Prevent Heat Stress Research Articles

Lowering rumen-degradable and rumen-undegradable protein improved amino acid metabolism and energy utilization in lactating dairy cows exposed to heat stress

The objective of this study was to evaluate the effects of reducing dietary rumen-degradable protein (RDP) and rumen-undegradable protein (RUP) on protein and energy metabolism in heat-stressed dairy cows. Eighteen primiparous and 30 multiparous mid-lactation Holstein cows were used in a completely randomized design arranged in a 2 × 2 factorial (n = 12/treatment). Cows were randomly assigned to 1 of 4 dietary treatments that included 2 levels of RDP (10 and 8%; D) and 2 levels of RUP (8 and 6%; U) of dry matter for 21 d as (1) 10D:8U, (2) 8D:8U, (3) 10D:6U, and (4) 8D:6U. Diets were isoenergetic and contained 50% forage and 50% concentrate (dry matter basis). Cows were housed in a freestall barn. Three weeks before start of treatments, all animals were fed the 10D:8U diet and received supplemental cooling to prevent heat stress. During the treatment period, cows experienced a daily increment in temperature-humidity index from 74 to 82 for 1000 to 2000 h. Blood samples were collected on d -1 and 21 of the treatment period to determine plasma concentrations of AA, glucose, insulin, fatty acids, and β-hydroxybutyrate. For primiparous cows, reducing from 10 to 8% RDP decreased insulin concentrations. For multiparous cows, we found significant RDP by RUP interactions for insulin, β-hydroxybutyrate, fatty acids, total essential AA, and 3-methylhistidine concentrations. Reducing from 10 to 8% RDP decreased insulin concentrations at 6% RUP, but concentrations did not change when reducing RDP at 8% RUP. Reducing from 10 to 8% RDP decreased β-hydroxybutyrate concentrations at 8% RUP, but concentrations did not change when reducing RDP at 6% RUP. Reducing from 10 to 8% RDP increased nonesterified fatty acid and total essential AA concentrations at 8% RUP, but concentrations did not change when reducing RDP at 6% RUP. Reducing from 8 to 6% RUP decreased 3-methylhistidine concentration at 8% RDP, but not at 10% RDP. Reducing from 8 to 6% RUP increased milk protein yield efficiency in primiparous and multiparous cows. These results indicate that reducing RDP and RUP lowers circulating insulin, which was associated with mobilization and utilization of fatty acids. Reduced RDP and RUP increases the use of AA to maintain milk protein synthesis and limit AA catabolism in cows exposed to warm climates.

Assessment of occupational exposure to heat stress and solar ultraviolet radiation among groundskeepers in an eastern North Carolina university setting

ABSTRACTGroundskeepers spend most of the year working outdoors, exposing them to heat and solar ultraviolet (UV) radiation and increasing their risk to related adverse health effects. Various studies on heat and UV exposures in different occupations have been published, but those on groundskeepers are rare. The purpose of this study was to assess the exposure to heat stress and solar UV radiation among groundskeepers in an eastern North Carolina university setting. Wet bulb globe temperature (WBGT) index using a heat stress monitor and UV effective irradiance (UVeff) index using a digital UV meter were recorded in various work areas three times a day (morning, noon, afternoon) and during three seasons (spring, summer, fall). Data analysis was conducted using descriptive statistics, analysis of variance (ANOVA), Tukey Honestly Significant Difference (HSD), and Pearson Correlation tests. The mean (±SD) WBGT index was the highest in the afternoon (25.4 ± 5.0°C), summer (27.8 ± 3.1°C), and July (29.0 ± 2.6°C); the mean UVeff index was the highest at noon, summer and June (0.0116 ± 0.0061, 0.0101 ± 0.0081, and 0.0114 ± 0.0089 mW/cm2, respectively). Differences in the mean WBGT and UVeff indices within the time periods of day, seasons and months were significant (P < 0.01). The overall correlation between WBGT and UV indices was moderate (r = 0.42, P < 0.01) but lack of correlation was found during different times of the day during the fall and summer seasons. The largest percentages of WBGT indices exceeding the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLVs) for different workloads were found in the afternoon (11.3–40.7%), summer (14.6–56%), and July (28.8–76.3%). The mean UVeff for noon (0.0116 mW/cm2) and afternoon (0.0100 mW/cm2) exceeded the TLV for 30-min exposure. This study shows that groundskeepers are potentially exposed to excessive heat stress and UV radiation, and are at risk to developing heat- and UV-related illnesses. The study findings will be beneficial in implementing recommended control measures to prevent heat stress and UV exposure among groundskeepers and other similar outdoor workers.

Should Workers Avoid Consumption of Chilled Fluids in a Hot and Humid Climate?

Despite provision of drinking water as the most common method of occupational heat stress prevention, there remains confusion in hydration messaging to workers. During work site interactions in a hot and humid climate, workers commonly report being informed to consume tepid fluids to accelerate rehydration. When questioned on the evidence supporting such advice, workers typically cite that fluid absorption is delayed by ingestion of chilled beverages. Presumably, delayed absorption would be a product of fluid delivery from the gut to the intestines, otherwise known as gastric emptying. Regulation of gastric emptying is multifactorial, with gastric volume and beverage energy density the primary factors. If gastric emptying is temperature dependent, the impact of cooling is modest in both magnitude and duration (≤ 5 minutes) due to the warming of fluids upon ingestion, particularly where workers have elevated core temperature. Given that chilled beverages are most preferred by workers, and result in greater consumption than warm fluids during and following physical activity, the resultant increased consumption of chilled fluids would promote gastric emptying through superior gastric volume. Hence, advising workers to avoid cool/cold fluids during rehydration appears to be a misinterpretation of the research. More appropriate messaging to workers would include the thermal benefits of cool/cold fluid consumption in hot and humid conditions, thereby promoting autonomy to trial chilled beverages and determine personal preference. In doing so, temperature-based palatability would be maximized and increase the likelihood of workers maintaining or restoring hydration status during and after their work shift.

Testicular thermoregulation, scrotal surface temperature patterns and semen quality of water buffalo bulls reared in a tropical climate.

This study evaluated the capacity of thermoregulation and its consequences on the scrotal surface temperature patterns and semen quality of buffalo bulls raised in a wet tropical climate. Eleven water buffaloes were evaluated in the rainiest, in the transitional and in the less rainy season. Air temperature and humidity were consistently high, but the animals did not show thermal stress in any season. The scrotal temperature gradient of buffalo bulls using infrared thermography was described, and three parallel and decreasing thermal bands were characterised. Sperm quality (n=176 ejaculates) was maintained in normal parameters over the periods. Pearson's coefficients showed that sperm volume and progressive motility were negatively correlated with ocular globe, epididymal tail and minimum scrotal temperatures (p<.01). Sperm membrane integrity was negatively influenced by increases in epididymal tail and minimum scrotal temperatures (p<.01). Ocular globe temperature also showed positive correlation with rectal, spermatic cord, and epididymal tail temperatures (p<.01). Therefore, even under high temperature and humidity, the thermoregulatory system was effective in preventing heat stress and the normality of scrotal surface temperatures, spermatogenesis and sperm maturation were maintained.

Enrolment of Schools Teachers in Heat Stress Management Plan Targeting Vulnerable Dubai Schooling Kids, An Exercise in Community Engagement, Empowerment and Mobilization

Background: Dubai has well recognized hot and humid weather during the period extended from May up to October (6) months out of each the year. Which put the entire population at the risk of exposure to heat stress when they are practicing outdoor activities during their routine work at their workplaces every day? Furthermore, the kids are most fragile segment of population borne to develop heat stress incidents if measures to avoid such exposure have not been put in place properly Objectives: To assess the capacity building module on heat stress among Dubai school’s teachers, to study assess the extent of trainee’s response to heat stress at their facilities. Methodology: Enrolment and follow up of trainee’s cohort from Dubai schools within capacity building module on heat stress management at workplace has been carried out on a total of 57 teachers and nurses working at Dubai private school’s physical education teachers and science teachers a long with school nurses. Well-developed capacity building module has been prepared and accredited by School Health department and public health department included theoretical part on heat stress and its related sequences in terms of mortalities and morbidities, as well as an approach to prevention and control, followed by practical demonstration and on life training sessions on steps of managements and levels of response. One full day training coverage along with initial written and verbal assessment and final written and verbal assessment based on scoring and scaling measurements. The training exercise has been standardized with the best practice training modules applied worldwide. Results: The study reflected that about 50.8% of the total contributors to the heat stress capacity building module were school’s teachers whom having direct supervision responsibilities with outdoor student’s activities, and 15% of the trainees were teachers of physical education, in total of 65% of the trainees were school teachers. The study showed that about 22% of the enrolment in capacity building was other school staff including administrators and other schools operating staff, the grant total of the trainees was 87.8%. The current study concludes that 7% of the total participant who are not ever limits outdoor activities which is in the coolest part of the day associated towards before capacity building program and 35.1% of the participants never carrying out a heat stress awareness program in your school, about 33.3% were un able to recognize and never seen a child with signs and symptoms of Heat stress in school. About 29.9% never received any training or awareness on heat stress, 5.3% never applied preventive measures/ procedures against heat stress in their schools.68.4% they were in favour of giving cold soda drinks to prevent heat and 61.4% were in favour of giving hot tea/coffee to prevent heat stress. The study showed improvement in heat stress management score among the participant in relation to (When children are playing outside in hot and humid weather the recommended drink to give). (I would call 999, if I see the child's body is recognition of high air temperature. If a child gets unconscious while playing outside, immediately give cold water) and recognition of signs of heat stress adequately). Conclusion: Workers have been suffering from illness related to heat because increasing heat exposure is becoming the challenges to them. However, the extreme hot environments are very dangerous to workers, who exposed to extreme heat. They are at high risked of the heat stress. The workers are unknown about heat exposer from the workplace and high influence of heat, so they are suffered from the underreporting of heat illnesses. Meanwhile, the lack of awareness about heat exposure associated with increase the risk of work- related injuries. Recommendations: As heat stress can be lethal and it is 100% preventable using common sense, thus developing competent school based heath stress prevention and management capacity building module at school’s

Strategies and factors associated with preparing for competing in the heat: a cohort study at the 2015 IAAF World Athletics Championships

PurposeAssess exertional heat illness (EHI) history and preparedness in athletes competing in a World Athletics Championships under hot/humid conditions and identify the factors associated with preparedness strategies.MethodsOf the 207 registered...

Investigation of heat stress and heat strain in outdoor workers: a case study in Iran

Heat stress is an important and serious threat at work and is a particular concern in outdoor occupational environments. This study aims at comparing heat stress and heat strain at different outdoor groups, examining the protective and adaptive actions which were done by workers and also provi services to them by government or employer to reduce heat load. This cross–sectional study was conducted in the hottest days of the summer 2015 in Shabestar, Iran and 53 healthy men in nine occupational groups including concrete makers, porters, construction, waste site and road making workers, stonemasons, farmers, traffic officers, and street vendors participated. A set of physiological parameters, like heart rate, blood pressure, skin temperature and etc., WBGT index details and some of the adaptive and protective parameters were measured and monitored simultaneously at different times of the day. The study finds that heat exposure in outdoor workplace is prevalent and WBGT TWA/TLV ave is less than 1 in some groups like stonemasons, waste site workers, traffic officers and street vendors whereas in other studied occupations, it is more than 1.This matter is compounded by the fact that the provision of health services by employers or local government was limited, and almost all of the participants had poor or insufficient access levels to public health and welfare services. This study confirms the necessity of interventions by a range of factors, such as government plans, improvement of services in the prevention of heat stress, and planning training courses for outdoor workers to build their knowledge of heat stress .

The Effect of Air Velocity on the Prevention of Heat Stress in Iranian Veiled Females

Background: Some environmental factors such as the ambient temperature, radiant temperature, humidity and air velocity as well as clothing and activity level are effective to induce heat strain on the workers. Objectives: The current study aimed to evaluate the effect of air velocity on Iranian veiled females at various exercise intensities and climatic conditions. Methods: The current experimental study was conducted on 51 healthy veiled females with Islamic clothing (n = 30) in two hot-dry climatic chambers (wet-bulb globe temperature (WBGT) = 32 ± 0.1°C and WBGT = 30 ± 0.1°C, 40% relative humidity (RH) without air velocity and (n = 21) with air velocity 0.31 m/s in sitting and light workload conditions, respectively, for 60 minutes. The WBGT, oral temperature and heart rate were measured simultaneously every five minutes during the heat exposure and resting state. Data were analyzed using correlation and line regression by SPSS ver. 16. Results: In both groups, oral temperature and heart rate increased during heat exposure. The increase of oral temperature and heart rate were larger in the group with air velocity (sitting position, 37.05 ± 0.20°C, 98.30 ± 7.79 bpm, light workload, 37.34 ± 0.24°C, 124.08 ± 6.09 bpm) compared those of the group without air velocity (sitting position, 36.70 ± 0.36°C, 69.74 ± 0.98 bpm, light workload, 36.71 ± 0.27°C, 110.78 ± 17.9 bpm). The difference in physiological strain index (PSI) between resting and low workload were higher in with air velocity group than those of the group without air velocity. Conclusions: The results showed that the heat stress increased by increasing air velocity and humidity in both groups. The air velocity with high humidity can be considered as a positive factor in the occurrence of heat strain. Therefore, the incidence of heat stress decreases with the increase of humidity and reduction of air velocity or with increase of air velocity and reduction of humidity in Iranian veiled females.

Intervention to reduce heat stress and improve efficiency among sugarcane workers in El Salvador: Phase 1

BackgroundChronic heat stress and dehydration from strenuous work in hot environments is considered an essential component of the epidemic of chronic kidney disease in Central America.Objective(1) To assess feasibility of...

On the management and prevention of heat stress for crews onboard ships

From the thermo-hygrometrical perspective, some ship compartments are undoubtedly considered severe hot environments due to high temperature values, such as the engine room and, depending on external conditions, cargo holds and storage areas. Such peculiarity further increases already high stress levels related to awkward work postures, lack of space and appropriate lifting tools, noise, vibrations, and a poor air quality. Despite the extensive efforts made by National Governments and International Organizations to improve the quality and the safety of the work on board, over the last several years the thermo-hygrometric characterization of working conditions on board ship seems to have not been investigated enough. Particularly, little monitoring data are available and the use of obsolete or insufficiently validated heat stress indices is a common practice. Addressed to both trained and untrained specialists, this paper discusses how the ergonomic approach of the strategy SOBANE – successfully used for 15 years for risk management and prevention in industrial application – can be implemented on-board. Finally, based on the limited microclimatic data available in the literature, it will be shown which and how heat strain indices should be used for the analysis of heat stress on board.

Ebola Response: Modeling the Risk of Heat Stress from Personal Protective Clothing.

IntroductionA significant number of healthcare workers have responded to aid in the relief and containment of the 2013 Ebola virus disease (EVD) outbreak in West Africa. Healthcare workers are required to wear personal protective clothing (PPC) to impede the transmission of the virus; however, the impermeable design and the hot humid environment lead to risk of heat stress.ObjectiveProvide healthcare workers quantitative modeling and analysis to aid in the prevention of heat stress while wearing PPC in West Africa.MethodsA sweating thermal manikin was used to measure the thermal (Rct) and evaporative resistance (Ret) of the five currently used levels of PPC for healthcare workers in the West Africa EVD response. Mathematical methods of predicting the rise in core body temperature (Tc) in response to clothing, activity, and environment was used to simulate different responses to PPC levels, individual body sizes, and two hot humid conditions: morning/evening (air temperature: 25°C, relative humidity: 40%, mean radiant temperature: 35°C, wind velocity: 1 m/s) and mid-day (30°C, 60%, 70°C, 1 m/s).ResultsNearly still air (0.4 m/s) measures of Rct ranged from 0.18 to 0.26 m2 K/W and Ret ranged from 25.53 to 340.26 m2 Pa/W.ConclusionBiophysical assessments and modeling in this study provide quantitative guidance for prevention of heat stress of healthcare workers wearing PPC responding to the EVD outbreak in West Africa.

Occupational heat-related illness emergency department visits and inpatient hospitalizations in the southeast region, 2007-2011.

Heat-related illness (HRI) is an occupational health risk for many outdoor, and some indoor, workers. Emergency department (ED) and inpatient hospitalization (IH) data for 2007-2011 from nine southeast states were analyzed to identify occupational HRI numbers and rates, demographic characteristics, and co-morbid conditions. There were 8,315 occupational HRI ED visits (6.5/100,000 workers) and 1,051 IHs (0.61/100,000) in the southeast over the study period. Out-of-state residents comprised 8% of ED visits and 12% of IHs. Rates for both, ED visits and IHs were significantly elevated in males and blacks. Younger workers had elevated rates for ED visits, while older workers had higher IH rates. This is the first study to evaluate occupational HRI ED visits and IHs in the southeast region and indicates the need for enhanced heat-stress prevention policies in the southeast. Findings from this study can be used to direct state health department tracking and evaluation of occupational HRI.

Perceptions of Workplace Heat Exposure and Controls among Occupational Hygienists and Relevant Specialists in Australia.

With warmer weather projections, workplace heat exposure is presenting a growing challenge to workers’ health and safety. Occupational hygienists are the specialist group conducting measurements and providing advice on heat stress management to industry. In order to provide insights into hygienists perceptions on workplace heat exposure, current and future preparedness for extreme heat, and barriers to possible heat adaptation strategies, a self-administered questionnaire survey was conducted during a national conference of the Australian Institute of Occupational Hygienists. Nearly 90% of the 180 respondents were at least moderately concerned about extreme heat and 19% were dissatisfied with current heat stress prevention measures. Barriers recognized by the participants were lack of awareness (68%), insufficient training (56%), unsatisfactory management commitment (52%), and low compliance with prevention policies (40%). The findings suggest a need to refine occupational heat management and prevention strategies.

HEAT STRESS IN POULTRY. II. METHODS AND TECHNIQUES FOR PREVENTION AND ALLEVIATION (review)

An adverse effect of heat stress in poultry depends on both the external factors such as diet, water supply, rearing technology, birds’ population density, air humidity and flow rate, etc., and the internal factors, particularly, poultry species and breed specificity, physiological conditions, etc. Herein, the approaches to prevention and alleviation of heat stress in poultry are summarized and discussed. Different strategies were proposed for lowering of body heat production and for better heat dissipation, thus maintaining productivity and product quality and minimizing losses for poultry farms. These strategies include the increase in energetic level of a diet in accordance with decrease in feed consumption due to stress (N.J. Daghir, 2009) and inclusion of higher (up to 4-5 %) levels of fat (B.L. Red, 1981; N. Usayran et al., 2001; A.A. Ghazalah et al., 2008); decrease by 2-4 % of dietary crude protein (Q.U. Zaman et al., 2008) and carbohydrate levels (metabolization of fat produces less heat than protein and carbohydrates) (N.A. Musharaf, J.D. Latshaw, 1999; N.J. Daghir, 2008); changes in amino acid profile of a diet (diets imbalanced in amino acids may increase heat production; moreover, requirements in lysine and sulfur-containing amino acids are much higher in heat stressed poultry) (R.M. Gous, T.R. Morris, 2005; S. Syafwan et al., 2011; O. Vjreck, M. Kirchgessner, 1980); supplementation with additional 250 ppm of vitamin C (M. Ciftci et al., 2005; A. Kavtarashvili, T. Kolokolnikova, 2010), 200 ppm of vitamin E (Z.Y. Niu et al., 2009; A.A. Rashidi et al., 2010), 8000 IU/kg of vitamin A (H. Lin et al., 2002), minerals or proper premix of vitamins and minerals (V.I. Fisinin et al., 2009), supplementation of feed or drinking water with electrolytes NaHCO3, KСl, CaCl2, NH4Cl (R.G. Teeter et al., 1985; T. Ahmad et al., 2005); pelleting of diets (R.M. Gous, T.R. Morris, 2005; A. Kavtarashvili, T. Kolokolnikova, 2010); special regimes of feeding (K. Hiramoto et al., 1995; M.H. Uzum, H.D. Oral Toplu, 2013) and intermitted lighting (A. Kavtarashvili, T. Kolokolnikova, 2010; D. Balnave, S.K. Muheereza, 1998); periodic (in 7-day periods) substitution of soda (NaHCO3) for 50-80 % of dietary salt (P.S. Silva et al., 1996; A. Kavtarashvili et al., 2010); feeding of mixture of ground mussel and lime (1:1) from separate feeders with simultaneous decrease in dietary Ca level; inclusion of dietary enzyme preparations (V.I. Fisinin et al., 1999) and probiotic strains of Lactobacillus (P.T. Lan et al., 2004); the use of special anti-stress additives and preparations (P. Surai et al., 2012; Р. Surai et al., 2013); moistening of enzyme-supplemented diets (H. Lin et al., 2006; M.A. Khoa, 2007); increase in air velocity in poultry houses up to 2.0-2.5 m/s (J. Donald, 2000); tunnel ventilation systems (M. Czarick, B.L. Tyson, 1989); systems of evaporative air cooling (J. Donald, 2000; E.S. Mailyan, 2007); the use of heat-insulating and light-reflective roof materials, sprinkling of roof with cold water (S. Yahav et al., 2004); 15-20 % decrease in stock density (T. Ahmad et al., 2006); a decreased litter thickness (to 3-5 cm) (Salah H.M. Esmail, 2001); decrease in any disturbing activity (vaccination, repopulation etc.) during the hottest hours; providing poultry with constant access to water including days when poultry is vaccinated via water; elimination of spray vaccines during heat stress (O. Mikhailovskaya et al., 2010); regular cleaning and disinfection of drinking water and drinking systems; acidification of drinking water (A. Kavtarashvili, 2013); regular refilling of drinking system with fresh and cold water; isolation and shading of water tanks and pipes exposed to direct sunlight; cooling of drinking water (S. Yahav et al., 1996); thermal training of embryos during 2nd half of embryogenesis (Y. Piestun et al., 2008) and 3-day chicks (S. Yahav et al., 2001; S. Yahav et al. 2004); genetic improvements in thermal tolerance (A.V. Miftahutdinov, 2011) including activated expression of naked neck gene Na and frizzle feather gene F (N. Deeb et al., 2001; M.V. Raju et al., 2004).

Relationship between physical attributes and heat stress in dairy cattle from different genetic groups.

Dairy cattle raised under harsh conditions have to adapt and prevent heat stress. The aim of this study was to evaluate physical characteristics and their association with heat tolerance in different genetic groups of dairy cattle. Thickness of the skin and coat, length and number of hairs, body measurements, as well as physiological parameters and body temperatures by infrared thermography were determined in 19 Holstein and 19 Girolando (½ and ¾ Holstein) cows. The Holstein cattle were less tolerant to heat stress than Girolando (GH50 and GH75 Holstein), because of the difficulty in dissipating heat due to the larger body size, as well as thicker and longer hairs. The correlations between physical characteristics, physiological parameters, and thermographic measurements prove to be inconsistent among genetic groups and therefore are not predictive of heat tolerance, while the regressions of morphometric characteristics on physiological and thermographic measures were not significant. Thus, the physical characteristics were not good predictors of physiological indices and thermographic temperature and so should not be used.

Effects of prolonged exposure of mouse embryos to elevated temperatures on embryonic developmental competence

To investigate effects of heat stress on developmental competence, in-vitro fertilized zygotes were incubated at different temperatures until 96 h post human chorionic gonadotrophin (HCG). Under severe and moderate conditions (41°C and 40°C), most embryos did not overcome the 2-cell block. In long-term mild heat stress (39°C until 96 h post HCG), cleavage and blastocyst formation were comparable to non-heat-stress control, but the number of live pups per transferred embryo and mean litter size were significantly affected (P < 0.05) in the mild-heat-stress group (19.4%, and 5.1 ± 0.4, respectively), compared with control (41.7% and 8.3 ± 0.3, respectively). To elucidate the different competence, gene expression was examined and the numbers of inner cell mass (ICM) and trophectoderm (TE) cells were counted. Aberrant expression of genes for embryonic viability and trophoblast differentiation in the mild-heat-stressed blastocysts was found. Moreover, the expanded blastocysts in the heat-stressed group and the control had a ICM:TE ratio of 1:2.47 and 1:2.96 with average total cell numbers of 59.21 ± 2.38 and 72.79 ± 2.40, respectively (P < 0.05), indicating lower cell numbers in TE. These findings underscore that prevention of heat stress in early embryos is important for maintaining embryo viability embryos during pregnancy.

AMELIORATIVE EFFECT OF ASCORBIC ACID ADMINISTRATION AND CHILLED DRINKING WATER ON RAM LAMBS EXPOSED TO HEAT STRESS DURING SUMMER SEASON.

ABSTRACTThe ameliorative effect of ascorbic acid supplementation and drinking chilled water on heat stress was studied on ram lambs. Twenty male ram lambs were randomly divided into four equal groups of five animals each and nearly similar in age and weight. The 1st group served as control (CTR), the 2nd group was given cold water (10-15 °C) without adding vitamin C (G1), the 3rd group was supplemented with ascorbic acid at rate 2.5 g/h/d (G2), the 4th group was supplemented with ascorbic acid in addition to the cold water (G3). All animals exposed to the same managerial and climatic condition during the complete experimental period. Body weight (BW) recorded at the beginning, then at biweekly intervals until end of the experiment. Feed intake, feed conversion efficiency, water intake per unit body gain and water intake per unit feed intake were calculated for each lamb. Rectal and ear temperatures, respiratory and pulse rates were measured. Blood plasma samples were analyzed for some blood constituents (total protein, albumin, globulin, glucose, total cholesterol, ALT, AST, calcium (Ca++) and potassium (K+)). Total protein, albumin, globulin, glucose, cholesterol and calcium concentrations were significantly higher (P≤0.001), however liver enzymes AST and ALT were significantly lower (P≤0.001) in the blood plasma of treated lambs (G1, G2 and G3) than those in control group. Cumulative feed intake, body weight gain, and cumulative water intake were significantly higher (P≤0.01) in G3 than other three groups. Rectal temperature (P≤0.05), respiration rate and pulse rate (P≤0.01) increased significantly, while ear temperature was not significantly affected by treatment. In conclusion, ascorbic acid supplementation ameliorates the adverse effect of heat stress during summer season. The body temperature, respiration and pulse rates have decreased as a result of the use of cold water or supply of ascorbic acid. Therefore, availability of cold water is paramount to prevent heat stress in sheep, especially during periods of extended hot and humidity.

A virtual rat for simulating environmental and exertional heat stress.

Severe cases of environmental or exertional heat stress can lead to varying degrees of organ dysfunction. To understand heat-injury progression and develop efficient management and mitigation strategies, it is critical to determine the thermal response in susceptible organs under different heat-stress conditions. To this end, we used our previously published virtual rat, which is capable of computing the spatiotemporal temperature distribution in the animal, and extended it to simulate various heat-stress scenarios, including 1) different environmental conditions, 2) exertional heat stress, 3) circadian rhythm effect on the thermal response, and 4) whole body cooling. Our predictions were consistent with published in vivo temperature measurements for all cases, validating our simulations. We observed a differential thermal response in the organs, with the liver experiencing the highest temperatures for all environmental and exertional heat-stress cases. For every 3°C rise in the external temperature from 40 to 46°C, core and organ temperatures increased by ∼0.8°C. Core temperatures increased by 2.6 and 4.1°C for increases in exercise intensity from rest to 75 and 100% of maximal O2 consumption, respectively. We also found differences as large as 0.8°C in organ temperatures for the same heat stress induced at different times during the day. Even after whole body cooling at a relatively low external temperature (1°C for 20 min), average organ temperatures were still elevated by 2.3 to 2.5°C compared with normothermia. These results can be used to optimize experimental protocol designs, reduce the amount of animal experimentation, and design and test improved heat-stress prevention and management strategies.

Managing animal wellbeing: a preliminary survey of pig farmers.

To gather information on producers' perceptions and management strategies towards the detection, alleviation of pain and management of sick, injured and heat-stressed pigs. A total of 16 Victorian pig farmers completed a face-to-face questionnaire consisting of 9 open and 26 closed questions regarding their detection and management of sick, injured and heat-stressed pigs and their perceptions of pigs' tolerance to pain. We identified 15 behavioural and physiological indicators of pain and heat stress. Treatment records were kept more often for weaned progeny and lactating sows than for piglets and mated sows. Most producers felt that pigs suffered little pain from routine husbandry procedures and that pain relief was not warranted in those situations. Castration at 10 days of age was the only procedure considered by producers to be very painful. There were inconsistencies in approaches to treating pigs in three case studies of animals with sickness or injury of varying severity. Meloxicam was stated as the most common anti-inflammatory drug used on-farm. A small proportion of farmers incorrectly identified antibiotics as anti-inflammatory drugs. All producers had at least one cooling system in place for preventing heat stress in pigs. The farmers in this survey group generally relied on behavioural changes in pigs to signal pain and heat stress. Although producers kept treatment records and used hospital pens for compromised pigs, our results suggest that the monitoring of pigs' recovery could be improved. Producers generally have a good understanding of the use of anti-inflammatory drugs to aid recovery of pigs.

Identifying Vulnerable Populations in Subtropical Brisbane, Australia: A Guide for Heatwave Preparedness and Health Promotion

Building healthy societies is a key step towards climate resilient communities. Ill health is related to increased risk during heat events and is disproportionally distributed within and between communities. To understand the differences in the spatial distribution of climate related health risks and how this will change in the future we have undertaken a spatiotemporal analysis of heatwave risks in urban populations in Brisbane, Australia. The aim of this was to advise emergency managers and public health authorities of high-risk areas during extreme heat events (EHEs). The spatial distribution of heat related morbidity identified areas of high healthcare service demand during EHEs. An index of risk was developed based on social and environmental determinants of vulnerability. Regression analysis was used to determine the key drivers of heat related morbidity from the index. A weighted map of population vulnerability was produced which identified the high risk areas and provided key information to target public health interventions and heat stress prevention policy. The predicted changes in high risk populations such as the proportion of elderly people living in urban areas were also mapped to support longer term adaptation and develop health care infrastructure and health promotion strategies.