Economic impacts of Bovine Respiratory Disease and alternative measures for diagnosis in Australian feedlot cattle

Summary

Claudia Blakebrough-Hall applied for and was awarded an MLA Top-up Postgraduate Scholarship commencing in 2017, to support her while she undertook a PhD at the University of Sydney.

The thesis, titled ‘Economic impacts of Bovine Respiratory Disease and alternative measures for diagnosis in Australian feedlot cattle’, involved work undertaken at a commercial feedlot and processing plant and quantified the economic impact of clinical and subclinical Bovine Respiratory Disease (BRD). The study also examined alternative mechanisms for diagnosis of BRD in feedlot cattle.

The studies demonstrated that there are large production and economic losses associated with increasing BRD severity. To reduce the effects of severe BRD, indicators of severity and mortality identified in the thesis (such as visual signs, ADG to first BRD pull, the number of BRD treatments an animal receives, lesions of the respiratory tract and naivety to certain BRD viruses) can be used to identify at-risk animals earlier and allow for more targeted treatment protocols.

Objectives

The objective of this MLA project was to provide support to PhD scholars to work in areas of relevance to the red meat industry and ensure the availability of scientists to deliver RD&A outcomes to industry. 

Key findings

The thesis assessed the economic impacts of BRD in feedlots and explored the use of alternative measures for BRD diagnosis. It identified:

• animals that were treated more than once for BRD had large reductions in performance, slaughter value and net returns
• subclinical BRD reduced average daily gain (ADG), slaughter value and net returns compared to animals not affected by BRD
• timely and accurate detection of animals with subclinical BRD could improve profitability by up to $67 per affected animal, leading to $5.60 lost profit for every animal inducted
• detection of BRD based on visual signs is an important tool to control BRD, and shows more merit as an indicator of BRD than most of the other common diagnosis measures, which highlights the importance of pen riders that are sufficiently trained to identify early signs of BRD.
• blood metabolomics has potential as an alternative diagnosis tool for BRD in feedlots, though further development is required.

Benefits to industry

The project made a significant contribution to BRD research and knowledge by:

• quantifying the detrimental economic effects of BRD in Australian feedlots
• establishing the effects of subclinical BRD on animal performance and economic returns
• identifying potential new methods of BRD detection worthy of further investigation.

Industry now has access to an early career scientist who is familiar with industry practices.

MLA action

MLA will make the results of the thesis work available to industry and the consulting veterinarians working in the feedlot sector through the biannual veterinarians and nutritionist consultation meetings.

Future research

Further research to examine the potential of blood metabolomics as a BRD diagnostic is warranted and will be considered for future funding. Initially, work will involve using independent datasets from multiple feedlot sites to determine the repeatability of the results and ensure the consistency of metabolite biomarkers across different cohorts of animals.