FINDING diagnostic tools to efficiently and objectively identify Bovine Respiratory Disease in feedlot cattle is the focus of a new research project that could potentially transform the industry.
The project, Metabolomics of Bovine Respiratory Disease, led by Associate Professor Luciano González from The University of Sydney, has three distinct objectives.
“There remains a huge challenge in trying to objectively identify sick animals in feedlots. The industry currently relies on visual observations of animals to detect Bovine Respiratory Disease (BRD) in the first instance, so it’s not an objective measure,” Prof González said.
Diagnosis for BRD in feedlots is based on visual and sound scoring of breathing difficulty, nasal and eye discharge and lethargy, with the use of rectal temperature above a defined level to trigger treatment protocols.
“What we want to do in this project is find new objective ways to identify sick animals,” Prof González said. “Further, we want to determine the true cost of the disease to the industry.”
Metabolomics diagnostic tool
The first goal of the project is to explore a possible BRD diagnostic tool known as metabolomics.
Metabolomics is a recent field of science that examines the metabolite profile of body tissues and fluids. The project will examine blood samples from both sick and healthy animals to look for informative biomarkers that could lead to the development of practical and cost-effective tests for BRD in feedlot cattle.
Blood tests will be done at two stages – at induction and then again at any time the animal is deemed to be sick by the pen riders and pulled out for inspection and treatment.
“For every sick animal removed from the pens, we’ll also pull out a healthy animal, so we can compare the blood results and body temperatures,” Prof González said.
The project’s second goal is to determine for the first time, the economic impact of BRD to Australian feedlots, using a retrospective analysis of BRD treatment records and lung abnormalities at slaughter accounting for treatment cost, loss of production, labour cost and opportunity cost, amongst others.
“We want to quantify every factor that may have a cost,” Prof González said.
The research is being undertaken at a commercial feedlot, with approximately 1760 animals set to be followed for 60 days from induction. The cattle will then be followed right through to the abattoir to measure lung scores for signs of adhesions and abscesses to see if there’s any evidence an animal has had an incidence of BRD.
“A lot of feedlot cattle go undetected for BRD, and it’s not until they arrive at the abattoir that we realise an animal has been sick, because lesions can be seen on their lungs,” he said.
“We will also be looking at carcase data to measure the impact of BRD on meat quality and yield.”
Prof González said the project’s third objective was to research a method of automatic detection of fever, using a technology known as infrared thermography, which can measure the temperature of objects from long distances.
Different versions of the technology will be trialled, from a small sensor that attaches to a mobile phone, through to a camera that can be set up in a race or pen.
“It allows us to measure body temperature without touching an animal, potentially improving animal management, reducing the use of antibiotics, and making treatments more effective,” Prof González said.
The BRD study is a grainfed levy project being managed by Meat & Livestock Australia in consultation with the Australian Lot Feeders Association.
MLA feedlot project manager, Dr Joe McMeniman, said with the adoption of antimicrobial stewardship guidelines by the feedlot industry, there will be an increasing requirement for accurate and objective case identification of BRD.
“We know that BRD is the leading cause of morbidity and mortality in Australian feedlot cattle. However, the true cost of diseases in feedlot cattle is largely unknown as there are hidden costs in managing sick animals such as feed consumption, time required for treatment and disposal where necessary,” Dr McMeniman said.
“Following animals in the study through to the abattoir will provide valuable insights. BRD results in lung damage of feedlot cattle with the signs commonly evident at slaughter.”
US feedlot research showed that cattle with lung abnormalities have decreased carcase weight and fatness, including marbling. Additionally, up to 50pc of cattle with lung abnormalities at slaughter exhibit no clinical signs of BRD during the feeding period. These undetected animals are termed ‘sub-clinical’.
No peer-reviewed data is available on the sub-clinical incidence of BRD of Australian feedlot cattle, Dr McMeniman said.
The new project would generate data to quantify the economic impact of BRD to Australian feedlots via an analysis of feedlot induction records, BRD treatment records and lung abnormalities at slaughter.
BRD vaccination now much more flexible
In other news this week regarding management of Bovine Respiratory Disease, animal health company Coopers has achieved a significant breakthrough in flexibility surrounding the use of its Bovilis MH+IBR vaccine.
In what promises to be a significant step forward for the further adoption of pre feedlot entry vaccination of feeder cattle, Coopers has been granted a label change, meaning the inter-vaccination interval (the time ‘window’ between the first and second vaccine doses) is now from 14 to 180 days.
The previous label recommendation called for vaccinations just 3-4 weeks apart.
The change to label claims has been possible through scientific data generated in Australian cattle populations, and represents a significant step for the grainfed beef industry.
The development will have implications right along the supply chain:
- Cattle producers supplying feeders to feedlots can now pre-vaccinate at the same time as other normal management practices at weaning, while still reaping rewards for premiums at sale time
- Feedlot operators can now feel safe in the knowledge that their traditional suppliers will have plenty of time to vaccinate pre-sale.
- Resellers can confidently stock the vaccine as it becomes part of standard cattle management rather than a ‘last minute rush order.’
Many Australian lotfeeders, including JBS Australia and Teys Australia, have been working hard to convince producers, through price premium incentives, to vaccinate pre-induction into feedyards.
One of the most common points of resistance to this has been the fact that animals need to be vaccinated two to three weeks before delivery.
Under the new label change, the greatly extended treatment period means the vaccine can be used as part of normal husbandry practices at weaning, rather than requiring a special muster for treatment.
Coopers Animal Health marketing manager Paul Speer said over the past couple of years, sales of the Bovilis vaccine had increased by more than 50pc as feedlots and backgrounders recognised the benefits it provided in helping to control BRD, thereby reducing morbidity and mortality.
The main barrier to use however has been the short window available to apply the vaccine prior to sale of the animal.
“By providing flexibility in the interval between doses, we’ve made it possible for cattle producers to more conveniently pre-vaccinate young cattle at a time that fits with other farm activities,” Mr Speer said.
“While we have been working hard with our pre-vaccination partners to ensure the vaccine is available to producers, this extension reinforces the work that we have been doing behind the scenes to make it easier to use this vaccine.”
Bovine Respiratory Disease causes between 50pc and 90pc of morbidity and mortality in Australian feedlots, and the disease is estimated to cost the Australian beef Industry $60 million annually.
BRD is a complex disease involving many contributing factors that, if combined, compromise the respiratory defences of affected cattle, allowing infection to establish in the lungs and produce severe, often fatal, pneumonia. Contributing factors include stressors such as transport, dietary changes, feedlot induction, pen competition and mixing of cattle from different sources.
Bovilis MH + IBR is a combination vaccine given subcutaneously that helps to control bacterial and viral causes of BRD. Controlling BRD has been proven to help cattle perform better in the feedlot, and reduce use of antibiotics.
Sources: ALFA/MLA; Coopers