Developing point of decision diagnostics for bovine respiratory disease

Development of an in-feedlot diagnostic test for accurate and timely identification of pathogens associated with bovine respiratory disease complex (BRDC) presents specific challenges due to the necessary logistics of feedlot practice and animals management. Staff ratios associated with intensive beef production, coupled with the requirement for minimum interventions, means than a point-of-decision diagnostic must be accurate, fast, cost-effective and reliable to be useful and effective for improving animal outcomes as well as making a meaningful impact on economic margins at induction. Necessary minimisation of pulls for intervention and / or treatment equally presents a challenge for diagnosis and management of BRDC-affected animals in the hospital system, who rarely undergo detailed diagnostic workup. Development of an effective strategy for in-feedlot analysis of the major bacterial pathogens associated with bovine respiratory disease complex requires careful balance between cost of diagnostic test, reliability of results and time to reporting. This timeline must fit within existing feedlot workflows to be effective and useful for industry. A co-design approach was undertaken to develop an in-feedlot diagnostic tool capable of informing BRDC management decisions will be discussed. The importance of accurate quantification for PCR-based diagnostics will also highlighted by analysis of induction and hospital pen cattle from two commercial feedlots in Australia.