Association between obesity and reduced body temperature in dogs

Abstract

Background: Industrialized nations are currently experiencing an obesity epidemic, the causes of which are not fully known. One possible mechanism of enhanced energy efficiency that has received almost no attention is a reduction in the metabolic cost of homeothermy, which could be achieved by a modest lowering of body core temperature. We evaluated the potential of this obesity-inducing mechanism in a canine model of the metabolic syndrome. Methods: We compared the rectal temperature of lean dogs and obese dogs by (a) conducting cross-sectional measurements in 287 dogs of many breeds varying greatly in body size, (b) conducting longitudinal measurements in individual dogs over 7-10 years and (c) tracking rectal temperature of lean and obese dogs at 3-h intervals for 48 consecutive hours in the laboratory. Results: We found that larger dogs have lower rectal temperatures than smaller dogs and that, for the same body mass, obese dogs have lower rectal temperatures than lean dogs. The results were consistent in the cross-sectional, longitudinal and aroundthe-clock measurements. Conclusion: These findings document an association between obesity and reduced body temperature in dogs and support the hypothesis that obesity in this and other species of homeotherms may result from an increase in metabolic efficiency achieved by a regulated lowering of body temperature.

Eye and Ear Temperature Using Infrared Thermography Are Related to Rectal Temperature in Dogs at Rest or With Exercise

“…Piccione et al (17) did observe breed differences with diurnal change in daytime and nighttime BT, which, as stated above, is sensitive to masking because of physical activity or environmental stimuli. Thus in the current study, the movement of the dogs in the AM to obtain the measurements may have influenced the morning BTs that was sustained throughout the day with subsequent measurement collection.…”

“…This study also reports observations of breed size differences in BT with all three methods resulting in Labrador Retrievers having a higher BT compared to Beagles, with no observed interaction between breed and time in the sedentary portion of the study. Other studies have reported an opposite observation of small breed dogs having a higher BT compared to larger breed dogs (17). It is unclear of the discrepancy between breed sizes between this study and others.…”

“…The daytime temperatures measured between 09:00 and 14:30 were obtained while the dogs were considered sedentary and did not exhibit the natural diurnal fluctuation of BT that normally increases 0.5–0.8°C from early morning (08:00–10:00) and peaks between 17:00 and 20:00 (17, 30, 31). This lack of diurnal fluctuation was observed across all three methods, and as shown in Figure 1, the temperatures were relatively consistent or slightly declined over the day.…”

“…The study was designed to examine BT of eye and ear in dogs of two different breeds (Labrador Retrievers and Beagles) at rest or following play-exercise using IRT technology compared to rectal temperature as the traditional standard method of measuring BT. Two different breeds of dogs were examined because BT differs with breed size (17). Ultimately, if the IRT eye method is successful, then the potential exists to use remote and non-contact IRT to monitor hyperthermia in the field in working dogs (possibly in real time) without disturbing work or performance.…”

Core temperature: a forgotten variable in energy expenditure and obesity?

“…), precluding the possibility that decreased SNS activity contributes to obesity, but consonant with a diminished thermogenic response to sympathetic stimulation . Obese dogs have recently been shown to have lower body temperatures as compared with lean dogs of the same body mass .…”