BRD can be costly
Published on Jan. 25, 2020“Producers mostly associate Bovine Respiratory Disease (BRD) with cattle under a lot of stress in the feed yard,” states Kansas State University (KSU’s) Veterinarian Hans Coetzee during KSU’s Agriculture Today podcast, published Jan. 21. “However, BRD is actually a year-long issue.”
According to the Beef Cattle Research Council (BCRC), BRD is the most common and costly disease effecting cattle in the U.S.
Coetzee notes BRD is commonly associated with infection of the lungs, which ultimately causes pneumonia and in severe cases, death.
Traditionally, in cases of BRD, producers deploy antibiotic treatments, according to Coetzee.
“Antibiotics are really the basis of prevention and treatment of BRD in a lot of production systems,” he says. “There are vaccines available for trying to protect animals from developing the disease but more often, antibiotics are used on newly arrived or high-risk cattle to prevent them from getting infected.”
Coetzee notes all antibiotics can be categorized into two groups.
“These two groups are the antibiotics that kill the bacteria causing the infection, and we call those bactericidal antibiotics,” he explains. “Then there are the antibiotics that prevent the bacteria from dividing and multiplying in the animal, and these antibiotics require the animal to have an active immune response against the bacteria and actually eliminate the infection.”
Coetzee further explains he and his colleagues at KSU were interested in looking at these two classes of antibiotics and trying to understand if there was an interaction between them and antibiotic resistance when treating BRD.
“There is certainly a trend at this time for those in the cattle industry to want to understand the impact of using antibiotics on their animals and the emergence of bacteria that are no longer susceptible to the antibiotics,” Coetzee states.
He explains the KSU study looked at samples of infected, deceased animals that were sent to the Iowa State University Diagnostic Laboratory.
“We looked specifically at the association of the treatments producers had used under the direction of their veterinarians and the outcome in terms of whether we isolated resistant bacteria from those animals or not,” he says.
“We had 780 samples which gave us a very broad set of data and allowed us to look at some specific relationships between which drugs were used to treat the animals and the probability of isolating bacteria that was no longer susceptible to the antibiotic,” Coetzee adds.
Rethinking BRD treatment
According to Coetzee, the results of the KSU study found more isolated bacteria resistant to multiple antibiotics in situations where producers began by treating a BRD-infected animal with an antibiotic that prevents bacteria from dividing then switched to a bactericidal antibiotic when the initial treatment was unsuccessful.
“In the past we advised and recommended producers switch antibiotic classification when initial treatment was unsuccessful,” Coetzee explains. “We are very concerned this may actually be enhancing the resistance in the bacteria causing BRD and may be a risk factor for resistance development.”
Therefore, Coetzee urges producers to rethink their BRD treatment strategies.
“We are not suggesting using the same drug for the second treatment, but now we suggest staying in the same broad class of antibiotic,” he notes. Hannah Bugas is the assistant editor for the Wyoming Livestock Roundup. Send comments on this article to firstname.lastname@example.org.