Many different risk factors combine to cause bovine respiratory disease (BRD) in feedlot cattle. A group of researchers at the University of Queensland in Australia recently published a series of papers that investigated how different management options impacted the risk of cattle being diagnosed with BRD within the first 50 days after feedlot arrival. Although there are some differences between the cattle industries in Australia compared to North America, both continents experience many similar BRD risk factors. These researchers found that the greatest risk of BRD occurred in cattle that had not been mixed with cattle from other herds until the 12 days leading up to the time they entered the feedlot and then were mixed with cattle from four or more herds. Cattle that had not been exposed to cattle from other herds until they arrived at the feedlot also had increased risk compared to cattle with the lowest risk – those that had been mixed with cattle from a few (less than 4) other herds more than 27 days before they were shipped to a feedlot. Cattle that were shipped to the vicinity of the feedlot and placed on pasture at least 27 days prior to feedlot entry had reduced BRD risk than cattle shipped even short distances (
Reducing the risk of BRD in feedlot cattle requires that cow-calf producers and feedlot operators use multiple management interventions including vaccination well-before shipment, appropriate weaning strategies, and controlling the timing of mixing of cattle from multiple herds prior to feedlot entry.
Risk factors for bovine respiratory disease in Australian feedlot cattle: Use of a causal diagram-informed approach to estimate effects of animal mixing and movements before feedlot entry. Preventive Veterinary Medicine 117:160-169, 2014. K.E. Hay, T.S. Barnes, J.M. Morton, A.C.A. Clements, T.J. Mahony. Link to article
Effects of exposure to Bovine viral diarrhea virus 1 on risk of bovine respiratory disease in Australian feedlot cattle. Preventive Veterinary Medicine 126:159-169133, 2016. K.E. Hay, R.C.K. Ambrose, J.M. Morton, P.F. Horwood, J.L. Gravel, S. Waldron, M.A. Commins, E.V. Fowler, A.C.A. Clements, T.S. Barnes, T.J. Mahony. Link to article
Associations between prior management of cattle and risk of bovine respiratory disease in feedlot cattle. Preventive Veterinary Medicine 127:37-43, 2016. K.E. Hay, J.M. Morton, M.L. Schibrowski, A.C.A. Clements, T.J. Mahony, T.S. Barnes. Link to article
Associations between exposure to viruses and bovine respiratory disease in Australian feedlot cattle. Preventive Veterinary Medicine 127:121-133, 2016. K.E. Hay, T.S. Barnes, J.M. Morton, J.L. Gravel, M.A. Commins, P.F. Horwood, R.C. Ambrose, A.C.A. Clements, T.J. Mahony. Link to article