Q & A on Treating Cattle for Bovine Respiratory Disease

Q & A on Treating Cattle for Bovine Respiratory Disease (BRD)

In this easy-to-read paper, you’ll learn about the common causes of BRD and how they relate to various disease situations, the economics of those situations, a disease concept known as "smoldering pneumonia", and what you can do to stay ahead of BRD.

Q. Which three bacteria are the most common causes of BRD?

A. Mannheimia (Pasteurella) haemolytica
Pasteurella multocida
Haemophilus somnus

Q. How do you know which one is causing the disease in the calves you’re treating today?

A. Can’t know for sure. Virtually 100 percent of BRD cases are multi-organism infections, with more bacteria invading as the disease advances.a

Q. What can happen if you don’t kill all the bacteria involved?

A. Costly repulls and chronics, and – most costly – death loss later in the feeding period.

Q. So, what bacteria should you treat for?

A. All three common causes of BRD. Start early and use a broad-spectrum antibiotic.

Probable Causes of Bovine Respiratory Disease Situations

Acute Cases

  • M. haemolytica: Incidence Index = 100b
    Causes sudden and severe disease.
  • Pasteurella multocida: Incidence Index = 80b
    Frequently accompanies M. haemolytica.


  • Animal not completely cleared of bacteria during first treatment.
  • Reinfection possible in animals with compromised immune systems.


  • Animal not completely cleared of bacteria during earlier treatments.
  • On-going infection with resistant population of bacteria possible.

Death Loss After 30 Days on Feed

  • Smoldering pneumonia caused by P. multocida.
  • Low-level, smoldering infection by Haemophilus somnus.

"Pasteurella multocida is commonly associated with chronic BRD that is described as smoldering – a low-level infection that doesn’t make calves sick enough to be pulled. Affected animals continue eating and possibly gaining weight, while the infection continues to spread and cause extensive lung damage.

Often, such an infection does not become apparent until the animal breaks back with a more acute M. haemolytica infection. Or the infection may smolder long enough to involve a large percent of the lung before it becomes clinical. Often, clinical detection is too late in the disease process for treatment to be effective. Widespread mortality results." c

Economics of Bovine Respiratory Disease: Where the Dollars Go

Disease Situation Primary Economic Considerations
Acute cases Treatment cost and labor
Repulls Treatment cost and labor
Retreatment cost and labor
Performance loss
Chronics Treatment cost and labor
Retreatment cost and labor
Retreatment cost and labor
Performance loss
Carcass value loss
Death loss after
30 days on feed
Treatment cost and labor
Performance loss
Carcass value loss
Purchase price expense
Yardage expense
Feed expense
Customer dissatisfaction*
*A concern of custom feeders

Veterinarians and cattle feeders agree that approximately 66 percent to 75 percent of death loss occurs after 30 days on feed.d

What You Can Do to Help Stay Ahead of Bovine Respiratory Disease

  1. Treat affected animals early, particularly high-risk cattle, before extensive and irreversible lung damage occurs.

  2. Treat with a broad-spectrum antibiotic that is active against the 3 major bacteria – M. haemolytica, P. multocida, H. somnus – because you cannot know for certain what the causative ones are. Reducing the bacterial population will help limit repulls, chronics, and costly death loss.

    While M. haemolytica is believed responsible for most acute cases of BRD, Texas Veterinary Medical Diagnostic System recordsb show a high incidence of P. multocida infection also:

    Number of Isolates from Lung Tissue and Nasal Swabs, 1992-1998

      1992 1993 1994 1995 1996 1997 1998
    M. haemolytica 581 692 369 675 274 369 291
    P. multocida 476 480 361 432 239 317 273

    NUFLOR is effective against M. haemolytica, P. multocida, and H. somnus. It offers activity against the three bacteria most likely to be causing BRD.

  3. Treat with an antibiotic to which the most common BRD bacteria have shown a high degree of sensitivity.

    Antibiotic sensitivity datad reported by laboratories in Kansas, Nebraska, Oklahoma and Texas from 1995 through 1998 demonstrate bacteria’s high level of sensitivity to florfenicol:

    Sensitivity of Isolates to Florfenicol, 1995-1998

    State Laboratories Independent Laboratories
    Organism # Tested % Sensitive Organism # Tested % Sensitive
    M. haemolytica 923 99 M. haemolytica 586 99
    P. multocida 726 99 P. multocida 402 99
    H. somnus 184 99 H. somnus 66 99

    NUFLOR can help lower the costs of BRD. Its high level of activity against 3 major bacterial causes means animals can respond before a long-standing and expensive infection occurs.

  4. For best results, provide therapy for 4 days and observe animals daily for 5 days to fully assess treatment response.

    An ideal treatment regimen can be easily accomplished with NUFLOR: 4 days of therapy with one dose sub-Q or 2 doses IM 2 days apart.


a Mayer, John, DVM, Midlands Consulting, Omaha, NE. Observations on the complexity of bovine respiratory disease. Animal Health Forum, Fall 1995.

b Personal communication, Dr. Robert Sprowls.

c Sprowls, Robert, DVM, PhD and Post, Karen, DVM, MS, Texas A&M Veterinary Diagnostic Laboratory, Amarillo, TX. An examination of four bovine respiratory bacterial pathogens. Veterinary Scope, Volume 2, No. 2, 1992.

d Data on file, Merck Animal Health.