, ready-to-use injectable antimicrobial solution that contains enrofloxacin, a broad-spectrum fluoroquinolone antimicrobial agent indicated for the effective treatment and control of respiratory disease. Can be used in beef cattle, non-lactating dairy cattle, and swine. Treats and controls bovine respiratory disease (BRD) and swine respiratory disease (SRD). Also for control of colibacillosis in swine. Cattle: convenient single-dose and multi-day therapy. Swine: administer intramuscular or subcutaneous. Each mL of Quellaxcin™ 100 contains 100 mg of enrofloxacin. Not for use in female dairy cattle 20 months of age or older or in calves to be processed for veal.