B.FLT.4017 - The effect of lairage duration on carcass quality, yield and microbiological status

Summary

The period of time and location where cattle are housed between arrival at an abattoir and slaughter is termed ‘lairage’. Cattle are held in lairage to rest following transportation, to accumulate in numbers to facilitate a consistent supply of cattle to the slaughter floor during business hours, to reduce the volume of contents in the gastrointestinal tract prior to slaughter, and to allow scheduling of slaughter times for specific vendors and cattle types for more efficient chilling and boning room schedules. Lairage is also a critical control point for food safety and animal welfare, as it provides an area for ante-mortem inspection by on-plant veterinarians to ensure the cattle are free from clinical signs of disease and any potential contamination that could affect the slaughtered carcase.

In Australian abattoirs, cattle have access to water during lairage. Rarely are cattle provided access to feed during lairage. The facilities in lairage are diverse and may include compacted earth or concrete floors, shaded or unshaded pens, and wooden or metal fences. The duration of time feedlot cattle spend in lairage in Australian conditions is highly variable and can range between 2–36 hours, but more commonly ranges between 12–24 hours. Feedlot cattle are commonly transported from the feedlot to the abattoir the day prior to slaughter and hence spend overnight in lairage on the day prior to slaughter. This practice results in a period of time off feed that often exceeds 12 hours prior to slaughter. Interestingly, this practice has been largely eliminated in the USA following the 1991 US Beef Quality Audit that ‘rough handling and holding cattle overnight or over the weekend causes about 20% of dark-cutters (NCBA, 1992).

However, the duration of lairage for feedlot cattle in Australia has largely remained unchanged over the past 30 years and the practice of overnight lairage of feedlot cattle is still widely accepted in Australia.

The objective of this project was to measure the effect of the duration of time feedlot cattle spend at an abattoir prior to processing, also known as duration of lairage, on carcase yield and quality, animal welfare, and food safety parameters. Fourteen replicates including 2,226 steers were used to compare three durations of lairage including short (four hours at abattoir), mid (16.5 hours) and long (26.5 hours).

Objectives

1. Determine the effect of lairage duration on carcase yield including hot carcase weight, dressing percentage, and muscle glycogen levels.
2. Determine the effect of lairage duration on animal welfare through measurement of liver and muscle glycogen levels, ultimate pH, and meat colour.
3. Determine the effect of lairage duration on food safety parameters.
4. Effectively communicate the results of this research to stakeholders through publications and presentations.

Key findings

- Reduced lairage duration is possible in a large-scale commercial feedlot and abattoir environment.
- Short duration lairage yielded a 7.4kg advantage (P ≤ 0.05) in hot carcase weight as compared to mid-duration lairage.
- Short duration lairage yielded a 6.2kg advantage (P ≤ 0.05) in hot carcase weight as compared to long-duration lairage.
- The duration of lairage had a significant (P ≤ 0.05) effect on packed cell volume, meaning that cattle exposed to longer duration of lairage were more dehydrated as compared to cattle exposed to shorter duration lairage.
- The duration of lairage had a significant (P ≤ 0.05) effect on levels of glycogen in the liver, meaning that cattle exposed to longer duration of lairage mobilised glycogen reserves in their livers to maintain blood glucose status.
- Total microbiological counts (standard plate counts, coliform counts, E.coli counts, and Salmonella spp. detection) and the proportion of carcases with microbiological contamination were not affected by duration of lairage (P > 0.05).
- There was no effect of lairage duration on meat quality or food safety parameters.

Benefits to industry

This project demonstrated that reduced lairage duration provided a significant benefit in the profitability across the supply chain and improved sustainability by increasing the hot carcase weight per individual animal. Additionally, this project demonstrated the clear animal welfare benefits associated with implementing short duration lairage.

MLA action

The project results have been disseminated to the feedlot industry through:

- a Feedlot industry presentation at the Australian Lot Feeders' Association Beef Ex Conference, Brisbane, October, 2022
- two presentations to the Federal Departments on-plant veterinarians
- presentation to the ALFA/MLA consulting veterinarian and nutritionist meeting.

MLA is currently funding MLA Project B.FLT.1022, which will evaluate short duration lairage responses in domestic, short-fed export and long-fed export grain-fed market categories during winter/spring conditions.

Future research

Future work should focus on opportunities to simplify the logistical challenges associated with implementing short duration lairage in a commercial environment including electronic submission of regulatory paperwork such as National Vendor Declarations, transport scheduling, ante-mortem inspection scheduling, and improving coat cleanliness prior to abattoir arrival to reduce washing intervals required prior to slaughter during winter conditions.