Can a Routine Chute-Side Lung Ultrasound Be Performed on Cattle Upon Arrival at the Feedlot?

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Upon arrival at the feedlot, cattle groups are assigned a risk of developing respiratory disease based on source, history and visual inspection. Overall, cattle in higher-risk groups are more likely to develop respiratory disease than those in lower-risk groups, and assigning risk helps determine which antimicrobials to use, especially for higher-risk groups. Yet it is unclear whether thoracic ultrasound (TUS) could inform this assessment more accurately and support more judicious antimicrobial use.

Ultrasound has been extensively used in cattle, mostly for early pregnancy checking. It is also used, to a lesser extent, to measure rib eye, marbling and other traits to calculate EPDs, especially in seedstock cattle

More recently, thoracic ultrasound has been shown to detect lung consolidation caused by respiratory disease. However, the degree to which lung consolidation seen in TUS images relates to and reflects clinical signs of pneumonia is inconsistent. This has varied across studies and among veal, dairy and beef calves.

To date, studies focused on identifying lung consolidation in feedlot cattle have focused on animals already diagnosed with respiratory disease, but none have assessed if the cranioventral lung fields, where early respiratory disease lesions occur, can be scanned safely and efficiently during routine arrival processing. If so, future studies could assess whether this would be useful to consider when assigning risk. Therefore, this study will focus on whether a chute-side ultrasound scan during at-arrival processing is practical and can be done efficiently.

Objectives

• Standardize a chute-side ultrasound protocol for feeder cattle and test if the cranioventral portions of the lung can be accessed safely.
• Assess the time it takes to complete the scan, its duration, the image/video quality, operator safety and effects on processing workflow.
• Define standard image quality criteria for future validation studies.

What They Will Do

The research group will conduct this study at one or more commercial feedlots during the fall. During processing, they will enrol lightweight, high-risk beef feeder cattle, approximately 500-600 lbs at arrival.

Each animal will receive a single ultrasound attempt, including the cranioventral portions. Imaging will be done using a portable ultrasound unit with a linear-array probe, starting at approximately 3.5 MHz and 20-30 cm depth, with settings refined during field testing to optimize image quality.

Researchers will determine whether the exam can be done, how long it takes and what images can be obtained.

Implications

To later assess whether TUS can inform better risk assessment and use of antimicrobials, it is important to first determine whether it can be done at arrival processing without interfering with the workflow.