Emergence of heat stress hazards in the CMIP6 models

2020 ◽  
Author(s):  
Natalie S. Lord ◽  
Dann M. Mitchell
Keyword(s):  
Heat Stress ◽  
Mortality Rates ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Number Of Factors ◽  
Event Attribution ◽  
Wide Range ◽  
Effects Of Temperature ◽  
The Impact ◽  
Extreme Heat Stress

<p>Hazards associated with the combined effects of temperature and humidity can have a wide range of impacts, particularly on human health and agriculture. The human body removes metabolic heat through sweating and heat conduction, and the efficiency of these processes is reduced when ambient temperatures and humidity are high, resulting in heat stress. The effects of this range from general discomfort to increased morbidity and mortality rates, trends that have been observed during recent severe heatwaves such as those that occurred during the summer of 2019 in Europe. A number of factors may exacerbate heat stress, including intense physical activity and being located in an urban area as opposed to a rural area.</p><p>As global temperatures increase, the risk associated with heat stress hazards is expected to increase, and this signal is expected to emerge from natural variability over the coming decades, if not sooner. Here, simulations from the new CMIP6 models are analysed to investigate the timing of emergence of heat stress hazards, in order to identify regions of the globe that are particularly vulnerable to extreme heat stress and/or imminent emergence of these hazards. Event attribution techniques are also applied to estimate the impact of anthropogenic warming on the hazard risk.</p>

scholarly journals Review: Impacts of shade on cattle well-being in the beef supply chain

2020 ◽  
Author(s):  
Lily N Edwards-Callaway ◽  
M Caitlin Cramer ◽  
Caitlin N Cadaret ◽  
Elizabeth J Bigler ◽  
Terry E Engle ◽  
...  
Keyword(s):  
Supply Chain ◽  
Heat Stress ◽  
Beef Cattle ◽  
Production Systems ◽  
Construction Materials ◽  
Well Being ◽  
Third Party ◽  
Ambient Temperatures ◽  
Stress Susceptibility ◽  
The Impact

ABSTRACT Shade is a mechanism to reduce heat load providing cattle with an environment supportive of their welfare needs. Although heat stress has been extensively reviewed, researched, and addressed in dairy production systems, it has not been investigated in the same manner in the beef cattle supply chain. Like all animals, beef cattle are susceptible to heat stress if they are unable to dissipate heat during times of elevated ambient temperatures. There are many factors that impact heat stress susceptibility in beef cattle throughout the different supply chain sectors, many of which relate to the production system, i.e. availability of shade, microclimate of environment, and nutrition management. The results from studies evaluating the effects of shade on production and welfare are difficult to compare due to variation in structural design, construction materials used, height, shape, and area of shade provided. Additionally, depending on operation location, shade may or may not be beneficial during all times of the year, which can influence the decision to make shade a permanent part of management systems. Shade has been shown to lessen the physiologic response of cattle to heat stress. Shaded cattle exhibit lower respiration rates, body temperatures, and panting scores compared to un-shaded cattle in weather that increases the risk of heat stress. Results from studies investigating the provision of shade indicate that cattle seek shade in hot weather. The impact of shade on behavioral patterns is inconsistent in the current body of research, some studies indicating shade provision impacts behavior and other studies reporting no difference between shaded and un-shaded groups. Analysis of performance and carcass characteristics across feedlot studies demonstrated that shaded cattle had increased ADG, improved feed efficiency, HCW, and dressing percentage when compared to cattle without shade. Despite the documented benefits of shade, current industry statistics, although severely limited in scope, indicate low shade implementation rates in feedlots and data in other supply chain sectors do not exist. Industry guidelines and third party on-farm certification programs articulate the critical need for protection from extreme weather but are not consistent in providing specific recommendations and requirements. Future efforts should include: updated economic analyses of cost versus benefit of shade implementation, exploration of producer perspectives and needs relative to shade, consideration of shade impacts in the cow-calf and slaughter plant segments of the supply chain, and integration of indicators of affective (mental) state and preference in research studies to enhance the holistic assessment of cattle welfare.

Energy intake and fur in summer- and winter-acclimated Siberian hamsters (Phodopus sungorus)

2001 ◽  
Vol 281 (2) ◽  
pp. R519-R527 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Alessandra Cabrera ◽  
Irving Zucker
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Ventral Surface ◽  
Phodopus Sungorus ◽  
Ambient Temperatures ◽  
Siberian Hamsters ◽  
Daily Food ◽  
Brown Adipose ◽  
Wide Range ◽  
The Impact

Few studies have directly addressed the impact of fur on seasonal changes in energy intake. The daily food intake of Siberian hamsters ( Phodopus sungorus) was measured under simulated summer and winter conditions in intact animals and those with varying amounts of pelage removed. Energy intake increased up to 44% above baseline control values for approximately 2–3 wk after complete shaving. Increases in food intake varied with condition and were greater in hamsters housed in short than long day lengths and at low (5°C) than moderate (23°C) ambient temperatures. Removal of 8 cm2 of dorsal fur, equivalent to 30% of the total dorsal fur surface, increased food intake, but removal of 4 cm2 had no effect. An 8-cm2 fur extirpation from the ventral surface did not increase food consumption. Food intake was not influenced differentially by fur removal from above brown adipose tissue hot spots. Fur plays a greater role in energy balance in winter- than summer-acclimated hamsters and conserves energy under a wide range of environmental conditions.

Regulated hypothermia in the hypothyroid rat induced by administration of propylthiouracil

1997 ◽  
Vol 272 (5) ◽  
pp. R1390-R1395 ◽  
Author(s):  
Y. Yang ◽  
C. J. Gordon
Keyword(s):  
Drinking Water ◽  
Heat Stress ◽  
Temperature Gradient ◽  
Serum Levels ◽  
Male Rats ◽  
Light Phase ◽  
Grooming Behavior ◽  
Ambient Temperatures ◽  
Wide Range ◽  
The Stability

Propylthiouracil (PTU), an antithyroidal drug that reduces serum L-thyroxine (T4) and 3,5,3'-triiodothyronine (T3), is presumed to lower core temperature (T0) by impairing metabolic thermogenesis. However, it is not understood why PTU-treated animals cannot use behavioral and other thermoeffectors to maintain normal Tc. Male rats were administered PTU in drinking water (0.05 mg/ml) while the following parameters were measured: 1) Tc and motor activity (MA) recorded by radiotelemetry for 24 h at ambient temperatures (Ta) of 10-30 degrees C; 2) selected Ta, MA, and Tc in a temperature gradient; and 3) Tc, MA, and grooming behavior during exposure to heat stress (TH = 34.5 degrees C) for 2 h. PTU reduced serum levels of T4, and T3 by 95 and 60%, respectively. Tc decreased after 3 days of PTU treatment; a 0.5 degree C decrease in Tc persisted throughout the PTU treatment. PTU rats exposed to Ta of 10-30 degrees C maintained a consistent hypothermic Tc during the light phase; however, a deficit in the stability of Tc at night was noted during exposure to 10 degrees C. In the temperature gradient, PTU rats selected warmer Ta, but their Tc was maintained at the same hypothermic levels as observed at fixed Ta values of 15-30 degrees C. Heat stress caused Tc of control rats to increase to 39 degrees C, whereas Tc of the PTU rats was maintained below 38 degrees C. The regulation of Tc at hypothermic levels over a wide range of Ta values and when rats were housed in a temperature gradient indicates that chronic PTU induces a state of regulated hypothermia.

“On Deposit”: animal acquisition at the Zoological Society of London, 1870–1910 (Patron's review)

2021 ◽  
Vol 48 (1) ◽  
pp. 1-21
Author(s):  
Eleanor Larsson
Keyword(s):  
High Mortality ◽  
Mortality Rates ◽  
The Public ◽  
Zoological Society ◽  
Wide Range ◽  
Regent's Park ◽  
The Impact ◽  
Animal Trade ◽  
Lack Of Knowledge

When the zoological gardens in Regent's Park opened to the public in 1847, they immediately became very popular, providing a source of both entertainment and instruction for visitors and a vital stream of revenue for the Zoological Society of London. However, the ongoing popularity of the gardens was endangered by the consistently high mortality rates which afflicted the Society's animals throughout the course of the nineteenth and early-twentieth centuries. This paper examines how the Society's efforts to combat this challenge led them to foster and sustain relationships which centred on the act of animal “deposit”. Often a temporary arrangement, somewhat like a loan, depositing involved a range of individuals involved in the animal trade, including commercial animal dealers and the naturalist Lionel Walter Rothschild. Through the system of depositing, the Zoological Society became the custodians of a wide range of animals which they could exhibit. However, their lack of ownership of these animals, combined with a lack of knowledge about how to care for them, ultimately constrained the Society's management of them and impeded its longer-term goals of reducing both animal mortality and the impact of high mortality rates on the menagerie's ability to attract visitors and sustain its economy.

Impact of mortality, possibly due to herpesvirus, on pilchard Sardinops sagax stocks along the south coast of Western Australia in 1998-99

2000 ◽  
Vol 51 (6) ◽  
pp. 601 ◽  
Author(s):  
D. J. Gaughan ◽  
R. W. Mitchell ◽  
S. J. Blight
Keyword(s):  
Western Australia ◽  
Total Mortality ◽  
Simulation Models ◽  
Mortality Rates ◽  
Sea Surface ◽  
Sea Floor ◽  
Wide Range ◽  
The Mean ◽  
The Difference ◽  
The Impact

During progression of a mass mortality of Australian pilchards in late 1998 and early 1999, quantities of dead pilchards on the sea-surface, sea-floor and along beaches were estimated in three regions along southern Western Australia (WA) by use of transects. Total mortality was estimated at 17 590, 11193 and 144.4 t for Esperance, Bremer Bay and Albany respectively. Mortality rates at Esperance and Bremer Bay were similar at 74.5% and 64.7% respectively, with a mean of 69.6%. In contrast, estimated mortality at Albany was only 2.4%. Although the difference in total mortality between regions is probably related to differences in stock size, as determined by simulation models, the much lower estimate for Albany is probably an artefact of an over-estimated pilchard biomass and not due to large differences in actual mortality rates. Variability in estimates of both pilchard biomass and quantities killed resulted in a wide range of estimated mortality rates, with lower estimates for Esperance and Bremer Bay of 28.0% and 22.9% respectively. This represents a significant decline in the breeding stock of WA pilchards. If the impact was closer to the mean (69.6%), then pilchard stocks in WA are severely depressed.

The effects of temperature and relative humidity on the thermoregulatory responses of grouped and isolated neonate chicks

1976 ◽  
Vol 86 (1) ◽  
pp. 35-43 ◽  
Author(s):  
B. H. Misson
Keyword(s):  
Body Size ◽  
Relative Humidity ◽  
Rectal Temperature ◽  
Heat Production ◽  
Water Loss ◽  
Evaporative Heat Loss ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Effects Of Temperature

SUMMARYMeasurements of O2 consumption (Vo2), CO2 production (VCO2) evaporative water loss and rectal temperature (Tr) have been made and metabolic heat production (H), evaporative heat loss (—E) and respiratory quotient (RQ) calculated with individual and groups of 1-day-old chicks at constant ambient temperatures (To) in the range 20—43 °C and 80 or 20% relative humidity (R.H.).Minimal metabolism (10·7 kJ/kgJ/h) occurred at 35 °C.One-day-old chicks act as heterotherms outside the zone of minimal metabolism since neither H nor —E are sufficiently developed mechanisms to maintain homeothermy.Huddling allows chicks to maintain a higher TT at a lower H per unit metabolic body size.Reducing E.H. from 80 to 20% raised the upper temperature survival limit (UTSL) from 41·5 to 43 °C.Panting was initiated when Ta = 38 °C and Tr was between 39·5 and 39·9 °C.

Chronic antioxidant enzyme mimetic treatment differentially modulates hyperthermia-induced liver HSP70 expression with aging

2006 ◽  
Vol 100 (4) ◽  
pp. 1385-1391 ◽  
Author(s):  
Hannah J. Zhang ◽  
Susan R. Doctrow ◽  
Larry W. Oberley ◽  
Kevin C. Kregel
Keyword(s):  
Heat Stress ◽  
Recovery Period ◽  
Protein Accumulation ◽  
Mrna Levels ◽  
Hsp70 Mrna ◽  
Hsp70 Protein ◽  
Age Related ◽  
Wide Range ◽  
Old Rats ◽  
The Impact

One postulated mechanism for the reduction in stress tolerance with aging is a decline in the regulation of stress-responsive genes, such as inducible heat shock protein 72 (HSP70). Increased levels of oxidative stress are also associated with aging, but it is unclear what impact a prooxidant environment might have on HSP70 gene expression. This study utilized a superoxide dismutase/catalase mimetic (Eukarion-189) to evaluate the impact of a change in redox environment on age-related HSP70 responses to a physiologically relevant heat challenge. Results demonstrate that liver HSP70 mRNA and protein levels are reduced in old compared with young rats at selected time points over a 48-h recovery period following a heat-stress protocol. While chronic systemic administration of Eukarion-189 suppressed hyperthermia-induced liver HSP70 mRNA expression in both age groups, HSP70 protein accumulation was blunted in old rats but not in their young counterparts. These data suggest that a decline in HSP70 mRNA levels may be responsible for the reduction in HSP70 protein observed in old animals after heat stress. Furthermore, improvements in redox status were associated with reduced HSP70 mRNA levels in both young and old rats, but differential effects were manifested on protein expression, suggesting that HSP70 induction is differentially regulated with aging. These findings highlight the integrated mechanisms of stress protein regulation in eukaryotic organisms responding to environmental stress, which likely involve interactions between a wide range of cellular signals.

scholarly journals 3 Changes in growth performance, feeding behaviors, and posture behaviors of growing pigs subjected to low-intensity heat stress

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 3-4
Author(s):  
Lauren E Anderson ◽  
Jonathan P Holt ◽  
Eric van Heugten ◽  
Daniel H Poole
Keyword(s):  
Heat Stress ◽  
Growing Pigs ◽  
Feeding Behaviors ◽  
Ambient Temperatures ◽  
Low Intensity ◽  
Feeding Duration ◽  
Time Interaction ◽  
Useful Heat ◽  
Time Of Feeding ◽  
The Impact

Abstract This study was to determine the impact of low-intensity heat stress on frequency and duration of feeding, drinking, ventral lying, and lying lateral lying behaviors. Pigs (n = 64; 24.6 ± 3.7 kg BW) were housed four per pen in thermoneutral conditions (CON; 23.9 °C ± 2.5 °C) or constant high ambient temperatures (HS; 28.7 °C ± 1.3 °C) for 16 d, followed by thermoneutral conditions (24.4 °C ± 1.8 °C) for both groups through d 21, and subsequent heat stress (28.0 °C ± 3.0 °C) for both groups through d 30. Eight focal pigs (2 pens/treatment) were video-recorded on d 3, 6, 10, 13, 20, and 29 at three time periods (morning: 0600-0800, afternoon: 1200–1400, evening: 1800–2000). Heat stress reduced ADG (HS: 1.00 kg/d, CON: 1.13 kg/d; P = 0.020) from d 14 through d 21, tended to reduce ADFI (HS: 2.14 kg/d, CON: 2.24 kg/d; P = 0.085), and increased GF (HS: 0.62, CON: 0.52; P = 0.006) from d 1 through d 7. Surface body temperature from d 2 through d 15 was greater in HS than CON pigs (mean: 39.4 °C, 37.6 °C, respectively), and was lower on d 18 for HS than CON pigs (36.4 °C vs. 37.8 °C, respectively) and d 22 (38.6 °C vs 39.3 °C, respectively). A treatment x day x time interaction for feeding duration (P = 0.003) showed CON pigs spent longer at the feeder in the morning of d 6 than HS (22.70 min, 8.97 min, respectively), but CON spent less time than HS during d 6 evening (8.78 min, 19.57 min, respectively). HS pigs visited the feeder more frequently in the evening (14.4 bouts) than CON pigs (7.8 bouts; P = 0.029). Low-intensity heat stress negatively impacted performance and altered time of feeding duration and frequency, indicating feeding behavior may be a useful heat stress predictor.

scholarly journals PSI-4 Changes in serum cortisol concentrations and cytokine profiles of growing pigs subjected to low-intensity heat stress

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 266-267
Author(s):  
Lauren E Anderson ◽  
Jonathan P Holt ◽  
Eric van Heugten ◽  
Daniel H Poole
Keyword(s):  
Heat Stress ◽  
Serum Cortisol ◽  
Lung Lavage ◽  
Growing Pigs ◽  
Jejunal Mucosa ◽  
Ileal Mucosa ◽  
Ambient Temperatures ◽  
Low Intensity ◽  
Macrophage Colony ◽  
The Impact

Abstract This study was to determine the impact of low-intensity heat stress on inflammatory biomarkers in serum, ileum, jejunum and lung lavage samples. Pigs (n = 64; 24.6 ± 3.7 kg BW) were housed four per pen in thermoneutral conditions (CON; 23.9°C ± 2.5°C) or constant high ambient temperatures (HS; 28.7°C ± 1.3°C) for 16 d, followed by thermoneutral conditions (24.4°C ± 1.8°C) for both groups through d 21, and subsequent heat stress (28.0°C ± 3.0°C) for both groups through d 30. Respiration rate (P < 0.01) was greater in HS than CON pigs from d 2 through d 15 (mean: 82.54 breaths/min vs. 59.26 breaths/min). HS pigs had greater cortisol concentration (40.1 ng/mL vs. 27.3 ng/mL) than CON on d 2, but lower concentrations on d 22 (32.9 ng/mL vs. 48.9 ng/mL) and d 25 (25.4 ng/mL vs. 42.0 ng/mL; treatment x day: P < 0.001). HS pigs tended to have greater serum IL1β (190.1 vs. 143.4 pg/mL; P = 0.06) and greater serum IL12 concentrations (914.9 vs. 785.4 pg/mL; P < 0.01) than CON pigs. HS pigs tended to have greater ileal mucosa IL6 concentrations than CON pigs (50.4 vs. 30.9 pg/mL; P = 0.08). Jejunal mucosa IL1α concentrations tended (P = 0.10) to be greater for CON than HS pigs (13.5 vs. 9.0 pg/mL) and CON pigs had greater jejunal IL12 concentrations (18.1 vs. 11.8 pg/mL) than HS pigs (P = 0.02). Bronchioalveolar lavage from HS pigs tended (P = 0.10) to have a greater granulocyte-macrophage colony-stimulating factor concentration (6.9 vs. 5.3 pg/mL) than CON pigs and had greater IL4 (7.7 vs. 4.2 pg/mL) and IL12 concentrations (34.8 vs. 24.5 pg/mL) than CON pigs (P = 0.01). Increased inflammatory activity and endocrine stress response occurred during low-intensity heat stress, indicating it may be more detrimental than previously accepted.

scholarly journals Building Materials for Cities and Climate Change – a Material Catalogue with Recommendations

2021 ◽  
Vol 2042 (1) ◽  
pp. 012057
Author(s):  
C Hoffmann ◽  
A Geissler ◽  
M Mutti ◽  
A Wicki ◽  
F Schwager
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Building Materials ◽  
Data Sets ◽  
Night Time ◽  
Ambient Temperatures ◽  
Metal Sheets ◽  
Dark Color ◽  
Night Ventilation ◽  
The Impact

Abstract High urban density with heat accumulating materials and sealed surfaces can cause heat stress and reduced nocturnal cooling in summer. Appropriate building materials may contribute to the mitigation of this effect. The research project evaluates building materials for façades and outer surfaces (ground) on the resulting urban microclimate and on factors like glare, acoustics and embedded energy. The present publication focuses on the impact on the microclimate. The analysis comprises the simulation of forty-seven data sets in a microclimatic model with ENVI-met. The results show that during daytime the PET for the whole neighborhood ranges between 30.1 and 36.4 °C. Choosing a bright instead of a dark color can lower the PET between 0.2 and 1.0 K. Dark colored metal sheets may cause turbulences which lead to a reduction of the PET between 2.0 and 3.8 K (compared to a bright metal sheet). However, this effect may not be reproducible under varying boundary conditions. During night-time, the resulting span of ambient temperatures between the materials reaches 21.4 to 22.0 °C (level 1.7 m). The temperature difference between the materials at the level of 10.7 m (for night ventilation) is found to be approx. 0.3 K and can be considered irrelevant.

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