Broilers’ behavioural adjustments when submitted to natural heat stress and fed different maize particle sizes in the diet

2019 ◽  
Vol 157 (9-10) ◽  
pp. 743-748 ◽  
Author(s):  
M. M. Santos ◽  
J. B. F. Souza-Junior ◽  
J. P. A. F. Queiroz ◽  
M. K. O. Costa ◽  
H. F. F. Lima ◽  
...  
Keyword(s):  
Heat Stress ◽  
Feed Intake ◽  
Thermal Environment ◽  
Geometric Mean ◽  
Thermal Conditions ◽  
Time Of Day ◽  
Particle Sizes ◽  
Behavioural Adjustment ◽  
The Times ◽  
Body Heat

AbstractSince behavioural adjustments are an important line of defence against thermal stress, either due to their energy efficiency or to efficiency at preventing overheating, we aimed to evaluate whether broilers fed different maize particle sizes adjusted their behaviour to deal with heat stress challenges. At several times a day, the behaviour of 220 naked neck broilers was evaluated. These broilers were fed with isonutritive diets containing maize with different geometric mean diameters (GMD): 605 and 2280 μm. The thermal environment was monitored during the experiment. Panting and open wings were the only behaviours that showed differences between the times of day (P < 0.05). However, GMD showed a significant effect on feed intake and panting (P < 0.05). The interaction between GMD and time of day was significant only on panting (P < 0.05). Although no daily variation was observed, the highest feed intake was observed in broilers fed the diet containing maize with a GMD of 2280 μm. Less than 5% of the broilers were observed drinking water during the day. Open wings was the behavioural adjustment most used by broilers from 10:00 h, and remained elevated until 14:00 h for both GMDs. The birds panted more when fed the diet containing maize with a GMD of 2280 μm. In conclusion, broilers adjust their behaviour to dissipate excess body heat from the environment and as a result of feed intake. Coarse particles of maize in the diet increase the thermal challenge of broilers since the environment also provides stressful thermal conditions.

Some evidence of a time-varying thermal perception

2021 ◽  
pp. 1420326X2110345
Author(s):  
Marika Vellei ◽  
William O’Brien ◽  
Simon Martinez ◽  
Jérôme Le Dréau
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Time Of Day ◽  
Time Varying ◽  
Thermal Perception ◽  
Indoor Thermal Environment ◽  
Human Circadian Rhythm ◽  
Comfort Criteria

Recent research suggests that a time-varying indoor thermal environment can lead to energy savings and contribute to boost buildings' energy flexibility. However, thermal comfort standardization has so far considered thermal comfort criteria as constant throughout the day. In general, very little attention has been given to the ‘ time of day' variable in the context of thermal comfort research. In this paper, we show some evidence of a time-varying thermal perception by using: (1) data from about 10,000 connected Canadian thermostats made available as part of the ‘ Donate Your Data' dataset and (2) about 22,000 samples of complete (objective + ‘ right-here-right-now' subjective) thermal comfort field data from the ASHRAE I and SCATs datasets. We observe that occupants prefer colder thermal conditions at 14:00 and progressively warmer ones in the rest of the day, indistinctively in the morning and evening. Neutral temperature differences between 08:00 and 14:00 and 14:00 and 20:00 are estimated to be of the order of 2°C. We hypothesize that the human circadian rhythm is the cause of this difference. Nevertheless, the results of this study are only based on observational data. Thermal comfort experiments in controlled environmental chambers are required to confirm these findings and to better elucidate the effects of light and circadian timing and their interaction on thermal perception.

Behavioural effects of yearling grain-finished heifers exposed to differing environmental conditions and growth-promoting agents

2008 ◽  
Vol 48 (9) ◽  
pp. 1155 ◽  
Author(s):  
T. L. Mader ◽  
J. B. Gaughan ◽  
W. M. Kreikemeier ◽  
A. M. Parkhurst
Keyword(s):  
Heat Stress ◽  
Cold Stress ◽  
Feed Intake ◽  
Environmental Conditions ◽  
Time Of Day ◽  
Feedlot Cattle ◽  
Trenbolone Acetate ◽  
Growth Promoting ◽  
Adverse Environmental Conditions ◽  
Growth Promotants

Two groups of 108 Angus cross yearling heifers were utilised to determine the effects of growth-promoting agents on behaviour, when utilised under thermoneutral, hot and cold environmental conditions. Pens of heifers were observed throughout the day for feed intake pattern via bunk score, panting (hot), degree of bunching and shivering (cold). For cattle that were exposed to cold stress, feed intake was greater earlier in the day, with the majority of the feed consumed by 1500 hours and little or no feed consumed at night, while the opposite trend occurred under heat stress. Nearly 46% of the pens containing heat-stressed heifers had greater than 50% of their feed remaining in the bunk at 1900 hours. Pens of heifers exposed to thermoneutral conditions had a tendency to show elevated panting scores at 0700 hours, while heifers exposed to hot conditions did not, indicating some acclimation to heat stress had already taken place for the heifers exposed to hot conditions. Panting score did not appear to be affected by growth-promoting treatment. Under cold stress, 100% of the cattle displayed bunching behaviour throughout the day, while under hot and thermoneutral conditions, maximum bunching (25 to 30%) occurred at 1500 hours. Within an environmental condition, trenbolone acetate cattle tended to bunch more under thermoneutral and hot conditions, particularly in the morning, when compared with other treatment groups; control and oestrogen-treated cattle tended to bunch less under the same conditions, regardless of the time of day. Although data were inconclusive as to overall effects of growth promotants on mitigating cold stress, shivering scores were increased with a more aggressive growth-promoting treatment (P < 0.05). These findings suggest that if growth promotants, which are used in feedlot cattle, impact cattle exposed to adverse environmental conditions, then they tend to be more effective at mitigating heat stress than cold stress.

Differences of Hemorrhagic and Ischemic Strokes in Age Spectra and Responses to Climatic Thermal Conditions

2020 ◽  
Author(s):  
Pan Ma
Keyword(s):  
Heat Stress ◽  
Cold Stress ◽  
Thermal Environment ◽  
Age Groups ◽  
Additive Model ◽  
Thermal Conditions ◽  
Climate Index ◽  
Thermal Environments ◽  
Distributed Lag ◽  
And Gender

&lt;p&gt;The risks of Emergency Room (ER) visits for cerebral infarction (CI) and intracerebral hemorrhage (ICH) is found to differ in different age groups under different climatic thermal environments. Based on CI and ICH related ER-visit records from three major hospitals in Beijing, China, from 2008 to 2012, the advanced universal thermal climate index (UTCI), was adopted in this study to assess the climatic thermal environment. Particularly, daily mean UTCI was used as a predictor for the risk of ER visits for CI and ICH. A generalized quasi-Poisson additive model combined with a distributed lag non-linear model was performed to quantify their association. The results indicated that (&amp;#8560;) the highest growth rate of ER visits for ICH occurred in age 38 to 48, whereas an increasing ER admissions for CI maintained at age 38 to 78. (&amp;#8561;) The frequency distribution of UTCI in Beijing peaked at -8 and 30 &amp;#8451;, corresponding to moderate cold stress and moderate heat stress, respectively. (&amp;#8562;) Correlation analysis indicated that ICH morbidity was negatively correlated with UTCI, whereas occurrence of CI showed no significant association with UTCI. (&amp;#8563;) The estimated relative risk of ER visits corresponding to 1&amp;#8451; change in UTCI, which was then stratified by age and gender, indicated that all sub-groups of ICH patients responded similarly to thermal stress. Namely, there is an immediate ICH risk (UTCI = -13&amp;#8451;, RR=1.35, 95% CIs: 1.11~1.63) from cold stress on the onset day, but non-significant impact from heat stress. As for CI occurrences, no effect from cold stress was identified, except for only those aged 45 to 65 were threatened by heat stress (UTCI = 38&amp;#8451;, RR=1.64, 95% CIs: 1.10~2.44) on lag 0~2d.&amp;#160;&lt;/p&gt;

scholarly journals Can Mathematical Models of Body Heat Exchanges Accurately Predict Thermal Stress in Premature Neonates?

2019 ◽  
Vol 9 (8) ◽  
pp. 1541
Author(s):  
Stéphane Delanaud ◽  
Fatima Chahin Yassin ◽  
Estelle Durand ◽  
Pierre Tourneux ◽  
Jean-Pierre Libert
Keyword(s):  
Thermal Stress ◽  
Mathematical Models ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Premature Neonates ◽  
Clinical Centre ◽  
Plastic Bag ◽  
Heat Exchanges ◽  
Heat Transfers ◽  
Body Heat

Mathematical models of body heat exchanges can be used to define the thermal limits needed to protect premature neonates nursed in incubators against thermal stress–stress that can have potentially devastating impairments on neurological development and body growth. Predictive models can help caregivers to keep a neonate’s body temperature within the normal range and to solve problems that arise during intensive care, such as the risk of hyperthermia during phototherapy, the risk of hypothermia during transport from one clinical centre to another, and the use of a plastic bag to reduce skin water loss and body dehydration. Here, we review the strengths and limitations of models used to predict the risk of thermal stress, with a focus on uncertainties in the algorithms governing heat transfers between the neonate’s skin and the complicated thermal environment encountered in incubators. We describe attempts to reduce the large number of empirical assumptions and uncertainties in this field, and suggest ways of more accurately modelling optimal thermal conditions for neonates nursed in closed incubators.

scholarly journals PSIX-26 Effect of supplemental Arg on respiration rate and body temperature of pigs exposed to heat stress

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 351-351
Author(s):  
Adriana Morales Trejo ◽  
Fernanda González ◽  
Hugo Bernal ◽  
Miguel Cervantes ◽  
Caroline Gonzalez-Vega ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Heat Stress ◽  
Data Analysis ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Respiration Rate ◽  
Feed Intake ◽  
Well Being ◽  
Period 2 ◽  
Body Heat

Abstract Heat stress (HS) reduces feed intake and affects the well-being of pigs by increasing their body temperature (BT) and respiration rate (RR). Nitric oxide, an Arg metabolite, helps to dissipate body heat by stimulating blood vasodilation. Because reduced feed intake translates into decreased Arg consumption, the effect of supplementing Arg in the diet on BT and RR was analyzed using 8-ileal cannulated pigs (61.7±2.7 kg BW) exposed to HS. A thermometer set to register BT at 5-min intervals was implanted into the ileum. There were two treatments: control wheat-soybean meal plus free Lys-Thr diet (CON), and the CON diet added with 0.20% free Arg (ARG). The study was conducted in two-6 d periods; d1-d3 for diet adaptation and d4-d6 for BT data analysis. The RR (respirations per min - rpm) was measured in all pigs at 0600-h and 1600-h. Pigs were fed at 0700-h and 1900-h, 900 g/meal. Ambient temperature and relative humidity were: 28.2-to-34.6 °C, 53-to-82%, respectively. Ambient temperature and BT followed a similar pattern every day. There was no interaction in BT and RR between periods. Overall, BT of ARG pigs (40.75°C) was slightly lower (P &lt; 0.05) than in CON pigs (40.71°C). Arg supplementation greatly reduced RR (rpm) regardless of period and day time (P &lt; 0.05): overall (91, 73), period-1 (98, 78), period-2 (85, 68), 0600-h, (68, 52), 1600-h (115, 94), respectively. The RR at 0600-h (60) was lower than at 1400-h (109; P &lt; 0.05) regardless of diet. The reduced RR because of Arg supplementation may be explained as an increased synthesis of nitric oxide probably resulting in both increased vasodilation and dissipation of body heat. In conclusion, although supplemental Arg caused a modest decrease in BT, the large RR reduction may indicate that Arg might help to improve the welfare of HS pigs.

scholarly journals Bone parameters and organ morphometry of two broiler chicken lines exposed to heat for different periods

2019 ◽  
Vol 40 (5) ◽  
pp. 2007
Author(s):  
Cintia Amaral Moraes ◽  
João Paulo Rodrigues Bueno ◽  
Mara Regina Bueno de Mattos Nascimento ◽  
Fernanda Heloisa Litz ◽  
Luciana Ruggeri Menezes Gotardo ◽  
...  
Keyword(s):  
Small Intestine ◽  
Heat Stress ◽  
Thermal Environment ◽  
Heat Exposure ◽  
Thermal Conditions ◽  
Bursa Of Fabricius ◽  
Mineral Matter ◽  
Average Weight ◽  
Bone Parameters ◽  
Length Width

The objective of this study was to evaluate the effects of different times of exposure to heat on bone parameters and organ morphometry of Cobb Slow® and Hubbard Flex® broilers exposed to high temperatures for 1, 2 or 3 h daily, from 14 days of age. A total of 1120 one-day-old male chicks (half of each line; average weight of 44 g) were housed into 32 cages with 35 birds each, in a randomized-block experimental design. From the first to the 13th day of age, the birds remained under the thermal conditions recommended for their lines; thereafter, from the 14th day, the shed was separated into four parallel sections of 5.60 × 10.20 × 2.8 m delimited by double-sided plastic curtains along the width of the shed. Cyclic heat stress was generated by average temperatures of 36 ºC from 14-20 days, 35 °C from 21-27 days, 34 °C from 28-34 days and 33 °C from 35-42 days. The total length, width, density and mineral matter of the tibia; the size of the duodenum, jejunum and ileum; and the weights of the bursa of Fabricius and spleen were measured. No interaction effect between thermal environment and line was observed. Heat stress for up to 3 h daily, from the 14th to the 41st day of age, led to a longer but narrower tibia. There was no influence on small intestine morphometry. The Hubbard line presented longer and wider tibiae as well as higher relative and absolute weights of the bursa. In conclusion, heat stress from 2 h daily modifies the structure of the tibia in broilers, which increases in length and reduces in width, but heat exposure has no influence on the small intestine or lymphoid organs. The Hubbard line shows better tibia development than the Cobb line as well as different primary lymphoid responses, represented by a heavier bursa.

scholarly journals The Relationship between the Heat Disorder Incidence Rate and Heat Stress Indices at Yamanashi Prefecture in Japan

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Shin Akatsuka ◽  
Tadashi Uno ◽  
Masahiro Horiuchi
Keyword(s):  
Heat Stress ◽  
Incidence Rate ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Stress Index ◽  
Daily Maximum ◽  
Temperature Threshold ◽  
Stress Indices ◽  
The Relationship ◽  
Disorder Prevention

In recent years, the risk of heat disorder in daily life has increased dramatically because the thermal environment has been deteriorating. The main objective of this study was to examine regional differences in the relationship between heat disorder incidence rate and heat stress indices at Yamanashi Prefecture, Japan. Daily maximum air temperature and daily maximum WBGT were used as heat stress indices in each region. Nonlinear regression analysis was used to examine the regional difference in the relationship between the heat disorder incidence rate and heat stress indices in each region. The heat disorder incidence rate was correlated with both indices of heat stress in all regions. However, the more appropriate heat stress index for heat disorder prevention differed among regions. The distributions of heat stress indices, such as the slope of regression curve and the temperature threshold, differed in each region, irrespective of the index used. Therefore, the criteria for thermal conditions for heat disorder prevention need to be determined for each region, considering the regional characteristics of the relationship between the heat disorder incidence rate and heat stress indices.

scholarly journals 56 Impact of Electronically-Controlled Cooling Pads on Physiological Signs of Heat Stress in Early Lactation Sows

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 152-153
Author(s):  
Flannery J Whitmore ◽  
Allan P Schinckel ◽  
Robert Stwalley ◽  
Tyler Field ◽  
Morgan Burgett ◽  
...  
Keyword(s):  
Heat Stress ◽  
Feed Intake ◽  
Day Treatment ◽  
Time Of Day ◽  
Early Lactation ◽  
Controlled Cooling ◽  
Study Objective ◽  
Time Parity ◽  
The Difference ◽  
The Impact

Abstract The study objective was to evaluate the impact of electronically controlled cooling pads on physiological measurements of heat stress during early lactation. Twelve sows (d 3 to 11 of lactation) were provided with a specially designed cooling pad. Sows randomly received no cooling (CONTROL, n=6) or pads set to flush 2L cool water every 30s when aluminum plate reached 29.5°C (TREAT, n=6). Respiration rates (RR), rectal temperatures (RT) and skin temperatures (ST, 15 cm posterior to the ear) were recorded daily (0700 and 1500 h) for seven days of early lactation. Feed intake (DFI) was measured daily at 0700 h. RR, RT, and ST were fitted to a model that included the effects of day, time, parity, cooling pad treatment, and interactions. DFI was fitted to the same model, excluding time of day. For RR: treatment, day, time, treatment by day, treatment by time, and day by time interactions were significant (P&lt; 0.0004, CONTROL=49, TREAT= 30). Pad treatment had greater impact on RR during the first two days of the trial when the temperature was greater (32°C maximum CONTROL mean=66 vs. TREAT mean=30) than the following five days: 42, and 30 respectively). There was greater treatment impact on RR at 1500 versus 0700 h (0700 h: CONTROL= 35, TREAT= 25; 1500 h: CONTROL= 61, TREAT= 36). For RT: treatment, day, time, parity and interaction of day by time were significant (P&lt; 0.01, CONTROL= 37, treat= 35.). For ST: treatment, day, time, parity and the interactions of time by parity, treatment by time, and day by time were significant (P&lt; 0.0006, mean CONTROL=36.5, TREAT= 35.1). For DFI: day and the interaction of day by treatment were significant. The difference in feed intake between treatments increased as day increased. The use of electronically controlled cooling pads reduced measures of heat stress in early lactating sows.

Spatiotemporal distribution of foraging in a marine predator: behavioural drivers of hotspot formation

2020 ◽  
Vol 635 ◽  
pp. 187-202
Author(s):  
T Brough ◽  
W Rayment ◽  
E Slooten ◽  
S Dawson
Keyword(s):  
Time Of Day ◽  
Spatiotemporal Distribution ◽  
Temporal Effects ◽  
Marine Predator ◽  
Marine Predators ◽  
Additive Mixed Models ◽  
Density Analysis ◽  
The Times ◽  
Passive Acoustic ◽  
Spatial Locations

Many species of marine predators display defined hotspots in their distribution, although the reasons why this happens are not well understood in some species. Understanding whether hotspots are used for certain behaviours provides insights into the importance of these areas for the predators’ ecology and population viability. In this study, we investigated the spatiotemporal distribution of foraging behaviour in Hector’s dolphin Cephalorhynchus hectori, a small, endangered species from New Zealand. Passive acoustic monitoring of foraging ‘buzzes’ was carried out at 4 hotspots and 6 lower-use, ‘reference areas’, chosen randomly based on a previous density analysis of visual sightings. The distribution of buzzes was modelled among spatial locations and on 3 temporal scales (season, time of day, tidal state) with generalised additive mixed models using 82000 h of monitoring data. Foraging rates were significantly influenced by all 3 temporal effects, with substantial variation in the importance and nature of each effect among locations. The complexity of the temporal effects on foraging is likely due to the patchy nature of prey distributions and shows how foraging is highly variable at fine scales. Foraging rates were highest at the hotspots, suggesting that feeding opportunities shape fine-scale distribution in Hector’s dolphin. Foraging can be disrupted by anthropogenic influences. Thus, information from this study can be used to manage threats to this vital behaviour in the locations and at the times where it is most prevalent.

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