Effect of feed withdrawal on truck effluent, animal welfare, carcase characteristics and microbiological contamination of feedlot cattle

Summary

Truck effluent is considered a by-product of the beef industry and must be well-managed to minimize its effect on the environment. Possible management techniques include capture of effluent in truck tanks and trailers with disposal at approved discharge points. Withdrawing feed may also be a possible management strategy for truck effluent, however no research has occurred locally to determine the effects of this practice in feedlot cattle. The study compared four durations of feed withdrawal including 0, 4, 8, and 12 hours on truck effluent volume and composition, carcass characteristics, and microbiological contamination of feedlot cattle.

Objectives

(1) Determine the effect of duration of feedlot feed withdrawal on truck effluent volume and composition at defined distances between the feedlot and processing plant.
(2) Determine the effect of duration of feedlot feed withdrawal on animal welfare, carcass characteristics and microbiological contamination of feedlot cattle
(3) Determine seasonal differences in the effect of feed withdrawal on truck effluent volume, animal welfare, carcass characteristics, and microbiological contamination of feedlot cattle

Key findings

- Reduced duration of feed withdrawal increased hot carcass weight and liver glycogen levels without impacting meat quality.
- Compared to 0h of feed withdrawal, hot carcase weight decreased for 4, 8 and 12h by 1.2, 1.1 and 1.8kg, respectively.
- Of total effluent captured in tanks and trailers, approximately two-thirds was produced during the first half of the journey. Overall, there was no difference in effluent captured in tanks for the total journey for different feed withdrawal treatments.
- Loss from animals (cutaneous and respiratory evaporation) and truck (evaporation, convection, spillage) was impacted by duration of feed withdrawal, however the difference was small over the 545km haul (0 vs 12h, 68.2kg per truck). There was no statistical difference between 0 and 4 hours of feed withdrawal for loss.
- Total microbiological counts and the proportion of carcasses with microbiological contamination were not affected by duration of feed withdrawal.
- A variety of uses for the feedlot effluent from this project were explored including municipal sewer disposal, incorporation into standalone or red meat processor biogas facilities, and direct land application. Direct land application of effluent contingent on environmental licensing, land availability and infrastructure development for irrigation was determined to be the most appropriate use of effluent from this study.

Benefits to industry

The results of this trial provide a clear baseline for the volume and composition of effluent captured at multiple stops during a journey from feedlot to abattoir under Australian conditions. These results provide valuable data for future planning of means to capture, treat, and use feedlot cattle effluent produced during transportation.

Managing feed allocation to time of dispatch is an important consideration for lot feeders. This project provides an objective dataset to enable discussion with abattoir customers and supply chain participants on impacts of feed withdrawal on carcase traits and effluent.

MLA action

Presentation of the research have been made to industry at:
- Australian Lot Feeders' Association Smart Beef Conference 2021
- Australian Lot Feeders' Association Transportation & Lairage Webinar, 2022

Future research

Future development opportunities exist to use the results of this study to design methods to capture feedlot cattle effluent produced during transport and subsequently means to treat, prepare, and capture value from this resource. Whilst being conducted in domestic grain-fed heifers, future research could focus on alternative market categories of Australian feedlot cattle. It should be noted the results of this report are only relevant to feedlot production and not grazing systems.