Minimising the BRD impact in feedlots: Progress in three key R&D projects

Beef Central, 20/05/2022

A SERIES of industry-backed research projects is looking at preventative measures for minimising the impact of bovine respiratory disease in feedlot environments.

Under work being carried out through MLA and partners, an upcoming trial into autogenous vaccines will investigate potential vaccines for some of the bacterial pathogens involved in BRD, impacts from which are estimated to cost the Australian beef industry around $50 million each year.

Emerging diagnostic technologies and an updated handbook for industry are providing tools to prevent and better manage BRD in feedlots across Australia.

MLA’s feedlot program has a large R&D focus on preventative, diagnostic and extension measures for minimising the impact of BRD.

These measures include development of new vaccines, improving diagnostic technologies, and updating the Bovine Respiratory Disease Preventative Practices handbook for industry.

MLA’s project manager for feedlot & sustainability, Dr Matt Van der Saag, said the aim of the projects was to improve and maximise the health, welfare and productivity of grainfed cattle, which in turn will increase enterprise profitability.

Here’s a summary of recent project work:

Autogenous vaccine evaluation

Autogenous vaccines are custom vaccines produced from bacteria isolated from animals at the source feedlot to stimulate immunity against those strains included in the vaccine.

Commercial vaccines currently available in Australia offer protection against Bovine herpesvirus, Bovine pestivirus and Mannheimia haemolytica, whereas the BRD complex involves additional bacterial pathogens that are not targeted by readily available vaccines.

MLA has joined forces with the University of Adelaide’s associate Professor Kiro Petrovski and Apiam Animal Health’s Dr Tony Batterham, to evaluate if autogenous vaccines approved by the Australian Pesticides and Veterinary Medicines Authority confer additional protection from BRD, leading to improved health and welfare, reduced antimicrobial treatments and increased profitability.

The project, which starts this year and conclude in December 2024, will deliver three large scale randomised block-controlled studies investigating one or two shot autogenous vaccine protocol for combined P. multocida and H. somni and a M. bovis autogenous vaccine.

“We are currently working with MLA and Apiam Animal Health to determine which sites this trial will commence, as well as identifying the vaccine strain candidates. This will be followed by regular surveillance and testing of those specimens thereafter for the duration of the project,” Prof Petrovski said.

Based out of Quirindi in north-west NSW, Dr Batterham noted that the upcoming study promises exciting news for beef feedlot operators and possibly other beef producers who can utilise the technology.

“This project seeks to provide an additional preventative control measure for BRD in beef feedlots, utilising autogenous vaccines approved by the APVMA,” he said.

“In this way, livestock teams working in beef feedlots can readily access these additional tools to mitigate BRD’s impact to the Australian beef sector. The vaccines are tailor-made to each feedlot site which provides source material. However, they require ongoing surveillance of the bacterial pathogens operating,” he said.

“This does align with good antimicrobial stewardship practices, delivering a win-win to operators and customers. These are positive developments for the beef industry.”

Emerging diagnostic technologies

Alongside vaccines, diagnostic technologies are an essential way to minimise and prevent BRD in feedlot cattle.

An ongoing project between MLA and Charles Sturt University through the Gulbali Institute of Agriculture, Water and Environment, in collaboration with NSW DPI is looking to quantify the cost of disease in feedlots including losses associated with carcases condemned with BRD.

Charles Sturt Professor Jane Quinn said the project used quantitative real-time polymerase chain reaction (qPCR)-based diagnostic methods to identify a range of pathogens related to BRD, within the same day, allowing this to be used for whole-mob decision making.

“Through our tests so far, we have found that these diagnostic tests show a quantitative concentration of potential pathogens in an animal,” she said.

“The reason this is important, is because this can show which animals are at risk of BRD before they get it.”

The technology development, led by Dr Ian Marsh at the Elizabeth Macarthur Agricultural Institute, is in the final stages of testing. The project is now undertaking an economic analysis and intervention modelling to understand how the tests can be practically incorporated into a commercial feedlot.

Bovine Respiratory Disease Preventative Practices handbook

Work is also progressing in providing easily accessible information for Australian feedlots and processors around BRD.

In 2016, MLA published the Evaluation of practices used to reduce the incidence of bovine respiratory disease in Australian feedlots. In 2021, MLA worked with Dr Paul Cusack at Australian Livestock Production Services to develop an updated handbook for the industry.

The updated handbook will contain new information relating to environmental, animal and management factors that affect the incidence of BRD in lotfed cattle published between 2016–2021.

“It provides a single source for lot feeders and their consultant veterinarians to access the latest information on BRD and how to prevent it,” Dr Cusack said.

Since the initial document was written, new developments in peer reviewed literature and industry best practice have emerged. The group wanted to make sure that these important developments were captured in the updated version.

“Although the information is deeply technical, it can really prove to be the world of difference to a lotfeeder, their cattle and their business,” Dr Cusack said.

The new updated handbook is available on the MLA website. Click here to access


Source: MLA





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