BOXMEER (Netherlands), – In a Canadian field trial in feedlot cattle recently published in Veterinary Therapeutics, it was demonstrated that treatment of undifferentiated fever related to Bovine Respiratory Disease (BRD) with RESFLOR® (florfenicol plus flunixin meglumine) was associated with a lower mortality, resulting in higher economic benefit as compared to treatment with tulathromycin or ceftiofur.

The main finding of this blinded research study was a statistically significantly decreased overall mortality rate in the RESFLOR group (2 percent) as compared to animals treated with tulathromycin (10 percent) or ceftiofur (20 percent), despite a higher initial fever relapse rate with RESFLOR (14 percent) as compared to tulathromycin (4 percent). The lower overall mortality rate resulted in a statistically significant net economic advantage for RESFLOR of Can$ 46 per treated animal versus tulathromycin and Can$ 108 per treated animal versus ceftiofur. There were no marked differences between the three groups with respect to other morbidity factors, cause-specific mortality rates, feedlot performance, carcass grading or slaughter lung scoring data.

The study was funded by Intervet/Schering-Plough Animal Health and recently published by Dr. Sherry Hannon and colleagues in Veterinary Therapeutics*. The study was performed in 150 beef steer calves, who had received long-acting oxytetracycline on arrival and were vaccinated against infectious bovine rhinotracheitis virus, parainfluenza-3, bovine viral diarrhea virus and bovine respiratory syncytial virus at an average of 63 days after enrollment. Only animals presenting with undifferentiated fever (rectal temperature >40.5°C/105.0°F) and presence of subjective clinical signs of illness indicative for BRD (depression, lethargy, nasal discharge, cough, absence of abnormal clinical signs related to other organ systems than the respiratory system) were included in the trial. The animals were randomized to a single injection with standard doses of either RESFLOR (florfenicol plus flunixin meglumine), tulathromycin or ceftiofur and were monitored until slaughter.

Undifferentiated fever is a clinical syndrome that is also often referred to as Bovine Respiratory
Disease (BRD) or “shipping fever” (as it is often diagnosed in recently transported cattle trying to
cope with the stress of a new environment). It is one of the most common animal health
concerns in calves entering feedlots. Although the specific approach may vary depending on the
predicted risk for development of the syndrome, it typically includes a combination of
vaccination, responsible treatment and animal management at or soon after feedlot arrival.

Hannon SJ, Perrett T, Wildman BK, Schunicht OC, Vogstad AR, Fenton RK, Burciaga-Robles LO, Pollock CM, Jim GK, Berg J, Booker CW. Efficacy of a florfenicol-flunixin meglumine combination product versus tulathromycin or ceftiofur crystalline free acid for the treatment of undifferentiated fever in feedlot cattle. Veterinary Therapeutics 2009;10:E1-E18