Nuflor® vs Naxcel®: Clinical Trials Comparison

Bovine respiratory disease (BRD) is thought to be an interaction of several factors. It is often termed BRD complex, shipping fever, transit fever, fever of unknown origin, pasteurellosis, and Pasteurella pneumonia of calves. Regardless of the name applied, it is the most costly disease affecting cattle today.

It is believed that distressors including viruses, environment, nutrition, and management factors weaken body defenses, allowing the colonization of the lower airway with bacteria. The primary bacteria involved are Mannheimia (Pasteurella) haemolytica, Pasteurella multocida, and Haemophilus somnus. To achieve economical control of this disease, early treatment with an effective antibacterial is required. This study reports on the use of NUFLOR (florfenicol) Injectable Solution or Naxcel (ceftiofur) for treatment of naturally occurring BRD in feedlot situations.

NUFLOR is an injectable formulation of the broad-spectrum antibiotic florfenicol. Its unique formulation allows for the use of 2 intramuscular injections 48 hours apart or 1 subcutaneous injection for 96 hours of BRD therapy. Bronchial secretion levels exceed 3 µg/ml in less than 60 minutes and persist throughout the 4 days of therapy. MIC90 values for florfenicol are 1.0 µg/ml for M. haemolytica and 0.5 µg/ml for P. multocida and H. somnus.


The purpose of these trials was to determine the efficacy of NUFLOR (20 mg/kg IM repeated in 48 hours) or Naxcel (2.2 mg/kg IM SID x 3 days) against naturally occurring BRD in calves recently shipped into commercial feedlot environments. Animals were of southeastern U.S. origin and transported to 2 locations in the Texas panhandle during the late winter/early spring of 1995. There were approximately 200 head of 420-lb mixed breed beef cattle at each location, half treated with NUFLOR and half treated with Naxcel.

Allocation to treatment was by computer-based randomization. Criteria for entrance into the study included: pyrexia 104°F or greater, Clinical Index Score of 2 or greater, and at least one respiratory sign (respiratory rate >40, dyspnea, coughing, or nasal discharge). The studies were blinded by one person assigning calves and administering treatment while another performed the evaluations. The initial test drug could be readministered once if there were recurrent signs of BRD, up to 28 days after enrollment in the trial. Animals that died during the trials were necropsied and cause of death determined. Duration of the studies was 57 days.


Results are presented in Table 1. First Rx Success are those animals that received one complete course of therapy and required no additional therapy for BRD throughout the study period. Final Success are those animals that were treated once or twice with a full course of therapy and required no further therapy for BRD for the duration of the trial. Disease challenge was mild, and overall results of treatment were similar between the two antibiotics. There was a slight numerical, but not statistical, difference in favor of the group treated with NUFLOR. There were no adverse reactions to treatment reported in these trials.

NUFLOR is a registered trademark of Intervet Inc.

NAXCEL is a registered trademark of Pharmacia & Upjohn.