Regulation of heat loss in the duck by vasomotion in the bill

Hagan, Ann A.; Heath, James E.

doi:10.1016/0306-4565(80)90006-6

Cited by 76 publications

(80 citation statements)

References 10 publications

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“…These results of our study confirmed the studies [19] and [18]. [20] and [21] consider the bill as an important part of the body for the assessment of bird thermal status. Authors [12] notice, that also shank as un-feathered part of bird body is suitable for evaluation of thermal status of birds.…”

Section: Discussionsupporting

confidence: 92%

Thermal profile of broilers infected by Eimeria tenella

Knı́žková¹,

Kunc²,

Langrová³

et al. 2018

Proceedings of the 2018 International Conference on Quantitative InfraRed Thermography

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In study, infrared thermography (IRT) was assessed as a means of detecting the changes in body temperature in poultry coccidiosis, as well as determining IRT used in imaging and measuring the regional changes in skin temperature that occur in the poultry during this infection. Broilers were inoculated with 5×10 2 or 1×10 3 oocysts of Eimeria tennella.The group of control animals remained non-inoculated throughout the study. The study showed that coccidiosis affected temperature homeostasis in animals significantly. Body surface temperature decreases significantly (p<0.05). IRT is a promising tool that may provide a more objective an quantitative information about thermal status of animals.

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Section: Discussionsupporting

confidence: 92%

Thermal profile of broilers infected by Eimeria tenella

Knı́žková¹,

Kunc²,

Langrová³

et al. 2018

Proceedings of the 2018 International Conference on Quantitative InfraRed Thermography

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“…Although bill morphology is strongly associated with diet and foraging niche [4,5], there is also growing evidence of its significance in body temperature regulation [6][7][8] and heat exchange via the bill has been found in all species investigated to date [9]. The keratinized outer layer of the bill, the rhamphotheca, covers an extensive network of blood vessels into which blood may be pumped during exposure to high temperatures to achieve dissipation of excess metabolic heat via radiation and convection [10]. Thus, for example, the Toco toucan, Ramphastos toco can shunt up to 60% of its heat load through the bill when air temperatures exceed 28°C, reducing the need for evaporative cooling [6].…”

Section: Introductionmentioning

confidence: 99%

Spatial variation in avian bill size is associated with humidity in summer among Australian passerines

Gardner

Symonds

Joseph

et al. 2016

Clim Chang Responses

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Background: Climate imposes multiple selection pressures on animal morphology. Allen's Rule proposes that geographic variation in the appendage size of endotherms, relative to body size, is linked to climatic variation, thereby facilitating heat exchange and body temperature regulation. Thus relatively larger appendages tend to be found in animals in warmer climates. Despite growing understanding of the role of the avian bill as an organ for heat exchange, few studies have tested the ecological significance of bill size for heat dissipation across species and environmental gradients. Amongst those that have, most have focused on the relationship with ambient temperature, but there is growing evidence that humidity also has a strong influence on heat dissipation. In particular, increasing humidity reduces the potential for evaporative cooling, favouring radiative and convective heat loss via the bill, and hence potentially favouring larger bills in humid environments. Here, we used phylogenetically-controlled analyses of the bill morphology of 36 species of Australian passerines to explore the relationship between bill size and multiple aspects of climate. Results: Humidity during the hot summer months (December-February) was positively associated with relative bill surface area across species. There was no overall association between bill size and summer temperatures per se, but the association with humidity was mediated by temperature, with a significant interaction indicating stronger associations with humidity at cooler summer temperatures. This is consistent with the idea that larger bills may become disadvantageous in humid conditions as ambient temperature approaches body temperature. Relative bill size was similar among closely related species, with phylogeny explaining 63.3% of the variance, and there was significant variation among species in their response to humidity. However, the relationship between relative bill size and humidity was not associated with phylogeny.

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“…Peripheral heat loss is regulated by controlling blood flow to specific regions of the body surface, which alters surface temperature and thus the temperature differential driving heat dissipation (Klir and Heath, 1994;Mauck et al, 2003). These 'thermal windows' are typically poorly insulated, and include the ears, feet and nose of mammals (Klir and Heath, 1992), or the bill and feet of birds (Kilgore and Schmidt-Nielsen, 1975;Baudinette et al, 1976;Hagan and Heath, 1980). Despite its known importance for thermoregulation in general, the role and control of peripheral heat loss from thermal windows during hypoxic T b depression has received very little attention (cf.…”

Section: Introductionmentioning

confidence: 99%

Body temperature depression and peripheral heat loss accompany the metabolic and ventilatory responses to hypoxia in low and high altitude birds

Scott

Cadena

Tattersall

et al. 2008

Journal of Experimental Biology

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SUMMARYThe objectives of this study were to compare the thermoregulatory, metabolic and ventilatory responses to hypoxia of the high altitude bar-headed goose with low altitude waterfowl. All birds were found to reduce body temperature (T b ) during hypoxia, by up to 1-1.5°C in severe hypoxia. During prolonged hypoxia, T b stabilized at a new lower temperature. A regulated increase in heat loss contributed to T b depression as reflected by increases in bill surface temperatures (up to 5°C) during hypoxia. Bill warming required peripheral chemoreceptor inputs, since vagotomy abolished this response to hypoxia. T b depression could still occur without bill warming, however, because vagotomized birds reduced T b as much as intact birds. Compared to both greylag geese and pekin ducks, bar-headed geese required more severe hypoxia to initiate T b depression and heat loss from the bill. However, when T b depression or bill warming were expressed relative to arterial O 2 concentration (rather than inspired O 2 ) all species were similar; this suggests that enhanced O 2 loading, rather than differences in thermoregulatory control centres, reduces T b depression during hypoxia in bar-headed geese. Correspondingly, bar-headed geese maintained higher rates of metabolism during severe hypoxia (7% inspired O 2 ), but this was only partly due to differences in T b . Time domains of the hypoxic ventilatory response also appeared to differ between bar-headed geese and low altitude species. Overall, our results suggest that birds can adjust peripheral heat dissipation to facilitate T b depression during hypoxia, and that bar-headed geese minimize T b and metabolic depression as a result of evolutionary adaptations that enhance O 2 transport.

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Regulation of heat loss in the duck by vasomotion in the bill

Cited by 76 publications

References 10 publications

Thermal profile of broilers infected by Eimeria tenella

Thermal profile of broilers infected by Eimeria tenella

Spatial variation in avian bill size is associated with humidity in summer among Australian passerines

Body temperature depression and peripheral heat loss accompany the metabolic and ventilatory responses to hypoxia in low and high altitude birds

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