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Objective

To compare the infrared thermographic appearance of bovine ears that had received contaminated growth promotant implants with ears that had received clean implants and ears without implants.

Design

Prospective study.

Animals

32 yearling crossbred beef steers with a mean weight of 322 kg (708 lbs).

Procedure

Contaminated (n = 16) and clean (16) implants were placed in the ears of feedlot cattle. Nonimplanted (n = 32) ears served as a within-animal control for thermographic comparisons. Images of rostral and caudal surfaces were obtained during a 21-day period, using an infrared thermal imaging radiometer. Repeated measures ANOVA was used to determine the relationship between mean temperature in a zone on the rostral surface of the ear and at 3 locations (proximal, middle, distal) on the caudal surface of the ear (response variables) with treatment (ears with contaminated implants or clean implants vs control ears with no implants), time (repeated day of measurement), and interactions among these variables.

Results

Significant temperature differences existed between ears with contaminated implants and control ears. Temperatures for ears with clean implants were significantly higher than control ears on day 2. At low ambient temperatures when the ears became wet, a greater temperature contrast was detected between ears with contaminated implants and control ears.

Conclusions and Clinical Relevance

Thermal imaging of the ears of feedlot cattle is a noninvasive diagnostic tool that can be used to identify cattle with abscesses caused by contaminated growth-promotant implants. (J Am Vet Med Assoc 1999;215:1320–1324)

Free access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To determine whether infrared thermographic images obtained the morning after overnight heat abatement could be used as the basis for diagnostic algorithms to predict subsequent heat stress events in feedlot cattle exposed to high ambient temperatures.

ANIMALS 60 crossbred beef heifers (mean ± SD body weight, 385.8 ± 20.3 kg).

PROCEDURES Calves were housed in groups of 20 in 3 pens without any shade. During the 6 am and 3 pm hours on each of 10 days during a 14-day period when the daily ambient temperature was forecasted to be > 29.4°C, an investigator walked outside each pen and obtained profile digital thermal images of and assigned panting scores to calves near the periphery of the pen. Relationships between infrared thermographic data and panting scores were evaluated with artificial learning models.

RESULTS Afternoon panting score was positively associated with morning but not afternoon thermographic data (body surface temperature). Evaluation of multiple artificial learning models indicated that morning body surface temperature was not an accurate predictor of an afternoon heat stress event, and thermographic data were of little predictive benefit, compared with morning and forecasted weather conditions.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated infrared thermography was an objective method to monitor beef calves for heat stress in research settings. However, thermographic data obtained in the morning did not accurately predict which calves would develop heat stress later in the day. The use of infrared thermography as a diagnostic tool for monitoring heat stress in feedlot cattle requires further investigation.

Full access
in American Journal of Veterinary Research