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The present paper made the heat balance equation (HBE) for nude or minimally clad subjects a linear function of mean skin temperature ( t) by applying new equations for sweating efficiency ( η) and thermoregulatory sweat rate ( S). As the solution of the HBE, the equation predicting t was derived and used for a heat strain scale of subjects. The η was proportional to the reciprocal of S/ E ( S, sweat rate; E maximum evaporative capacity) and the S was proportional to t with a parameter of the sweating capacity of the subject. The errors of predicted t from observations due to the approximation of η were examined based on experimental data conducted on eight young male subjects. The value of errors of t was −0.10 ± 0.42 °C (mean ± sample standard deviation (SSD)). We aim to apply the predicted t of a subject at a level of sweating capacity as a heat strain scale of a function of four environmental factors (dry- and wet-bulb temperatures, radiation, and air velocity) and three human factors (metabolic rate, sweating capacity, and clothing (≤0.2clo)). [ABSTRACT FROM AUTHOR]

The purpose of this paper is to develop a database of tissue composition, distribution, volume, surface area, and skin thickness from anatomically correct human models, the virtual family. These models were based on high-resolution magnetic resonance imaging (MRI) of human volunteers, including two adults (male and female) and two children (boy and girl). In the segmented image dataset, each voxel is associated with a label which refers to a tissue type that occupies up that specific cubic millimeter of the body. The tissue volume was calculated from the number of the voxels with the same label. Volumes of 24 organs in body and volumes of 7 tissues in 10 specific body regions were calculated. Surface area was calculated from the collection of voxels that are touching the exterior air. Skin thicknesses were estimated from its volume and surface area. The differences between the calculated and original masses were about 3 % or less for tissues or organs that are important to thermoregulatory modeling, e.g., muscle, skin, and fat. This accurate database of body tissue distributions and geometry is essential for the development of human thermoregulatory models. Data derived from medical imaging provide new effective tools to enhance thermal physiology research and gain deeper insight into the mechanisms of how the human body maintains heat balance. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editors discuss the contents within the issue including articles on topics such as climate change, heat stress and its effects on spontaneous abortion and still-births in pregnant women in Ghana, and possible loss in work ability due to heat stress.

Various human heat stress indices have been developed to relate atmospheric measures of extreme heat to human health impacts, but the usefulness of different indices across various health impacts and in different populations is poorly understood. This paper determines which heat stress indices best fit hospital admissions for sets of cardiovascular, respiratory, and renal diseases across five Australian cities. We hypothesized that the best indices would be largely dependent on location. We fit parent models to these counts in the summers (November-March) between 2001 and 2013 using negative binomial regression. We then added 15 heat stress indices to these models, ranking their goodness of fit using the Akaike information criterion. Admissions for each health outcome were nearly always higher in hot or humid conditions. Contrary to our hypothesis that location would determine the best-fitting heat stress index, we found that the best indices were related largely by health outcome of interest, rather than location as hypothesized. In particular, heatwave and temperature indices had the best fit to cardiovascular admissions, humidity indices had the best fit to respiratory admissions, and combined heat-humidity indices had the best fit to renal admissions. With a few exceptions, the results were similar across all five cities. The best-fitting heat stress indices appear to be useful across several Australian cities with differing climates, but they may have varying usefulness depending on the outcome of interest. These findings suggest that future research on heat and health impacts, and in particular hospital demand modeling, could better reflect reality if it avoided “all-cause” health outcomes and used heat stress indices appropriate to specific diseases and disease groups. [ABSTRACT FROM AUTHOR]

Heat stress is one of the environmental factors influencing the health of individuals and the wider population. There is a large body of research to document significant increases in mortality and morbidity during heat waves all over the world. This paper presents key results of research dealing with heat-related mortality (HRM) in various cities in Poland which cover about 25% of the country’s population. Daily mortality and weather data reports for the years 1991-2000 were used. The intensity of heat stress was assessed by the universal thermal climate index (UTCI). The research considers also the projections of future bioclimate to the end of twenty-first century. Brain storming discussions were applied to find necessary adaptation strategies of healthcare system (HCS) in Poland, to minimise negative effects of heat stress. In general, in days with strong and very strong heat stress, ones must expect increase in mortality (in relation to no thermal stress days) of 12 and 47%, respectively. Because of projected rise in global temperature and heat stress frequency, we must expect significant increase in HRM to the end of twenty-first century of even 165% in comparison to present days. The results of research show necessity of urgent implementation of adaptation strategies to heat in HCS. [ABSTRACT FROM AUTHOR]

Heat stress (HS) negatively affects various industries that rely on animal husbandry, particularly the dairy industry. A better understanding of metabolic responses in HS dairy cows is necessary to elucidate the physiological mechanisms of HS and offer a new perspective for future research. In this paper, we review the current knowledge of responses of body metabolism (lipid, carbohydrate, and protein), endocrine profiles, and bovine mammary epithelial cells during HS. Furthermore, we summarize the metabolomics and proteomics data that have revealed the metabolite profiles and differentially expressed proteins that are a feature of HS in dairy cows. Analysis of metabolic changes and 'omics' data demonstrated that HS is characterized by reduced lipolysis, increased glycolysis, and catabolism of amino acids in dairy cows. Here, analysis of the impairment of immune function during HS and of the inflammation that arises after long-term HS might suggest new strategies to ameliorate the effects of HS in dairy production. [ABSTRACT FROM AUTHOR]

Aimed at climate-responsive urban design for tropical areas, the paper attempts to answer the question whether the site-related context affects in some way the perceptual assessment of the microclimate by users of outdoor spaces. Our hypothesis was that visual cues resulting from urban design are important components of the outdoor thermal perception. Monitoring was carried out alongside the administration of standard comfort questionnaires throughout summer periods in 2012-2015 in pedestrian areas of downtown Rio de Janeiro (22° 54 10 S, 43° 12 27 W), Brazil. Campaigns took place at different points, pre-defined in respect of urban geometry attributes. For the measurements, a Davis Vantage Pro2 weather station was employed to which a gray globe thermometer was attached. Two thermal indices were used for assessing the overall meteorological conditions and comfort levels in the outdoor locations: physiological equivalent temperature (PET) and universal thermal climate index (UTCI). Our results suggest that thermal sensation in Rio depends to a large extent on the thermal environment as described by air temperature, PET, or UTCI, and that urban geometry (expressed by the sky-view factor (SVF)) may modify this relationship with increased building density associated to warmer sensation votes under moderate heat stress conditions. This relationship however reverses under strong heat stress with warmer sensations in less obstructed locations, and disappears completely under still higher heat stress, where meteorological conditions, and not the site's SVF, will drive thermal sensation. [ABSTRACT FROM AUTHOR]

Environmental health hazards faced by farmers, such as exposure to extreme heat stress, are a growing concern due to global climate change, particularly in tropical developing countries. In such environments, farmers are considered to be a population at risk of environmental heat exposure. The situation is exacerbated due to their farming methods that involve the use of primitive equipment and hard manual labour conducted in full sunshine under hot and humid conditions. However, there is inadequate information about the extent of heat exposure to such farmers, both at the household and farm levels. This paper presents results from a study assessing environmental heat exposure on rural smallholder farmers in Bawku East, Northern Ghana. From January to December 2013, Lascar USB temperature and humidity sensors and a calibrated Questemp heat stress monitor were deployed to farms and homes of rural farmers at Pusiga in Bawku East to capture farmers' exposure to heat stress in both their living and working environments as they executed regular farming routines. The Lascar sensors have the capability to frequently, accurately and securely measure temperature and humidity over long periods. The Questemp heat stress monitor was placed in the same vicinity and showed strong correlations to Lascar sensors in terms of derived values of wet-bulb globe temperature (WBGT). The WBGT in the working environment of farmers peaked at 33.0 to 38.1 °C during the middle of the day in the rainy season from March to October and dropped to 14.0-23.7 °C in the early morning during this season. A maximum hourly WBGT of 28.9-37.5 °C (March-October) was recorded in the living environment of farmers, demonstrating little relief from heat exposure during the day. With these levels of heat stress, exposed farmers conducting physically demanding outdoor work risk suffering serious health consequences. The sustainability of manual farming practices is also under threat by such high levels of heat exposure. [ABSTRACT FROM AUTHOR]

In order to contribute to the sustainability of the outdoor environment, knowledge about the urban thermal bioclimate should be transferred into climatic guidelines for planning. The general framework of this study responds to the need of analyzing thermal bioclimate in Mediterranean climate regions and its influence as an urban design factor. The paper analyzes the background of the urban climate and thermal bioclimate conditions in Barcelona (Spain), through the effect of shade conditions and wind speed variations. Simulations of shade and wind speed variations were performed to evaluate changes in thermal bioclimate due to modifications in urban morphology. Air temperature, relative humidity, wind speed, and solar radiation for the period from January, 2001 to January, 2015 were used to calculate physiologically equivalent temperature (PET) using the RayMan model. The results demonstrate that shade is the most important strategy to improve urban microclimatic conditions. In Barcelona, human thermal comfort conditions can be improved by shade and wind speed increase in terms of PET above 23 °C and by a wind speed decrease for thresholds of PET below 18 °C. Heat stress situations can be mitigated by shade and wind speed increase in conditions above 35 and 45 °C, respectively. The results of the study are an important contribution for urban planners, due to their possibilities and potential for the description of microclimatic conditions in Mediterranean climate regions. The knowledge is useful for improved human thermal comfort conditions, from the suitable configuration of urban form and architecture. [ABSTRACT FROM AUTHOR]

This paper presents a study to develop a heat index, for use in hot and humid sub-tropical climate in Hong Kong. The study made use of hospitalization data and heat stress measurement data in Hong Kong from 2007 to 2011. The heat index, which is called Hong Kong Heat Index (HKHI), is calculated from the natural wet bulb temperature, the globe temperature, and the dry bulb temperature together with a set of coefficients applicable to the high humidity condition in the summer of Hong Kong. Analysis of the response of hospitalization rate to variation in HKHI and two other heat indices, namely Wet Bulb Globe Temperature (WBGT) and Net Effective Temperature (NET), revealed that HKHI performed generally better than WBGT and NET in reflecting the heat stress impact on excess hospitalization ratio in Hong Kong. Based on the study results, two reference criteria of HKHI were identified to establish a two-tier approach for the enhancement of the heat stress information service in Hong Kong. [ABSTRACT FROM AUTHOR]

The aim of this paper was to study qualitatively and quantitatively the thermal perception and corresponding heat stress conditions that prevail in two schoolyards in a coastal city in central Greece. For this purpose, meteorological parameters (i.e., wind speed, temperature, relative humidity, solar radiation) were recorded at 70 and 55 measuring points in the schoolyards, from 14:00 to 15:30 local time, during May and June of 2011. The measuring points were distributed so as to get measurements at points (a) directly exposed to the sun, (b) under the shadow of trees and building structures, and (c) near building structures. Cluster analysis was applied to group observations and revealed places that are microclimatically homogeneous. Thermal perception and heat stress conditions were assessed by means of the physiologically equivalent temperature (PET, °C), and the results are presented in relevant charts. The impact of material's albedo, radiation's reflection by structures and obstacles, and different tree species on thermal perception and heat stress conditions was also assessed. The analysis showed that trees triggered a reduction of incident solar radiation that ranged between 79 and 94 % depending on tree's species, crown dimension, tree height, and leaf area. PET values were mainly affected by solar radiation and wind speed. Trees caused a reduction of up to 37 % in PET values, while a 1-m s increase in wind speed triggered a reduction of 3.7-5.0 °C in PET value. The effective shading area in the two schoolyards was small, being 27.5 and 11 %. The results of this study could be exploited by urban planning managers when designing or improving the outdoor environment of a school complex. [ABSTRACT FROM AUTHOR]

This paper presents a new thermal stress index for dairy cows in inter-tropical regions, with special mention to the semi-arid ones. Holstein cows were measured for rectal temperature ( T), respiratory rate ( F) and rates of heat exchange by convection ( C), radiation ( R), skin surface evaporation ( E) and respiratory evaporation ( E) in the north eastern region of Brazil, after exposure to sun for several hours. Average environmental measurements during the observations were air temperature ( T) 32.4 °C (24.4-38.9°), wind speed ( U) 1.8 m.s (0.01-11.0), relative humidity 63.6 % (36.8-81.5) and short-wave solar radiation 701.3 W m (116-1,295). The effective radiant heat load (ERHL) was 838.5 ± 4.9 W m. Values for the atmospheric transmittance ( τ) were also determined for tropical regions, in order to permit adequate estimates of the solar radiation. The average value was τ = 0.611 ± 0.004 for clear days with some small moving clouds, with a range of 0.32 to 0.91 in the day period from 1000 to 1300 hours. Observed τ values were higher (0.62-0.66) for locations near the seacoast and in those regions well-provided with green fields. Effects of month, location and time of the day were all statistically significant ( P < 0.01). A total of 1,092 data were obtained for cows exposed for 1 to 8 h to sun during the day; in 7 months (February, March, April, July, August, September and November), 4 days per month on the average. A principal component analysis summarised the T, F, C, R, E and E measurements into just one synthetic variable ( y); several indexes were then obtained by multiple regression of y on the four environmental variables and its combinations, by using Origin 8.1 software (OriginLab Corp.). The chosen equation was the index of thermal stress for cows, ITSC = 77.1747 + 4.8327 T − 34.8189 U + 1.111 U + 118.6981 P − 14.7956 P − 0.1059 ERHL with r = 0.812. The correlations of ITSC with T, F, C, E, R and E were 0.275, 0.255, −0.493, −0.647, −0.818 and 0.075, respectively. Correlations of the index with the physiological variables are presented, and ITSC is compared to three other indexes. [ABSTRACT FROM AUTHOR]

This paper presents evaluation of a plan for surveillance of and controlling the effects of heat-related mortality (PSCEHW), implemented in Madrid in 2004 through a time series analysis conducted with ARIMA modeling. From the public health point of view, prevention plans should be implemented as adaptive measures to heat waves. In 2003, the impact attributable to the heat wave was an increase in mortality per °C of 22.39 %. All heat waves since 2003 have been of lower intensity, and yet, in 2005 there was a heat wave of lower intensity that had a greater impact, i.e. an increase in mortality per °C of 45.71 %. With the methodology used here, we cannot say whether implementation of PSCEHW has resulted in a decrease of mortality attributable to high temperatures in the city of Madrid. [ABSTRACT FROM AUTHOR]

Several studies have examined the relationship of high and low air temperatures to cardiovascular mortality in the Czech Republic. Much less is understood about heat-/cold-related cardiovascular morbidity and possible regional differences. This paper compares the effects of warm and cold days on excess mortality and morbidity for cardiovascular diseases (CVDs) in the city of Prague and a rural region of southern Bohemia during 1994-2009. Population size and age structure are similar in the two regions. The results are evaluated for selected population groups (men and women). Excess mortality (number of deaths) and morbidity (number of hospital admissions) were determined as differences between observed and expected daily values, the latter being adjusted for long-term changes, annual and weekly cycles, and epidemics of influenza/acute respiratory infections. Generally higher relative excess CVD mortality on warm days than on cold days was identified in both regions. In contrast to mortality, weak excess CVD morbidity was observed for both warm and cold days. Different responses of individual CVDs to heat versus cold stress may be caused by the different nature of each CVD and different physiological processes induced by heat or cold stress. The slight differences between Prague and southern Bohemia in response to heat versus cold stress suggest the possible influence of environmental and socioeconomic factors such as the effects of urban heat island and exposure to air pollution, lifestyle differences, and divergence in population structure, which may result in differing vulnerability of urban versus rural population to temperature extremes. [ABSTRACT FROM AUTHOR]

The Murray dairy region produces approximately 1.85 billion litres of milk each year, representing about 20 % of Australia's total annual milk production. An ongoing production challenge in this region is the management of the impacts of heat stress during spring and summer. An increase in the frequency and severity of extreme temperature events due to climate change may result in additional heat stress and production losses. This paper assesses the changing nature of heat stress now, and into the future, using historical data and climate change projections for the region using the temperature humidity index (THI). Projected temperature and relative humidity changes from two global climate models (GCMs), CSIRO MK3.5 and CCR-MIROC-H, have been used to calculate THI values for 2025 and 2050, and summarized as mean occurrence of, and mean length of consecutive high heat stress periods. The future climate scenarios explored show that by 2025 an additional 12-15 days (compared to 1971 to 2000 baseline data) of moderate to severe heat stress are likely across much of the study region. By 2050, larger increases in severity and occurrence of heat stress are likely (i.e. an additional 31-42 moderate to severe heat stress days compared with baseline data). This increasing trend will have a negative impact on milk production among dairy cattle in the region. The results from this study provide useful insights on the trends in THI in the region. Dairy farmers and the dairy industry could use these results to devise and prioritise adaptation options to deal with projected increases in heat stress frequency and severity. [ABSTRACT FROM AUTHOR]

The aim of this paper was to evaluate the effects of three different feeding management (FM) schedules on physiological markers of heat stress (HS), metabolic conditions, milk yield and quality during the hot season in dairy cows. The study involved 27 mid-lactating cows, subdivided in three homogeneous groups differing in feeding time and frequency: total mixed ration (TMR) delivered once daily in the morning (M); twice daily, half in the morning and half in the evening (ME); once daily in the evening (E). During the trial, blood samples were collected in the morning (a.m.) and in the evening (p.m.), breathing rate (BR), rectal temperature (RT), and milk yield were recorded and individual milk samples were collected. Microclimate data indicated that cows were subjected to mild-moderate HS. During the hotter days, cows receiving M treatment showed higher values of RT (38.97 °C vs 38.68 °C and 38.62 °C, in ME and E) and BR (71.44 vs 66.52 and 65.26 breaths min, in ME and E), a.m. plasma glucose was lower in M (3.69 vs 3.83 and 3.83 mmol L, in ME and E) and a.m. plasma urea was lower in E (4.82 vs 5.48 and 5.35 mmol L, in M and ME). Milk yield was unaffected by FM, as well as milk composition and cheese-making properties. Only milk protein content and yield were higher in M (3.42 vs 3.36 and 3.27 g 100 mL; and 1.11 vs 1.08 and 1.02 kg day, for ME and E). Our results on cow physiology indicate that M seems a less suitable FM to match cow welfare during the summer season. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to implement current and novel research techniques in human energy budget estimations to give more accurate and efficient application of models by a variety of users. Using the COMFA model, the conditioning level of an individual is incorporated into overall energy budget predictions, giving more realistic estimations of the metabolism experienced at various fitness levels. Through the use of VO reserve estimates, errors are found when an elite athlete is modelled as an unconditioned or a conditioned individual, giving budgets underpredicted significantly by −173 and −123 W m, respectively. Such underprediction can result in critical errors regarding heat stress, particularly in highly motivated individuals; thus this revision is critical for athletic individuals. A further improvement in the COMFA model involves improved adaptation of clothing insulation ( I), as well clothing non-uniformity, with changing air temperature ( T) and metabolic activity ( M). Equivalent T values (for I estimation) are calculated in order to lower the I value with increasing M at equal T. Furthermore, threshold T values are calculated to predict the point at which an individual will change from a uniform I to a segmented I (full ensemble to shorts and a T-shirt). Lastly, improved relative velocity ( v) estimates were found with a refined equation accounting for the degree angle of wind to body movement. Differences between the original and improved v equations increased with higher wind and activity speeds, and as the wind to body angle moved away from 90°. Under moderate microclimate conditions, and wind from behind a person, the convective heat loss and skin temperature estimates were 47 W m and 1.7°C higher when using the improved v equation. These model revisions improve the applicability and usability of the COMFA energy budget model for subjects performing physical activity in outdoor environments. Application is possible for other similar energy budget models, and within various urban and rural environments. [ABSTRACT FROM AUTHOR]

The aim of this work is to study heat waves (HWs) in Mexicali, Mexico, because numerous deaths have been reported in this city, caused by heatstroke. This research acquires relevancy because several studies have projected that the health impacts of HWs could increase under various climate change scenarios, especially in countries with low adaptive capacity, as is our case. This paper has three objectives: first, to analyze the observed change in the summer (1 June to 15 September) daily maximum temperature during the period from 1951 to 2006; secondly, to characterize the annual and monthly evolution of frequency, duration and intensity of HWs; and finally, to generate scenarios of heat days (HDs) by means of a statistical downscaling model, in combination with a global climate model (HadCM3), for the 2020s, 2050s, and 2080s. The results show summer maximum temperatures featured warming and cooling periods from 1951 until the mid-1980s and, later, a rising tendency, which prevailed until 2006. The duration and intensity of HWs have increased for all summer months, which is an indicator of the severity of the problem; in fact, there are 2.3 times more HWs now than in the decade of the 1970s. The most appropriate distribution for modeling the occurrence of HDs was the Weibull, with the maximum temperature as co-variable. For the 2020s, 2050s, and 2080s, HDs under a medium-high emissions scenario (A2) could increase relative to 1961–1990, by 2.1, 3.6, and 5.1 times, respectively, whereas under a medium-low emissions scenario (B2), HDs could increase by 2.4, 3.4, and 4.0, for the same projections of time. [ABSTRACT FROM AUTHOR]

Abstract  The present paper describes a physical model that estimates the globe and the natural wet bulb temperatures from the main parameters generally recorded at meteorological weather stations, in order to predict the wet bulb globe temperature (WBGT) heat stress index for outdoor environments. The model is supported by a thermal analysis of the globe and the natural wet bulb temperature sensors. The results of simultaneous measurements of the WBGT and climatological parameters (solar radiation, wind velocity, humidity, etc.) are presented and used to validate the model. The final comparison between calculated and measured values shows a good agreement with the experimental data, with a maximum absolute deviation of 2.8% for the globe temperature and 2.6% for the natural wet bulb temperature and the WBGT index. The model is applied to the design reference year for Coimbra, Portugal, in order to illustrate its preventative capabilities from a practical point of view. The results clearly show that during the summer there is a critical daily period (1200–1600 hours, local standard time) during which people working outdoors should not be allowed to perform their normal activities. [ABSTRACT FROM AUTHOR]

The Tromp Award is the highest honor awarded by the International Society of Biometeorology (ISB). The award acknowledges outstanding research in biometeorology by a scientist under the age of 35 and was established in conjunction with the Tromp Foundation and the ISB. In honor of the 60th anniversary of the ISB, this article will provide a brief summary of the life of Dr. Solco Tromp and of the six awardees of the Tromp Award since the inaugural issuance of the award in 1999. The Tromp Award was established in part to recognize and support the efforts of young biometeorological professionals. As the brief summary of the awardees and a few of their selected subsequent publications have shown, the ISB and the Tromp Award has proven effective at identifying and supporting promising young scientists. [ABSTRACT FROM AUTHOR]

It is well documented that heat-stress burdens sheep welfare and productivity. Peak heat-stress levels are observed when high temperatures prevail, i.e. during heat waves; however, continuous measurements inside livestock buildings are not usually available for long periods so as to study the variation of summer heat-stress levels for several years, especially during extreme hot weather. Α methodology to develop a long time series of summer temperature and relative humidity inside naturally ventilated sheep barns is proposed. The accuracy and the transferability of the developed linear regression models were verified. Temperature Humidity Index (THI) was used to assess sheep's potential heat-stress. Τhe variation of THI inside a barn during heat wave and non-heat wave days was examined, and the results were comparatively assessed. The analysis showed that sheep were exposed to moderate, severe, and extreme severe heat-stress in 10, 21 and 66 % of hours, respectively, during heat wave days, while the corresponding values during non-heat wave days were 14, 33 and 43 %, respectively. The heat load on sheep was much higher during heat wave events than during non-heat wave periods. Additionally, based on the averaged diurnal variation of THI, it was concluded that extreme severe heat-stress conditions were prevailing between 1000 and 2400 hours local time during heat wave days. Cool off night periods were never and extremely rarely detected during heat wave and non-heat wave days, respectively. [ABSTRACT FROM AUTHOR]

Courtyards have been used over many centuries as an interesting architectural feature that extends the living area, with good opportunities for relaxation, contemplation, and also for social interactions in such interface with the outdoor environment. Those areas can also act as climate modifiers and have tempering effects in hot regions. Depending on their geometrical features, courtyards can promote excellent shading and natural ventilation opportunities in tropical regions. This study is focused on the evaluation of two historic courtyards with very distinct solar exposure in a city located in a tropical savannah climate. Field monitoring was carried out alongside surveys with visitors to the courtyards. Results showed the potential of both courtyards in reducing the level of heat stress during peak daytime hours with their climate tempering function. The deeper courtyard yielded steadier cooling effect during daytime than the shallower one. Heat stress, here interpreted in terms of the universal thermal climate index (UTCI) was also more reduced in the deep courtyard. For the subjective part, there was a larger fluctuation of thermal sensation votes for a low level of heat stress in the shallower courtyard but less so and even an opposite pattern for higher heat stress. In essence, the geometric shape of the evaluated courtyards was considered to be paramount to provide thermal attenuation to their visitors due to the interplay between shading and solar access, even though the effect was not observed in their TS votes for increasing heat stress. [ABSTRACT FROM AUTHOR]

Profitable production of rabbit meat requires comfortable environment for expression of good quality traits embedded in the genetic components of rabbits. One of the major problems facing rabbit production is heat stress, especially in hot regions of the world. This is further aggravated by global warming being experienced as a result of climate change. Rabbits have no or few sweat glands, complicating the problem of heat dissipation, thereby predisposing the animals to heat stress (HS). Heat stress adversely affect welfare and adaptation, feed consumption and utilization, immunity and health status, growth, reproduction, and milk production in rabbits. Rabbits are homoeothermic animals. They should be capable of body temperature regulation within a narrow range. Thermoregulation is extremely poor in rabbits because of lack of sweat glands. Rabbits are highly sensitive to high ambient temperature. The presence of thick insulator fur on the skin further impedes heat loss in rabbits. This review summarizes data available literatures in the last two decades (2000–2020). Short compilation on management techniques adopted in rearing rabbits under hot conditions is included. [ABSTRACT FROM AUTHOR]

Changes in frequency and severity of heat waves due to climate change pose a considerable challenge to livestock production systems. Although it is well known that heat stress reduces feed intake in cattle, effects of heat stress vary between animal genotypes and climatic conditions and are context specific. To derive a generic global prediction that accounts for the effects of heat stress across genotypes, management and environments, we conducted a systematic literature review and a meta-analysis to assess the relationship between dry matter intake (DMI) and the temperature-humidity index (THI), two reliable variables for the measurement of feed intake and heat stress in cattle, respectively. We analysed this relationship accounting for covariation in countries, breeds, lactation stage and parity, as well as the efficacy of various physical cooling interventions. Our findings show a significant negative correlation (r = − 0.82) between THI and DMI, with DMI reduced by 0.45 kg/day for every unit increase in THI. Although differences in the DMI-THI relationship between lactating and non-lactating cows were not significant, effects of THI on DMI varied between lactation stages. Physical cooling interventions (e.g. provision of animal shade or shelter) significantly alleviated heat stress and became increasingly important after THI 68, suggesting that this THI value could be viewed as a threshold for which cooling should be provided. Passive cooling (shading) was more effective at alleviating heat stress compared with active cooling interventions (sprinklers). Our results provide a high-level global equation for THI-DMI across studies, allowing next-users to predict effects of heat stress across environments and animal genotypes. [ABSTRACT FROM AUTHOR]

Globally, the poultry industry is gaining significant importance among the agricultural and its allied sectors. However, heat stress was found to negatively affect the poultry production particularly in the tropical regions. This review is therefore an attempt to generate information pertaining to the impacts of heat stress on poultry production and its amelioration. Heat stress reduces the growth, reproductive performance, and egg production in poultry birds. The reduction in productive potential of poultry birds on exposure to heat stress may be attributed to the deviation of energy resources from production to adaptation pathway. There are different approaches pertaining to relieving the adverse impacts of heat stress on poultry production. These approaches can be broadly categorized under genetic, management, and nutritional strategies. These approaches may reduce the negative effects of heat stress and enhance the productive performance of poultry birds. The management strategies include appropriate shelter design, providing shade, using sprinklers, implementing cooling devices, and using fans and ventilation systems. The recommended floor space for mature birds weighing 1.7 kg is 0.06 m2/bird while it is 0.13 m2/bird for the birds weighing 3.5 kg with 27.8 kg/m2 bird density in either case. The nutritional interventions comprise ration balancing and providing essential micronutrients to improve the productive and reproductive performance in poultry birds. Fat, antioxidants, yeast, and electrolyte supplementations are some of the most commonly used nutritional strategies to ensure optimum production in the poultry industry. Furthermore, providing adequate water supply and disease surveillance measures may help to ensure optimum meat and egg production in the birds. The advanced biotechnological tools may aid to identify suitable genetic markers in poultry birds which might help in developing new strains of higher thermo-tolerance by designing suitable breeding program involving marker-assisted selection. These strategies may help to optimize and sustain poultry production in the changing climate scenario. [ABSTRACT FROM AUTHOR]

Heat shock proteins (Hsp) aid in protein folding and also to combat stress in all cellular organisms. HspB1 is a member of the small HSP family that has a significant role in thermo-tolerance. In this study, we aimed to determine the relationship (if any) between age at sexual maturity of layer poultry (Rhode Island Red and Punjab Red) and HspB1 expression both at mRNA and protein levels under heat stress. The mRNA expression of hspB1 was checked by real-time PCR. Delay in sexual maturity of the birds was found to be directly associated with the hspB1 mRNA expression in both the bird varieties under heat stress. No significant regression (association) of hspB1 mRNA expression with age at sexual maturity was observed in case of control, non-heat stressed birds. The serum levels of HspB1 were measured by indirect ELISA, using recombinant HspB1 that was expressed using pET-32b(+) vector in BL21(DE3) cells. Serum HspB1 concentration increased significantly (p ≤ 0.001) in heat-stressed birds as compared with control ones. A significant association was found between the increase in serum HspB1 concentration and delay in sexual maturity of all the birds under heat stress while no such association was found in control birds. In conclusion, HspB1 mRNA and protein expression were found to be associated with age at sexual maturity in Punjab Red and RIR layers under heat stress. [ABSTRACT FROM AUTHOR]

Global warming seems more probable, whether as gradual warming or increased frequency of warmer episodes. The productivity of cattle in temperate countries will decline unless counteracting steps are adopted. The probability of pre-emptive breeding for maintaining temperate breed performance coupled with heat stress tolerance is too low to be adopted for counteracting warming. The expected warming will mostly involve temperature increases. These will indirectly affect radiant heat gain in animals owing to reduced radiant heat dissipation from the body by convective heat loss, which results in an increased sensitivity to incoming radiant heat at higher air temperatures. These necessitate an emphasis on increasing convective heat loss by structure design and forced air flow by fans. Convective heat loss diminishes with increasing air temperatures. Evaporative heat loss remains the alternative. Evaporative cooling of the ambient requires partial enclosing of the space surrounding the animals and is limited by the humidity in ambient air. An alternative was developed of coupling forced ventilation with wetting of animal surface. The exchange of ambient air flowing on animal surface makes the evaporation practically independent of air humidity and the loss of heat from animal surface practically independent of the surface to air temperature gradient. The coupling of forced ventilation with wetting combination may be attained in various parts of the dairy farm, the holding area of the milking parlour, the feeding trip and the resting area. Each of these requires differing structural and technological adaptations. Climate and farming systems vary between locations which require specific solutions. [ABSTRACT FROM AUTHOR]

Exertional heat illness (EHI) risk is a serious concern among athletes, laborers, and warfighters. US Governing organizations have established various activity modification guidelines (AMGs) and other risk mitigation plans to help ensure the health and safety of their workers. The extent of metabolic heat production and heat gain that ensue from their work are the core reasons for EHI in the aforementioned population. Therefore, the major focus of AMGs in all settings is to modulate the work intensity and duration with additional modification in adjustable extrinsic risk factors (e.g., clothing, equipment) and intrinsic risk factors (e.g., heat acclimatization, fitness, hydration status). Future studies should continue to integrate more physiological (e.g., valid body fluid balance, internal body temperature) and biometeorological factors (e.g., cumulative heat stress) to the existing heat risk assessment models to reduce the assumptions and limitations in them. Future interagency collaboration to advance heat mitigation plans among physically active population is desired to maximize the existing resources and data to facilitate advancement in AMGs for environmental heat. [ABSTRACT FROM AUTHOR]

This study quantifies heat-stress hazard (air temperature), vulnerability (heat vulnerability index and age score), and risk (heat-related mortality) on the district scale in Seoul, Korea, for a comprehensive heat-stress impact assessment. Moreover, the heat-stress impact assessment is evaluated by checking the spatial consistency between heat-stress hazard, vulnerability, and risk, which was rarely done before. We applied numerical and geo-empirical models to simulate the spatial pattern of heat-stress hazard. For heat-stress vulnerability, we used demographic and socioeconomic factors. Heat-related mortality was estimated based on an event-based heat-stress risk analysis. Results are that heat-stress hazard, vulnerability, and risk are spatially variable in Seoul. The highest heat-stress hazard was detected in the districts Mapo, Yeongdeungpo, and Yangcheon, the highest vulnerability in Jongno and the highest risk in Jongno and Yangcheon. The different components (heat-stress hazard, vulnerability, and risk) and variables (heat vulnerability index and percentage of seniors) showed different spatial patterns. Knowledge about the causes of higher heat-stress risk, either the hazard or vulnerability, is helpful to design tailored adaptation measures that focus on the reduction of thermal loads or on the preparation of the vulnerable population. The evaluation showed that heat-stress vulnerability and hazard explain the spatial pattern of risk only partly. This highlights the need to evaluate heat-stress impact assessment systems to produce reliable urban heat-stress maps. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effectiveness and practicality of a cooling intervention with a newly designed cooling vest on heat strain attenuation in the construction industry. Fourteen construction workers volunteered to participate in the field study. Each participant took part in two trials, i.e., cooling and control. Construction work included morning and afternoon sessions. Cooling intervention was implemented for 15 and 30 min during the morning and afternoon rest periods, respectively, between repeated bouts of work. Micrometeorological (wet-bulb globe temperature [WBGT]), physiological (tympanic temperature and heart rate), and perceptual (ratings of perceived exertion [RPE] and thermal sensation) measurements were taken during the test. Heat strain indices, including physiological strain index (PSIHR) and perceptual strain index (PeSI), were estimated accordingly. During the study, construction workers were exposed to a hot environment with a mean WBGT of 31.56 ± 1.87 °C. Compared with the control, physiological and perceptual strain were significantly reduced in the cooling condition during rest and subsequent work periods (p < 0.05; d = 0.24-1.07, small to large cooling effect). Cooling intervention significantly alleviates heat strain in the construction industry. The effectiveness and practicality of a proposed cooling intervention were tested in a field study. Results provide a reference for setting guidelines and promoting application on a range of construction sites. [ABSTRACT FROM AUTHOR]

In this work, the potential of the Universal Thermal Climate Index (UTCI) as a heat-related health risk indicator in Europe is demonstrated. The UTCI is a bioclimate index that uses a multi-node human heat balance model to represent the heat stress induced by meteorological conditions to the human body. Using 38 years of meteorological reanalysis data, UTCI maps were computed to assess the thermal bioclimate of Europe for the summer season. Patterns of heat stress conditions and non-thermal stress regions are identified across Europe. An increase in heat stress up to 1 °C is observed during recent decades. Correlation with mortality data from 17 European countries revealed that the relationship between the UTCI and death counts depends on the bioclimate of the country, and death counts increase in conditions of moderate and strong stress, i.e., when UTCI is above 26 and 32 °C. The UTCI’s ability to represent mortality patterns is demonstrated for the 2003 European heatwave. These findings confirm the importance of UTCI as a bioclimatic index that is able to both capture the thermal bioclimatic variability of Europe, and relate such variability with the effects it has on human health. [ABSTRACT FROM AUTHOR]

Under temperate climates, cattle are often at pasture in summer and are not necessarily provided with shade. We aimed at evaluating in a temperate region (Belgium) to what extent cattle may suffer from heat stress (measured through body temperature, respiration rate and panting score, cortisol or its metabolites in milk, and feces on hot days) and at assessing the potential benefits of shade. During the summer of 2012, 20 cows were kept on pasture without access to shade. During the summer of 2011, ten cows had access to shade (young trees with shade cloth hung between them), whereas ten cows had no access. Climatic conditions were quantified by the Heat Load Index (HLI). In animals without access to shade respiration rates, panting scores, rectal temperatures, and milk cortisol concentrations increased as HLI increased in both 2011 and 2012. Fecal cortisol metabolites varied with HLI in 2011 only. When cattle had access to shade, their use of shade increased as the HLI increased. This effect was more pronounced during the last part of the summer, possibly due to better acquaintance with the shade construction. In this case, shade use increased to 65% at the highest HLI (79). Shade tempered the effects on respiration, rectal temperature, and fecal cortisol metabolites. Milk cortisol was not influenced by HLI for cows using shade for > 10% of the day. Therefore, even in temperate areas, cattle may suffer from heat when they are at pasture in summer and providing shade can reduce such stress. [ABSTRACT FROM AUTHOR]

The aims of this study are to explore the “offensive” summer weather types classified under the spatial synoptic classification (SSC) system and to evaluate their impacts on excess mortality in 14 Korean cities. All-cause deaths per day for the entire population were examined over the summer months (May-September) of 1991-2010. Daily deaths were standardized to account for long-term trends of subcycles (annual, seasonal, and weekly) at the mid-latitudes. In addition, a mortality prediction model was constructed through multiple stepwise regression to develop a heat-health warning system based on synoptic climatology. The result showed that dry tropical (DT) days during early summer caused excess mortality due to non-acclimatization by inhabitants, and moist tropical (MT) plus and double plus resulted in greater spikes of excess mortality due to extremely hot and humid conditions. Among the 14 Korean cities, highly excess mortality for the elderly was observed in Incheon (23.2%, 95%CI 5.6), Seoul (15.8%, 95%CI 2.6), and Jeonju (15.8%, 95%CI 4.6). No time lag effect was observed, and excess mortality gradually increased with time and hot weather simultaneously. The model showed weak performance as its predictions were underestimated for the validation period (2011-2015). Nevertheless, the results clearly revealed the efficiency of relative and multiple-variable approaches better than absolute and single-variable approaches. The results indicate the potential of the SSC as a suitable system for investigating heat vulnerability in South Korea, where hot summers could be a significant risk factor. [ABSTRACT FROM AUTHOR]

With a view to occupational effects of climate change, we performed a simulation study on the influence of different heat stress assessment metrics on estimated workability (WA) of labour in warm outdoor environments. Whole-day shifts with varying workloads were simulated using as input meteorological records for the hottest month from four cities with prevailing hot (Dallas, New Delhi) or warm-humid conditions (Managua, Osaka), respectively. In addition, we considered the effects of adaptive strategies like shielding against solar radiation and different work-rest schedules assuming an acclimated person wearing light work clothes (0.6 clo). We assessed WA according to Wet Bulb Globe Temperature (WBGT) by means of an empirical relation of worker performance from field studies (Hothaps), and as allowed work hours using safety threshold limits proposed by the corresponding standards. Using the physiological models Predicted Heat Strain (PHS) and Universal Thermal Climate Index (UTCI)-Fiala, we calculated WA as the percentage of working hours with body core temperature and cumulated sweat loss below standard limits (38 °C and 7.5% of body weight, respectively) recommended by ISO 7933 and below conservative (38 °C; 3%) and liberal (38.2 °C; 7.5%) limits in comparison. ANOVA results showed that the different metrics, workload, time of day and climate type determined the largest part of WA variance. WBGT-based metrics were highly correlated and indicated slightly more constrained WA for moderate workload, but were less restrictive with high workload and for afternoon work hours compared to PHS and UTCI-Fiala. Though PHS showed unrealistic dynamic responses to rest from work compared to UTCI-Fiala, differences in WA assessed by the physiological models largely depended on the applied limit criteria. In conclusion, our study showed that the choice of the heat stress assessment metric impacts notably on the estimated WA. Whereas PHS and UTCI-Fiala can account for cumulative physiological strain imposed by extended work hours when working heavily under high heat stress, the current WBGT standards do not include this. Advanced thermophysiological models might help developing alternatives, where not only modelling details but also the choice of physiological limit criteria will require attention. There is also an urgent need for suitable empirical data relating workplace heat exposure to workability. [ABSTRACT FROM AUTHOR]

Breed, age, coat colour, month and temperature humidity index (THI) influence on body weight (W), body condition score (BCS), thermophysiological variables (rectal temperature (Tr), skin temperature (Tsk)) and hair length was studied in Nguni ( n = 19) and Boran ( n = 16). As a result of this study, breed influenced W, BCS and Tsk on the neck and belly ( P < 0.05). The BCS and W of Nguni cows were higher than the Boran cows. Hair length of both breeds increased from February to August. The THI influenced thermophysiological variables ( P < 0.05). Increased Tr for both breeds was recorded in February and April, respectively ( P < 0.05). Month influenced Tsk and June recorded lower values ( P < 0.05). Younger cows (3-8 years) had lower weight and high Tr and Tsk ( P < 0.05). Nguni cows had high neck and thurl temperatures in June while Boran cows had the highest in August ( P < 0.05). Red, dun and white-black Boran cows had increased BCS. Nguni cows with red, fawn and white cows had high BCS. Fawn-coloured Nguni cows and white-brown Boran cows had the more weight than cows with other colours compared in the study. White-red Nguni and Boran cows recorded the highest Tr. For Nguni cows, neck and belly temperatures were significantly ( P < 0.001) correlated to thurl temperature. Boran cows had significant ( P < 0.001) correlations for THI and neck, belly and thurl temperatures. The current study found that Nguni cows were more adapted to the prevailing bioclimatic changes. However, Boran cows have the potential of performing well under heat stress conditions over time. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of heat stress (HS) on digestibility of protein and fat and the expression of nutrient transporters in broilers. Forty-eight male Cobb500 chicks were used in this study. At day 14, birds were randomly divided into two groups and kept under either constant normal temperature (25 °C) or high temperature (35 °C) in individual cages. Five birds per treatment at 1 and 12 days post-treatment were euthanized, and Pectoralis major ( P. major) and ileum were sampled for gene expression analysis. At day 33, ileal contents were collected and used for digestibility analysis. The total consumption and retention of protein and fat were significantly lower in the HS group compared to the control group. Meanwhile, the retention of crude protein per BWG was significantly higher in the HS group compared to the control group. In P. major and ileum tissues at day 1, transporters FATP1 and SGLT1 were down-regulated in the HS group. Meanwhile, FABP1 and PepT1 were down-regulated only in the ileum of the HS group. The converse was shown in P. major. The nutrient transporter FABP1 at day 12 post-HS was down-regulated in the P. major and ileum, but GLUT1 and PepT2 were down-regulated only in the ileum, and PepT1 was down-regulated only in the P. major compared with the control group. These changes in nutrient transporters suggest that high ambient temperature might change the ileum and P. major lipids, glucose, and oligopeptide transporters. [ABSTRACT FROM AUTHOR]

The aim of the present study was to examine the effects of non-genetic factors on scrotal thermographic profile viz., proximal pole temperature (PPT °C), mid pole temperature (MPT °C), distal pole temperature (DPT °C) and ocular temperature (OcT) of Murrah ( Bubalus bubalis) breeding bulls. A total of 109 buffalo bulls, maintained at three semen stations (SS), were monitored for scrotal surface and ocular temperatures using infrared thermography twice daily during rainy, winter and summer seasons using an FLIR i5 infrared camera and temperatures were measured. Thermograms were analysed by FLIR QuickReport v.1.2 SP2 software. Statistical analysis revealed that semen station, season, temperature humidity index (THI), housing system and timing of observations had significant ( P < 0.05) effect on scrotal surface temperature (SST) and OcT. In SS-I, the PPT and MPT were significantly ( P < 0.05) higher as compared to SS-II and SS-III. THI had significant ( P < 0.05) effect on SST and OcT, whereas PPT (°C), MPT (°C), DPT (°C) and OcT (°C) values during high THI (>80.88; <0.05) period were higher as compared to medium THI period (70.06-80.88) and during low THI period (<70.06). Temperature gradient (TG) of the testes was significantly ( P < 0.05) higher during low THI period (4.50 ± 0.06 °C) as compared to medium THI (2.38 ± 0.03 °C) and high THI (1.61 ± 0.05 °C). Season of the year had a significant effect ( P < 0.05) on the SST and OcT. During the rainy season, PPT (34.50 ± 0.09 °C), MPT (33.44 ± 0.12 °C) and DPT (32.11 ± 0.15 °C) were significantly ( P < 0.05) higher as compared to winter and summer seasons. Age of the bulls had non-significant effect on SST and OcT but had a marked influence on thermal profile of scrotum. It could be concluded semen station, season, temperature humidity index, housing system and timing of observations had a significant influence on scrotal surface temperature. The monitoring of scrotal surface temperature by infrared thermography was found to be useful in evaluating the effects of thermal stress on physiology and health of buffalo bulls. [ABSTRACT FROM AUTHOR]

Heat-related effects on mortality have been widely analyzed using maximum and minimum temperatures as exposure variables. Nevertheless, the main focus is usually on the former with the minimum temperature being limited in use as far as human health effects are concerned. Therefore, new thermal indices were used in this research to describe the duration of night hours with air temperatures higher than the 95% percentile of the minimum temperature (hot night hours) and intensity as the summation of these air temperatures in degrees (hot night degrees). An exposure-response relationship between mortality due to natural, respiratory, and cardiovascular causes and summer night temperatures was assessed using data from the Barcelona region between 2003 and 2013. The non-linear relationship between the exposure and response variables was modeled using a distributed lag non-linear model. The estimated associations for both exposure variables and mortality shows a relationship with high and medium values that persist significantly up to a lag of 1-2 days. In mortality due to natural causes, an increase of 1.1% per 10% (CI95% 0.6-1.5) for hot night hours and 5.8% per each 10° (CI95% 3.5-8.2%) for hot night degrees is observed. The effects of hot night hours reach their maximum with 100% and lead to an increase by 9.2% (CI95% 5.3-13.1%). The hourly description of night heat effects reduced to a single indicator in duration and intensity is a new approach and shows a different perspective and significant heat-related effects on human health. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the whole-blood levels of miR-155, miR-223, miR-181a, miR-146a, and miR-let-7e in patients with bilateral knee osteoarthritis (OA) after a cycle of mud-bath therapy (MBT). Thirty-two patients with knee OA defined by the ACR criteria were included. Twenty-one patients (MBT group) were daily treated with a combination of local mud-packs at 42 °C and baths in mineral water, at 37 °C for 15 min, for 12 applications over a period of 2 weeks, in addition to standard therapy; 11 patients (control group) continued their conventional treatment alone. Global pain score evaluated by visual analog scale (VAS), WOMAC subscores, and microRNA expression were evaluated at baseline and after 2 weeks. Peripheral whole blood was collected into PAXgene™ Blood RNA tubes, stored at − 80 °C, and total RNA was extracted. The expression of miR-155, miR-223, miR-181a, miR-146a, and miR-let-7e was determined by qRT-PCR. After MBT, we observed a statistically significant improvement of clinical parameters and a significant decrease of miR-155, miR-181a, miR-146a ( p < 0.001), and miR-223 ( p < 0.01) expression levels. No clinical and biochemical modifications were detected in the control group. No significant variations of miR-let-7e were shown in both groups after 2 weeks. In conclusion, MBT can modify the expression of miR-155, miR-181a, miR-146a, and miR-223, which are upregulated in OA. It could be due to the heat stress and the hydrostatic pressure, since some miRNAs were found to be temperature- and mechano-responsive. Further studies are needed to better explain the mechanism of action of MBT and the role of miRNAs in OA. [ABSTRACT FROM AUTHOR]

Increasing temperatures associated with global climate change threaten to disrupt agricultural systems such as beef production, yet relatively little is known about the use of natural tree shade to mitigate the negative effects of heat stress on beef cattle. In this study, we evaluated how temperature and time of day influenced the utilization of tree shade in relation to coloration, orientation, and behavior of beef cattle in a pasture system. Temperatures in shade and direct sunlight were measured using black globe temperature (BGT) data loggers. Time-lapse images from game cameras were used to obtain counts of shade usage, coloration, orientation, and behavior of cattle throughout the daytime hours. In general, we found that shade utilization and most of the predominating orientations and behaviors differed significantly ( P < 0.05) by both time of day (Hour) and BGT in direct sunlight (BGT), while interactions between these two effects (Hour × BGT) were often nonsignificant. The mean percentage of the herd using shade was highest in mid-morning (87-96%) and early afternoon (97%), but also increased with BGT regardless of the time of day; these trends were similar for both dark- and light-colored cattle. Lying down was the dominant behavior exhibited in the shade, while foraging was the most prevalent behavior in the sun. When herd shade usage was lowest in mid- to late-afternoon (<1%) we also observed an increase in the use of heat-mitigating orientations in the sun (37-47%). We discuss some practical implications of these results, including the potential use of temperature thresholds to interpret cattle behaviors and shade usage. [ABSTRACT FROM AUTHOR]

Thermal effects of the environment are the most prominent environmental influences on the human body. Keeping the body core temperature in a narrow optimum range is the dominating physiological process. Thus, assessing thermal environments has been a major field in biometeorology for many decades, which is also reflected in the number of respective articles and their citations. In the early days of thermal assessments, simple indices only considering a few environmental parameters were used. The next step has been the development of heat budget models describing all relevant heat/energy fluxes to and from the human body. One of the first was PET, which has been presented in the most cited IJBM publication ever (1999). All of these models created by individual scientists have some shortcomings and confinements in their application. In order to overcome such restrictions and to bring the state of the art scientists of thermal modelling together a working group to define a 'universal' thermal climate index (UTCI) has been founded, backed and driven by an own commission of the International Society of Biometeorology. This working group has developed a comprehensive open source tool to calculate UTCI for the assessment of outdoor thermal environments for biometeorological applications (see the IJBM special issue 56 (2012) on UTCI). [ABSTRACT FROM AUTHOR]

High ambient temperatures are a determining factor in the deterioration of embryo quality and survival in mammals. The aim of this study was to evaluate the effect of heat stress on embryo development, embryonic size and size of the embryonic coats in rabbits. A total of 310 embryos from 33 females in thermal comfort zone and 264 embryos of 28 females in heat stress conditions were used in the experiment. The traits studied were ovulation rate, percentage of total embryos, percentage of normal embryos, embryo area, zona pellucida thickness and mucin coat thickness. Traits were measured at 24 and 48 h post-coitum (hpc); mucin coat thickness was only measured at 48 hpc. The embryos were classified as zygotes or two-cell embryos at 24 hpc, and 16-cells or early morulae at 48 hpc. The ovulation rate was one oocyte lower in heat stress conditions than in thermal comfort. Percentage of normal embryos was lower in heat stress conditions at 24 hpc (17.2%) and 48 hpc (13.2%). No differences in percentage of zygotes or two-cell embryos were found at 24 hpc. The embryo development and area was affected by heat stress at 48 hpc (10% higher percentage of 16-cells and 883 μm smaller, respectively). Zona pellucida was thicker under thermal stress at 24 hpc (1.2 μm) and 48 hpc (1.5 μm). No differences in mucin coat thickness were found. In conclusion, heat stress appears to alter embryology in rabbits. [ABSTRACT FROM AUTHOR]

Heat stress induced by high ambient temperature is a major concern in commercial broiler production. To evaluate the effects of dietary enzymatically treated Artemisia annua L. (EA) supplementation on growth performance and liver oxidative injury of broilers reared under heat stress, a total of 320 22-day-old male broilers were randomly allotted into five groups with eight replicates of eight birds each. Broilers in the control group were housed at 22 ± 1 °C and fed the basal diet. Broilers in the HS, HS-EA1, HS-EA2, and HS-EA3 groups were fed basal diet supplemented with 0, 0.75, 1.00, and 1.25 g/kg EA, respectively, and reared under cyclic high temperature (34 ± 1 °C for 8 h/day and 22 ± 1 °C for 16 h/day). Broilers fed EA diets had higher final body weight, average daily body weight gain, and average daily feed intake, as well as liver concentration of reduced glutathione, activities of antioxidant enzymes, abilities to inhibit hydroxyl radical and superoxide radical (HS-EA2 and HS-EA3), and lower liver concentrations of reactive oxygen metabolites, malondialdehyde, and protein carbonyl (HS-EA1, HS-EA2, and HS-EA3) than HS group ( P < 0.05). EA treatment downregulated the mRNA levels of heat shock proteins 70 and 90, upregulated the mRNA levels of nuclear factor erythroid 2-related factor 2 (HS-EA1, HS-EA2, and HS-EA3) and heme oxygenase 1 (HS-EA2 and HS-EA3) in liver of heat-treated broilers ( P < 0.05). In conclusion, EA alleviated heat stress-induced growth depression and liver oxidative injury in broilers, possibly through improving the antioxidant capacity and regulating the pertinent mRNA expression. The appropriate inclusion level of EA in broiler diet is 1.00-1.25 g/kg. [ABSTRACT FROM AUTHOR]

In tropical and semitropical regions, raising broiler chickens out of their thermal comfort zone can cause an added economic loss in the poultry industry. The cause for the deleterious effects on immunity and growth performance of broilers under high environmental temperatures is still poorly understood. Therefore, the aim of the current investigation was to evaluate the effect of heat stress on leukocytes protein synthesis and immune function as a possible direct cause of low performance in broiler chickens under such condition. In this study, 300 one-day-old male broiler chicks (Cobb500™) were randomly assigned into 2 groups with 5 replicates of 30 chicks each. From 21 to 42 days of age, one group was exposed to non-stressed condition at 24 °C and 50% relative humidity (control group), while the other group was exposed to heat stress at 35 °C and 50% relative humidity (HS group). At 42 days of age, blood samples were collected from each group to evaluate stress indicators, immune function, and leukocytes protein synthesis. Production performance was also recorded. Noteworthy, protein synthesis in leukocytes was significantly ( P < 0.05) inhibited in HS group by 38% compared to control group. In contrast, the phosphorylation level on threonine 56 site (Thr) of eukaryotic elongation factor (eEF2), which indicates the suppression of protein translation process through altering the protein elongation phase, was significantly threefold higher in HS group than in control ( P < 0.05). In addition, an increase in stress indicators was markedly ( P < 0.05) presented in the HS birds by twofold increase in heterophil/lymphocyte (H/L) ratio and threefold increase in plasma corticosterone level compared to control. Furthermore, the immune function was significantly ( P < 0.05) suppressed in HS birds than control (0.99 vs. 1.88 mg/mL plasma IgG, 89.2 vs. 148.0 μg/mL plasma IgM, 4.80 vs. 7.20 antibody titer against SRBC, and 1.38 vs. 3.39 stimulation index of lymphocyte proliferation in HS vs. control group, respectively). Moreover, results on the broiler performance indicate that HS birds had a significant ( P < 0.05) lower body weight gain by 58%, lower feed consumption by 39%, higher conversion ratio by 27%, and higher mortality by more than three times, compared to control birds. In conclusion, our results demonstrate that the inhibition of leukocyte protein synthesis through increasing the level of eEF2 Thr phosphorylation may play a key role in the observed decrease in immune function and growth performance with the high mortality rate encountered in broiler chickens under heat stress environment. [ABSTRACT FROM AUTHOR]

The climatic conditions in Croatia are deteriorating which significantly increases the frequency of heat stress. This creates a need for an adequate dairy farming strategy. The impact of heat stress can be reduced in many ways, but the best long-term solution includes the genetic evaluation and selection for heat stress resistance. In order to create the basis for genetic evaluation, this research determined the variation in daily milk yield (DMY) and somatic cell count (SCC) as well as the differences in resistance to heat stress due to production level (high, low) and breed (Holstein, Simmental) of dairy cattle breed in Croatia. For statistical analysis, 1,070,554 test-day records from 70,135 Holsteins reared on 5679 farms and 1,300,683 test-day records from 86,013 Simmentals reared on 8827 farms in Croatia provided by the Croatian Agricultural Agency were used. The results of this research indicate that the high-producing cows are much more susceptible to heat stress than low-producing especially Holsteins. Also, the results of this research indicate that Simmental breed, in terms of daily milk production and somatic cell count, could be more resistant to heat stress than Holstein. The following research should determine whether Simmentals are genetically more appropriate for the challenges that are in store for the future milk production in this region. Furthermore, could an adequate production level be achieved with Simmentals by maintaining the heat resistance? [ABSTRACT FROM AUTHOR]

This study was undertaken to first quantify the effect of heat stress on milk yield and components of Tarentaise in comparison to Holstein cows. A dataset of 16,143 monthly individual records of production traits was collected for 435 Tarentaise and 543 Holstein cows from 21 farms in Tunisia (2009 to 2014). This dataset was merged with meteorological data from 5 public stations relative to the 21 farms. The temperature-humidity index (THI), calculated as a combination of ambient temperature and relative humidity, was used to characterize heat stress. When the THI increased from an average value of 53.7 in winter to 75.4 in summer, the Holstein and Tarentaise cows decreased their milk production by 0.93 and 0.15 kg/day, respectively. Milk fat, protein, and urea content decreased similarly in both breeds (−2.20 g/kg, −1.40 g/kg, and −14 mg/L, respectively), and the milk somatic cell count increased for Holstein cows (+352,000/mL) while decreased for Tarentaise cows (−160,000/mL). The second aim of this study was to describe the relationship between the variations of the milk yields between the summer and the winter (Δ milk yields) and some barn characteristics during the hot season. A survey carried out on 19 of the 21 previous farms permitted to conclude that the closed buildings led to a higher decrease in milk yield between the summer and winter than the open buildings (−1.13 vs. −0.27 kg/day). A metallic roof had a more negative impact on Δ milk yields than the other roof types (−1.04 vs. −0.15 kg/day). [ABSTRACT FROM AUTHOR]

On August 1, 2001, Korey Stringer, a Pro Bowl offensive tackle for the Minnesota Vikings, became the first and to date the only professional American football player to die from exertional heat stroke (EHS). The death helped raise awareness of the dangers of exertional heat illnesses in athletes and prompted the development of heat safety policies at the professional, collegiate, and interscholastic levels. Despite the public awareness of this death, no published study has examined in detail the circumstances surrounding Stringer's fatal EHS. Using the well-documented details of the case, our study shows that Stringer's fatal EHS was the result of a combination of physiological limitations, organizational and treatment failings, and extreme environmental conditions. The COMfort FormulA (COMFA) energy budget model was used to assess the relative importance of several extrinsic factors on Stringer's EHS, including weather conditions, clothing insulation, and activity levels. We found that Stringer's high-intensity training in relation to the oppressive environmental conditions was the most prominent factor in producing dangerous, uncompensable heat stress conditions and that the full football uniform played a smaller role in influencing Stringer's energy budget. The extreme energy budget levels that led to the fatal EHS would have been avoided according to our modeling through a combination of reduced intensity and lower clothing insulation. Finally, a long delay in providing medical treatment made the EHS fatal. These results highlight the importance of modern heat safety guidelines that provide controls on extrinsic factors, such as the adjustment of duration and intensity of training along with protective equipment modifications based on environmental conditions and the presence of an emergency action plan focused on rapid recognition and immediate on-site aggressive cooling of EHS cases. [ABSTRACT FROM AUTHOR]

Six male Tharparkar cattle aged 2-3 years were selected for the study. The animals were acclimatized in the psychrometric chamber at thermoneutral zone (TNZ) for 15 days and then exposed to 42 °C temperature up to 23 days followed by 12 days of recovery period. Physiological responses were estimated, and peripheral blood mononuclear cells (PBMCs) were isolated at TNZ on day 1, day 5, and day 12; after 6 h of heat stress exposure on day 16 to day 20, day 25, day 30, day 32, day 34, day 36, and day 38; and a recovery period on day 45 and day 50. The PBMCs were cultured to study the effect of thermal challenge on HSP70 messenger RNA (mRNA) expression pattern at different temperature-time combinations. The mRNA and protein expression of HSP70 in PBMCs along with serum extracellular HSP70 (eHSP70) was increased ( P < 0.05) and showed two peaks on day 17 and day 32 (2nd and 17th days of thermal challenge, respectively). The HSP70 mRNA expression was increased ( P < 0.05) in a temperature- and time-dependent manner in heat stress challenge treatment as compared to control in cultured PBMCs. HSP70 expression was found to be higher ( P < 0.05) after 10 days of heat exposure (corresponds to chronic heat stress) as compared to the first 5 days of heat stress (corresponds to short-term heat stress) and control period at TNZ. The present findings indicate that HSP70 is possibly involved in heat stress adaptive response in Tharparkar cattle and the biphasic expression pattern may be providing a second window of protection during chronic heat stress. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the use of cow activity and rumination time by precision livestock farming tools as early alert for heat stress (HS) detection. A total of 58 Italian Friesian cows were involved in this study during summer 2015. Based on the temperature humidity index (THI), two different conditions were compared on 16 primiparous and 11 multiparous, to be representative of three lactation phases: early (15-84 DIM), around peak (85-154 DIM), and plateau (155-224 DIM). A separate dataset for the assessment of the variance partition included all the cows in the herd from June 7 to July 16. The rumination time (RT2h, min/2 h) and activity index (AI2h, bouts/2 h) were summarized every 2-h interval. The raw data were used to calculate the following variables: total daily RT (RTt), daytime RT (RTd), nighttime RT (RTn), total daily AI (AIt), daytime AI (AId), and nighttime AI (AIn). Either AIt and AId increased, whereas RTt, RTd, and RTn decreased with higher THI in all the three phases. The highest decrease was recorded for RTd and ranged from 49 % (early) to 45 % (plateau). The contribution of the cow within lactation phase was above 60 % of the total variance for AI traits and a share from 33.9 % (for RTt) to 54.8 % (RTn) for RT traits. These observations must be extended to different feeding managements and different animal genetics to assess if different thresholds could be identified to set an early alert system for the farmer. [ABSTRACT FROM AUTHOR]

Electric fan use in extreme heat wave conditions has been thought to be disadvantageous because it might accelerate heat gain to the body via convection. However, it has been recently shown that fan use delays increases in heart rate even at high temperatures (42 °C) in young adults. We here assess the biophysical and physiological mechanisms underlying the apparently beneficial effects of fan use. Eight males (24 ± 3 y; 80.7 ± 11.7 kg; 2.0 ± 0.1 m) rested at either 36 °C or 42 °C, with (F) or without (NF) electric fan use (4.2 m/s) for 120 min while humidity increased every 7.5 min by 0.3 kPa from a baseline value of 1.6 kPa. Heart rate (HR), local sweat rate (LSR), cutaneous vascular conductance (CVC), core and mean skin temperatures, and the combined convective/radiative heat loss (C+R), evaporative heat balance requirements (E) and maximum evaporative potential (E) were assessed. C+R was greater with fan use at 36 °C (F 8 ± 6, NF 2 ± 2 W/m; P = 0.04) and more negative (greater dry heat gain) with fan use at 42 °C (F −78 ± 4, NF −27 ± 2 W/m; P < 0.01). Consequently, E was lower at 36 °C (F 38 ± 16, NF 45 ± 3 W/m; P = 0.04) and greater at 42 °C (F 125 ± 1, NF 74 ± 3 W/m; P < 0.01) with fan use. However, fan use resulted in a greater E at baseline humidity at both 36 °C (F 343 ± 10, NF 153 ± 5 W/m; P < 0.01) and 42 °C (F 376 ± 13, NF 161 ± 4 W/m; P < 0.01) and throughout the incremental increases in humidity. Within the humidity range that a rise in HR was prevented by fan use but not without a fan, LSR was higher in NF at both 36 °C ( P = 0.04) and 42 °C ( P = 0.05), and skin temperature was higher in NF at 42 °C ( P = 0.05), but no differences in CVC or core temperatures were observed (all P > 0.05). These results suggest that the delayed increase in heart rate with fan use during extreme heat and humidity is associated with improved evaporative efficiency. [ABSTRACT FROM AUTHOR]