Managing BRD in High-Risk Calves: What the Latest Data Tells Us

By Dr. Jacques Fuselier, DVM, MVS, DACT, DABVP, Merck Animal Health Cattle Technical Services Veterinarian

Bovine Respiratory Disease (BRD) poses a significant threat to cow-calf operations and continues to be the most economically damaging illness in feedlot settings.¹ While we’ve made strides in prevention, treatment remains essential for keeping cattle healthy and on track. As a veterinarian, I’ve seen firsthand how early, effective intervention can mean the difference between recovery and a chronic case. With cattle prices at a premium, managing health-related risk is more critical than ever to protect your investment.

Choosing the right treatment option is an ongoing topic of conversation among veterinarians and producers. The animal’s biological processes, combined often with different bacteria and viruses at play, plus environmental and management stressors, add to the complexity. BRD isolates also have shown resistance to antibiotics frequently used. These factors can make the decision on what antibiotics to use in certain situations less clear-cut and more subjective than we would like.

Tracking the right metrics can help determine antibiotic selection and protocol adjustments. It’s important to note the class and weight of cattle as those factors will impact clinical outcomes.

Level set your goals based on incoming risk level and treatment history

You will want to establish realistic goals based on the risk level of cattle being received. No vaccine or antibiotic on the market will move high-risk cattle into low-risk health numbers. Work with your veterinarian to determine the BRD-related health metrics to track. This could include BRD pulls per day, daily mortality and causes, pen mortality and more.

Next, work with your veterinarian to determine processing and treatment protocols. When it comes to first treatment for BRD, consider if the animal has been given an antibiotic previously, and if yes, what class of antibiotic. Anecdotally, with the increase in options and lower prices of tulathromycin, it is anticipated that tulathromycin will be used heavily for metaphylactic antimicrobial therapy. For first treatment antibiotic selection in these animals, studies show the use of florfenicol significantly reduces mortality.²

Study compares treatment success, financial impact

A recent study compared treatment success of steers treated for BRD with either RESFLOR GOLD® (florfenicol and flunixin meglumine) or Norfenicol® (florfenicol).2 The objective of this study was to compare treatment success of calves treated for BRD with either RESFLOR GOLD or Norfenicol when tulathromycin was used at feedlot arrival as a metaphylactic antibiotic.

Cattle in this study population treated for BRD using RESFLOR GOLD had 40% less death loss than those given Norfenicol. Cattle receiving Norfenicol treatment were 2.1 times more likely to die from BRD and were 1.7 times more likely to die from all causes than cattle receiving RESFLOR GOLD. See Table 1.

Table 1

Through the 120-day duration of this study, overall mortality was significantly lower for steers treated with RESFLOR GOLD (5.6%) than for steers treated with Norfenicol (9.6%). BRD mortality was significantly lower for steers treated with RESFLOR GOLD (2.8%) than for steers treated with Norfenicol (6.0%).

Comparing the cost difference between RESFLOR GOLD and Norfenicol, there was a $7.80 savings when using Norfenicol. However, with RESFLOR GOLD, there was a $43 per head advantage in BRD death loss [(486 lb./head x $2.95/lb. purchase price x 3 head)/100]. In the end, there was a $35 advantage per treated calf with RESFLOR GOLD.

When BRD hits, timing and treatment matter

Mortality represents an objective economic loss. Results from this study identified a significant difference between treatments with respect to overall and BRD pneumonia mortality. When you’re investing in high-dollar calves, the right treatment given at the right time results in more cattle making it to the rail.

References

Griffin, D. Economic impact associated with respiratory disease in beef cattle. Vet. Clin. North Am. Food Anim. Pract. 1997. 13(3):367-377. Doi:10.1016/s0749-0720(15)30302-9
Data on file. Merck Animal Health Tech Bulletin (US-REF-240800001).
Merck Animal Health. Comparison of RESFLOR GOLD® to Norfenicol for Treatment of Bovine Respiratory Disease in Holstein Steers Following Metaphylaxis with Tulathromycin. Final Study Report. 2025. MS-Resflor-Gold-01-25.

IMPORTANT SAFETY INFORMATION FOR ESTRUMATE

RESFLOR GOLD® is not for use in humans. Keep out of reach of children. Do not use in animals that have shown hypersensitivity to florfenicol or flunixin. Avoid direct contact with skin, eyes and clothing as product contains materials that can be irritating. Animals intended for human consumption must not be slaughtered within 38 days of treatment. This product is not approved for use in female dairy cattle 20 months of age or older, including dry dairy cows. Use in these cattle may cause drug residues in milk and/or in calves born to these cows. A withdrawal period has not been established in preruminating calves. Do not use in calves to be processed for veal. Not for use in animals intended for breeding purposes. For complete safety information, refer to the product label.