BRD-Causing Bacteria: What You Should Know

Understanding the causes of Bovine Respiratory Disease (BRD) can help producers protect their animals and prevent the disease, saving time, money and stress. BRD can be caused by bacteria that combine and move into the lungs, resulting in pneumonia. The three most common types of BRD-causing bacteria are Pasteurella multocida, Mannheimia haemolytica and Histophilus somni.

The results of new research shows that these bacteria found in cattle can become predominant or combine in different ways to lead to pneumonia and BRD when left untreated. P. multocida is most commonly associated with pneumonia in young beef or dairy calves but also is becoming more common in weaned cattle.

P. multocida and M. haemolytica are leading bacterial pathogens responsible for pneumonia in cattle. Though they are not always disease causing when present in cattle, P. multocida and M. haemolytica can be dangerous when not managed properly. This can happen when animals become stressed.

 “Pasteurella multocida is a commensal organism – that is, it exists without causing apparent harm – commonly found in the upper respiratory tract of cattle,” says Lowell Midla, D.M.V. with Merck Animal Health. “The problem arises when Pasteurella multocida winds up in the lower respiratory tract and lungs, most commonly secondary to viral disease or other insults that compromise the animal.”

P. multocida has been found to be more prevalent in cattle than it has in previous years. This could be due to antimicrobial resistance that alters bacterial populations over time.  At a U.S. university, bacterial culture results from submissions involving BRD yielded M. haemolytica from 22.3 percent of cultures, but P. multocida was not far behind, with presence in 21.6 percent. 1 In recent data from another U.S. university, P. multocida was found in 17 percent of the cultures and M. haemolytica was found in 14.6 percent.1 

Pasteurella multocida is a pathogenic bacterium that has always been associated with BRD in cattle, but seemingly hasn’t been discussed as a priority until recently,” says Dr. Midla. “This research confirms the importance of working with your veterinarian to ensure you’re doing everything you can to protect your cattle against respiratory disease, including dual-bacterial pneumonia protection.”

Most respiratory vaccines on the market today don’t include P. multocida control.

“Having that double protection against both Pasteurella multocida and Mannheimia haemolytica is going to back you up, helping to fully cover cattle against BRD,” Dr. Midla says.

Once PMH® IN is the only intranasal vaccine that delivers dual-bacterial protection against Mannheimia haemolytica and Pasteurella multocida. It is adjuvant-free and safe for cattle as young as 1 week of age, so you can begin to build immunity from the start. Once PMH® SQ also provides dual-bacterial protection against Mannheimia haemolytica and Pasteurella multocida, and offers the longest proven duration of immunity (16 weeks) against both.
Vista® Once offers dual-bacterial protection against Mannheimia haemolytica and Pasteurella multocida, in combination with five-way, modified-live viral protection against BRSV, BVD (Type 1 and Type 2) and PI3, IBR.

  1. Data submitted from Merck Animal Health. *U.S. University 1 included 2,514 bovine respiratory cultures; U.S. University 2 study included 947 bovine respiratory cultures and 406 bovine respiratory mycoplasma cultures.