BRD in perspectiveThis week in Denver, veterinarians, researchers and producers are engaged in the 2014 BRD Symposium, focused on the theme of “New Approaches to Bovine Respiratory Disease Prevention, Management and Diagnosis.” Purdue University veterinarian Mark Hilton, DVM, ABVP, kicked off the program with an overview of the past, present and future of BRD control in cattle. 

Hilton, and others throughout the conference, pointed out that while the beef and dairy industries have battled BRD for years improved vaccines, treatments and management systems, the disease remains the number-one disease of stocker, backgrounder and feedlot cattle in North America. In feedlots in the United States, BRD accounts for 70 to 80 percent of all feedlot morbidity and 40 to 50 percent of all mortality. According to a 2011 feedlot study from the USDA’s National Animal Health Monitoring System (NAHMS), 16.2 percent of all feedlot cattle were treated for BRD.

In fact, Hilton says, we have a higher incidence of BRD in feedlots today than we had 20 years ago. According to NAHMS data,  from 1994, 1999 and 2011 shows BRD deaths increased from 10.3 per thousand head in 1994 to 14.2 per thousand head in 1999 and to 16, or 1.6 percent death loss by 2011.

The industry can do better, Hilton says, but there is no single, simple solution. Reducing BRD losses will require efforts across the production chain, with prevention measures beginning at the cow-calf stage.

Control of BRD is confounded by the multifactorial nature of the disease complex. Viral pathogens involved can include Infectious Bovine Rhinotracheitis (IBR), Bovine Viral Diarrhea (BVD), Parainfluenza 3 (PI3), and Bovine Respiratory Syncytial virus (BRSV), while bacteria include Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis.

In addition to the pathogens, risk factors for BRD include stresses associated with weaning, surgical procedures at or near weaning, lack of immunity, changes in diet, comingling of cattle, transportation, dust, parasitism, concurrent diseases, and weather extremes.

Numerous studies have shown preconditioning programs, including comprehensive vaccination and weaning on the farm of origin for at least 30 days, can dramatically reduce BRD morbidity and mortality in calves shipped to the next production stage. However, the benefits of a good preconditioning program are best achieved if the preconditioned calves ship to operations that exclusively, or near exclusively purchases calves of similar health backgrounds. Even the best preconditioned calves probably will have high rates of BRD losses when placed in a feedlot filled with unweaned, unvaccinated, high-risk calves, largely due to exposure to large populations of BRD pathogens.

So why are more stocker operations and feedlots stocked full of low-risk preconditioned calves? The answer involves perceptions and economics, Hilton says. Some cow-calf producers still see preconditioning as a cost, and have not recognized the potential economic returns generated by efficient weight gains and heavier market weights in addition to any market premiums for calves preconditioned and weaned for 30 to 45 days. On the buyers’ side, some cattle feeders continue to look for calves they perceive as a bargain. At times, they have made good profits by purchasing high-risk lots of calves, straightening them out the best they can and accepting a high disease incidence as a cost of doing business.   

Hilton believes some portion of the backgrounding and feeding sector will continue to take chances on cheaper, high-risk calves if they are available, so the focus should be on educating cow-calf producers on the benefits of early prevention and preconditioning. He suggests that instead of just discussing the buyer-dependent “preconditioning bonus,” veterinarians and the industry should highlight the profit from additional pounds sold and profit per hour for the cow-calf enterprise, which is seller-dependent.

Hilton provides the following lists of potential steps for reducing BRD, grouped by their likely impact on diseases incidence.  

Questionable Impact

  • Develop new BRD vaccines and/or bacterins to give at feedlot entry.
  • Develop new and longer-acting antibiotics.

Potential Impact

  • Increased study on micronutrients that are important for immune function.
  • Improve preweaning nutrition of calves.
  • Discover new viral or bacterial pathogens that cause BRD.
  • Develop new BRD vaccines and/or bacterins to be given well before entering marketing channels.
  • Discover genetic components of BRD susceptibility.

Likely Impact

  • Improve immunity of calf before it arrives at feedlot.
  • Increase age of cattle at feedlot entry.
  • Feed more calves to slaughter at farm of origin eliminating co-mingling.
  • Decrease number of high-risk calves entering marketing channels.
  • Perform all surgeries at farm of origin.
  • Demand by retailers for beef from preconditioned calves based on enhanced animal welfare.