What Can We Learn from Good Feedlot Pen Checkers?

Background

The accuracy and timeliness of BRD diagnosis determines the likelihood of treatment success. Efforts have been made to develop systems to automatically detect sick feeder cattle, but feedlots continue to rely on pen checkers. Some pen checkers are very effective (and have lower re-pull and death rates) while others may require more experience or training to accurately identify truly ill cattle and improve cattle health outcomes. This project will examine what makes pen checkers successful. 

Objectives

Identify human and animal factors that influence the correct identification and decision making of feedlot cattle with BRD.  

• Characterize pen checking methodologies of effective pen riders based on different performance parameters. 

• Develop a video-based survey to evaluate how a broader sample of pen riders prioritize different animal-based factors when identifying and pulling sick cattle.  

• Evaluate differences in the decision-making process and success rate pen riders based on years of experience, pen riding technique, and how they prioritize clinical signs of disease. 

What they Did

Phase 1: 12 top pen checkers from several feedlots were fitted with a GoPro camera to record BRD cases, and a 2-way radio to communicate with a researcher outside the pen who recorded their observations. Detailed treatment records and biomarkers, temperatures and Whisper stethoscope readings were collected from animals pulled for treatment. These physiological measurements were linked to checkers’ observations and the clinical signs recorded upon being pulled. Their value for predicting the severity, treatment response, retreatment and death rates were assessed.

Phase 2: As part of an online survey, the GoPro videos were shown to pen checkers varying in age, gender, experience, technique (horse, walk, quad, etc.). They were shown video clips of animals showing obvious signs of disease, subtle signs (that later got pulled), subtle signs (that never got pulled), and no signs, and be asked which would you pull and why?

What they Learned

A limited number of clinical signs are consistently associated with a diagnosis of BRD based on different case definitions. Nose secretions, however, was highly associated with BRD, independent of the case definition used.

Abnormal eye expression (aka sunken or dopey eyes) was negatively associated to rectal temperatures ≥40°C, suggesting that this clinical sign should be regarded as less important among pen riders when pulling calves with BRD.

Clinical signs most strongly associated with a death outcome from BRD were flat tail (aka beaver tail, when the tail-head of the animal sits lower between the hip bones) and mouth secretions, while chronic cases were associated with calves showing abnormal respiration and nose secretions upon first pull.

The use of body temperature, blood lactate and lung auscultation as chute-side tests to diagnose BRD only showed a fair agreement with BRD outcomes, suggesting that more diagnostic tools did not improve the accuracy of the diagnostic, but rather they may add more confusion to the decision-making process.

Results from the survey showed agreement among pen checkers regarding specific clinical signs indicative of BRD.

Experience as a pen checker did not determine the accuracy of diagnosis of calves with BRD. Differences in their accuracy may be determined by the clinical signs considered critically important when diagnosing cattle with BRD, as most accurate pen riders considered body posture and head carriage as critically important, while less accurate pen riders gave more value to mouth and nose discharge.

Pen checkers remain an essential part of the detection of BRD in feedlots, whether in addition to technology or not, it seems there will always be a need for personnel to either interpret or treat sick animals. The variability we observed in the clinical presentation and diagnostic tests in our dataset may suggest that humans, in this case pen checkers, will indeed be needed in the assessment, validation, and treatment of BRD at the farm in the foreseeable future.

What It Means

• Rectal temperature, blood lactate, and lung auscultation score have slight agreement when diagnosing BRD.

• “Nose secretions” are significantly associated with a diagnosis of BRD based on the different case definitions, while “eye expression” is not. “Abnormal respiration” and “nose secretions” are most commonly present among chronic cases of BRD, while “flat tail” and “mouth secretions” are most commonly present among cases of BRD death. The relevance of these clinical signs when diagnosing BRD in the pen should be adjusted accordingly.

• Pen checkers with different age, experience and training generally prioritize labored breathing/altered respiration, slow-moving, and body posture/head carriage as signs of BRD.

• The more accurate pen riders considered “body posture” and “head carriage” as “critically important” clinical signs when diagnosing BRD. Less accurate pen riders put more emphasis on “labored breathing” and “altered respiratory rate”.