South Dakota State University Extension's online teaching platform, iGrow.org recently introduced a risk categorization strategy for cattle producers that is based upon the potential for sickness and death in feeder calves and addresses Bovine Respiratory Disease (BRD).
A link to an article on this categorization strategy can be found at igrow.org/livestock/beef/brd-risk-categorization-for-feeder-calves-part-1/.
"This tool addresses BRD which is the leading cause of morbidity and mortality through the first 30 days following arrival to feeding programs," said Roger Ellis, SDSU Extension Beef Feedlot Field Specialist. "As widely documented in research and field reports, the calves which meet the criteria of "high-risk" experience increased disease incidence, costs and profit losses; by assigning a BRD risk level allows cattle feeders to manage calf health according to the degree of risk."
Ellis says many cattle producers ask what levels of BRD are commonly expected with "high-risk" feeder calves? He says reported incidence rates for calves treated for BRD regularly exceed 15 percent and often are greater than 50 percent.
"Death losses greater than 2 percent and case fatality rates greater than 20 percent are commonly experienced. Chronic BRD cases (non-responders to treatment) may exceed 25 percent. BRD at these reported levels has devastating economic and emotional effects on stocker and feeder operators," he said. "The challenge remains to understand these risks and implement sound health management programs to minimize the losses."
Many contributing factors have been identified which increase the risk for BRD in weanling calves. Ellis says within the established marketing avenues, calves are exposed to environmental and management stressors and challenged by infectious agents that are associated with BRD.
Factors associated with BRD in calves include (Acquired Factors)
- Weaning stress
- Handling and transportation stress
- Movement through cattle markets or congregating facilities
- Commingling of calves from multiple origins
- Delays in direct movement to the feeding operation ("holding")
- Excess shrink (body weight loss) during transit
- Weather stressors
Conditions as nursing calves associated with BRD include (Pre-existing Factors)
- Immunological deficiencies (insufficient colostrum-derived immunity)
- Previous disease (nursing calf health problems)
- Presence of PI (persistently infected) BVD calves
- Lack of or insufficient pre-marketing vaccinations for BRD agents
- Failure to castrate bull calves and dehorn nursing calves
- Nutritional deficits or imbalances
Designating newly received feeder calves as "high-risk" should heighten the level of management upon arrival.
"Cattle that have shrunk more than 7 percent can be assumed to be highly stressed and at high risk for health problems," he said.