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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 the relationship between ambient temperature and mean body surface temperature (MBST) measured by use of infrared thermography (IRT) and to evaluate the ability of IRT to detect febrile responses in pigs following inoculation with Actinobacillus pleuropneumoniae.

Animals—28 crossbred barrows.

Procedures—Pigs (n = 4) were subjected to ambient temperatures ranging from 10 to 32 C in an environmental chamber. Infrared thermographs were obtained, and regression analysis was used to determine the relationship between ambient temperature and MBST. The remaining pigs were assigned to groups in an unbalanced randomized complete block design (6 A pleuropneumoniae-inoculated febrile pigs [increase in rectal temperature ≥ 1.67 C], 6 A pleuropneumoniae-inoculated nonfebrile pigs [increase in rectal temperature < 1.67 C], and 12 noninoculated pigs). Infrared thermographs and rectal temperatures were obtained for the period from 2 hours before to 18 hours after inoculation, and results were analyzed by use of repeated-measures ANOVA.

Results—A significant linear relationship was observed between ambient temperature and MBST (slope, 0.40 C). For inoculated febrile pigs, a treatment X method interaction was evident for rectal temperature and MBST, whereas inoculated nonfebrile pigs only had increased rectal temperatures, compared with noninoculated pigs. A method X time interaction resulted from the longer interval after inoculation until detection of an increase in MBST by use of IRT.

Conclusions and Clinical Relevance—Infrared thermography can be adjusted to account for ambient temperature and used to detect changes in MBST and radiant heat production attributable to a febrile response in pigs. (Am J Vet Res 2001;62:676–681)

Full access
in American Journal of Veterinary Research