Evaluation of a Remote Early Disease Identification system to detect bovine respiratory disease in beef cattle in commercial Australian feeding operations – Site 1 & 2

Summary

Bovine respiratory disease (BRD) affects the health and performance of feedlot cattle in the United States as well as Australia. Current diagnostic methods for detecting BRD have a poor specificity and sensitivity. The objectives of this project were to evaluate a remote early disease identification (REDI) system to diagnose BRD versus conventional (CON) disease detection and diagnosis of feedlot cattle and determine the economic impact of BRD on feedlot performance and carcass characteristics. Research occurred at two Southern Australian feedlots.

At Site 1 a total of 2,628 steers were allocated to each treatment group for each block of the experiment (6 total). Calves were followed from allocation to slaughter. Results showed no statistical differences between treatment groups for lung lesions, mortalities, rejects, or performance characteristics. A significant difference was found for initial BRD treatment between REDI vs CON (32% vs 8%).

A significant difference (P < 0.05) was found in treatment costs, with REDI costing an average $18.58 per head and Control costing $4.14. The net return per steer was $164.72 for control and $152.29 for REDI.

At Site 2, six replicates of cattle were enrolled in the trial. Calves were randomly assigned to one diagnostic modality (REDI vs CON) with 300 steers per pen. Health and performance outcomes between the two diagnostic modalities were compared.

The REDI system monitored calves for the first 55 days on trial. Calves initially treated for BRD were greater (P < 0.05) in CON (44% ± 0.07) compared to REDI (27% ± 0.05). Second BRD treatments were greater (P < 0.05) in REDI compared to CON. Calves initially treated for BRD had greater (P < 0.05) normal lung scores (75% ± 0.04) in CON compared to REDI (70% ± 0.04) and REDI had greater moderate lung scores (26% ± 0.05) compared to CON (21% ± 0.04) during the REDI monitoring period. Calves not treated for BRD had greater (P < 0.05) normal lung scores (75% ± 0.04) in CON compared to REDI (70% ± 0.04), and REDI had greater (P < 0.05) moderate lung scores (28% ± 0.05) compared to CON (24% ± 0.04). There were no differences in severe lung scores, mortalities, rejects, or performance between modalities.

The results indicate that REDI can detect more calves with moderate lung scores compared to CON with a lesser treatment rate. The REDI algorithms were generated for U.S. cattle and further research to calibrate and optimize these algorithms for greater accuracy of detecting BRD in the Australian environment is warranted.