A comprehensive index for assessing environmental stress in animals

Mader, T. L., Johnson, L. J. and Gaughan, J. B. (2010) A comprehensive index for assessing environmental stress in animals. Journal of Animal Science, 88 6: 2153-2165. doi:10.2527/jas.2009-2586

Author Mader, T. L.
Johnson, L. J.
Gaughan, J. B.
Title A comprehensive index for assessing environmental stress in animals
Journal name Journal of Animal Science   Check publisher's open access policy
ISSN 0021-8812
Publication date 2010-06-01
Year available 2010
Sub-type Article (original research)
DOI 10.2527/jas.2009-2586
Open Access Status
Volume 88
Issue 6
Start page 2153
End page 2165
Total pages 13
Place of publication Savoy, IL., U.S.A.
Publisher American Society of Animal Science
Language eng
Abstract Numerous models and indices exist that attempt to characterize the effect of environmental factors on the comfort of animals and humans. Heat and cold indices have been utilized to adjust ambient temperature (Ta) for the effects of relative humidity (RH) or wind speed (WS) or both for the purposes of obtaining a "feels-like" or apparent temperature. However, no model has been found that incorporates adjustments for RH, WS, and radiation (RAD) over conditions that encompass hot and cold environmental conditions. The objective of this study was to develop a comprehensive climate index (CCI) that has application under a wide range of environmental conditions and provides an adjustment to Ta for RH, WS, and RAD. Environmental data were compiled from 9 separate summer periods in which heat stress events occurred and from 6 different winter periods to develop and validate the CCI. The RH adjustment is derived from an exponential relationship between Ta and RH with temperature being adjusted up or down from an RH value of 30%. At 45°C, the temperature adjustment for increasing RH from 30 to 100% equals approximately 16°C, whereas at -30°C temperature adjustments due to increasing RH from 30 to 100% equal approximately -3.0°C, with greater RH values contributing to a reduced apparent temperature under cold conditions. The relationship between WS and temperature adjustments was also determined to be exponential with a logarithmic adjustment to define appropriate declines in apparent temperature as WS increases. With this index, slower WS results in the greatest change in apparent temperature per unit of WS regardless of whether hot or cold conditions exist. As WS increases, the change in apparent temperature per unit of WS becomes less. Based on existing windchill and heat indices, the effect of WS on apparent temperature is sufficiently similar to allow one equation to be utilized under hot and cold conditions. The RAD component was separated into direct solar radiation and ground surface radiation. Both of these were found to have a linear relationship with Ta. This index will be useful for further development of biological response functions, which are associated with energy exchange, and improving decision-making processes, which are weather-dependent. In addition, the defined thresholds can serve as management and environmental mitigation guidelines to protect and ensure animal comfort.
Keyword Bioclimatic index
Cold stress
Domestic livestock
Environmental factor
Environmental model
Heat stress
Animal welfare
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Agriculture and Food Sciences
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Citation counts: TR Web of Science Citation Count  Cited 47 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 48 times in Scopus Article | Citations
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Created: Sun, 30 May 2010, 10:04:22 EST