A clinical trial of recombinant bovine interferon alpha 1 for the control of bovine respiratory disease in calves.

The effects of recombinant bovine interferon alpha 1 (rBoIFN alpha 1) on the incidence of bovine respiratory disease (BRD) were examined in 60 young male cattle. Each group of clinically healthy 30 male cattle was injected intramuscularly with either rBoIFN alpha 1 (5 mg/head) or physiological saline 5 times in 6 months. They were examined daily for the clinical symptoms of respiratory distress. The clinical signs of respiratory distress in rBoIFN alpha 1-treated cattle were significantly less severe than those of the placebo group. The incidence rate, relapse rate and mean sick days of respiratory disease in the rBoIFN alpha 1-treated group were 23%, 14% and 4.43 days, respectively, whereas those in the placebo group were 80%, 46% and 6.42 days, respectively. Furthermore, the mean increase of body weights in rBoIFN alpha 1-treated group and placebo group were 1.365 kg/day and 1.340 kg/day, respectively. These results suggest that rBoIFN alpha 1 has a potentially preventive effect on the incidence of BRD.