B.FLT.3006-Effect of liver defects on carcase characteristics, performance and health of feedlot cattle
The most common liver defects observed in feedlot cattle are liver abscess, liver fluke and hydatid cysts.
| Publication date: | 22 February 2022 |
| Project status: | Completed |
| Livestock species: | Grain-fed Cattle |
| Relevant regions: | National |
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Summary
This project was undertaken to determine the animal welfare, production and economic impacts of liver disease in feedlot cattle. Two main studies focused on 100-day Angus, 100-day mixed breed, and 300-day Wagyu cattle classes. Retrospective analysis of data from over four hundred thousand cattle slaughtered between 2014 and 2020 from one supply chain identified a decreasing trend in disease prevalence over time, and variable seasonal effects on abscessation, fluke and hydatid. Prospective data from over eleven thousand livers assessed on the slaughter floor identified severe liver abscessation as the most important disease impacting production parameters and carcase value.
Objectives
The final objectives, all of which were achieved for this project were as follows:
1. To develop a grading scheme for liver lesions in feedlot beef cattle in Australia and a kill floor data collection methodology for liver defects to ensure coordination between the abattoir, feedlot and research team.
2. To determine the prevalence, temporal patterns, and severity of different forms of liver pathology in feedlot cattle in Southeast Qld.
3. To determine the effect of different liver defects on the performance and health of cattle in the feedlot, on carcase characteristics.
4. To investigate the economic value of reducing liver defects for the Australian feedlot beef supply chain.
Key findings
The most significant liver defects in both studies were abscess, fluke and hydatid.
• The retrospective study showed decreased prevalence in liver defects over the time period, with variable seasonal effects on the prevalence of the defects across cattle classes.
• The prospective study determined a threshold level of liver abscessation of >20% of the organ affected indicating severe disease. This severe abscessation was associated with poorer performance, including reducing one or more of average daily gain (ADG), hot standard carcase weight (HSCW), dressing percentage, P8 fat, rib fat and carcase value across the different carcase types.
• It is recommended that producers and processors use the severity threshold of > 20% liver abscessation to assess for economic impacts on their supply chain.
• Notably hydatid was associated with poorer performance in Wagyu cattle, typically ~ 9.1kg lower HSCW, reduced dressing percentage, P8 and rib fat, and increased ossification.
Benefits to industry
This project provides current Australian data on the extent of and potential for economic and animal welfare impact from liver disease in feedlot cattle. Results from the study can be used to prioritise and inform management decisions and improve production and economic performance and animal welfare. The project developed a unique grading scheme for liver lesions that can be adopted for future R&D.
MLA action
Deployment of the grading scheme for liver defects in future industry R&D
• Further investigation on the economic impact of hydatids on the supply chain due the association of poorer performance in Wagyu cattle, typically ~ 9.1kg lower HSCW, reduced dressing percentage, P8 and rib fat, and increased ossification.
• Investigation of the feasibility for commercialization of a hydatid vaccine
Future research
Determination of the abscess causing microorganisms under different production conditions and with various interventions to reduce abscessation
• Future research is highly recommended on the epidemiological drivers, such as season, weather, geographic location of liver disease, particularly fluke and hydatid.
• Given the identification of a threshold for severe liver abscessation and its negative impact, research for strategies to prevent severe abscesses and its associated conditions is warranted to improve animal welfare and productivity.
• The negative associations between hydatid disease and Wagyu cattle performance parameters needs to examined in other production contexts, and a possible mechanism for the breed’s sensitivity to this parasite identified.
• Future R&D should extend the prospective collection methodology across different supply chains in other geographic areas to determine a more holistic impact of liver disease on the Australian beef feedlot supply chain,
• An economic calculator could be developed allowing various supply chains and producers to input their price grids to assess the economic impact of liver disease and associated conditions, thus guiding management decisions.
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For more information: Contact Project Manager: Joe McMeniman |
