Effect of solar radiation on the heat load of dairy heifers.

1994 ◽  
Vol 45 (8) ◽  
pp. 1741 ◽  
Author(s):  
S Yamamoto ◽  
BA Young ◽  
BP Purwanto ◽  
F Nakamasu ◽  
T Matsumoto
Keyword(s):  
Heart Rate ◽  
Solar Radiation ◽  
Heat Load ◽  
Skin Surface ◽  
Skin Surface Temperature ◽  
Summer Period ◽  
Mean Body Temperature ◽  
Dairy Heifers ◽  
Globe Temperature ◽  
Black Globe Temperature

Thermoregulatory responses of Holstein heifers were studied under direct solar radiation and shade conditions during summer and autumn periods in southern Japan. The data were used to predict the contribution to effective temperature (ET) of solar radiation. The amount of solar radiation, including both direct and indirect sources, was estimated from black globe temperature (GT). There was no effect of solar radiation on the rate of heat production nor heart rate of the heifers. Rectal temperature increased significantly under no shade conditions during the summer period. Respiration rate (RR) and mean skin surface temperature paralleled changes in dry bulb temperature (DBT) and GT. The ET in the test situations, using RR and mean body temperature (Tb) as physiological indices, was predicted as: ET(DBT, GT) = 0.24DBT + 0 76GT. This equation indicates that solar radiation as measured by black globe temperature contributes substantially more to the heat load on animals than does dry bulb temperature.

Effect of heat load and dietary protein on oxygen pulse and energy cost for locomotion in heifers

2019 ◽  
Vol 59 (9) ◽  
pp. 1611
Author(s):  
E. E. L. Valente ◽  
V. T. Filipini ◽  
L. C. Araújo ◽  
M. Stahlhofer ◽  
B. V. R. Melo ◽  
...  
Keyword(s):  
Heart Rate ◽  
Energy Expenditure ◽  
Dietary Protein ◽  
Energy Cost ◽  
Heat Load ◽  
Protein Concentration ◽  
Oxygen Pulse ◽  
Humidity Index ◽  
Globe Temperature ◽  
Black Globe Temperature

The objectives of the present study were to evaluate the effect of heat load, bodyweight and dietary protein on oxygen pulse of heifers, to obtain the energy cost of walking on flat and sloping terrain, and to compare the energy cost of heifers during continuous walking and intermittent walking. In Experiment 1, the correlations of oxygen consumption, heart rate and oxygen pulse (O2P) with bodyweight, black globe temperature and temperature and humidity index were examined. Moreover, the effect of dietary protein on O2P was evaluated. The temperature and humidity index and black globe temperature had a low positive correlation with O2P and oxygen consumption, and a low negative correlation with heart rate. However, weight had no correlation with O2P. There was a linear increase in O2P with a very low adjustment with an increasing dietary crude protein concentration. In Experiment 2, the energy cost of heifers walking continuously at a constant speed in a terrain with 0%, 6% and 12% gradient was measured. The energy expenditure was similar among the terrain gradients. The heifers walking had a 16.6% higher energy expenditure than when they were standing. In Experiment 3, a comparison of the energy cost was made among heifers standing, continuously walking and intermittently walking at a constant speed on flat ground. The energy cost for walking was similar between continuous and intermittent walking. The heat load, bodyweight and dietary protein concentration had a low effect on O2P in dairy heifers. Therefore, measurements over a short time (5–15 min) are a reliable estimator of O2P through the day. Both intermittent and continuous walking can be used to evaluate energy expenditure.

scholarly journals Microclimate in silvipastoral systems with eucalyptus in rank with different heights

2010 ◽  
Vol 39 (3) ◽  
pp. 685-694 ◽  
Author(s):  
Wander de Souza ◽  
Orlando Rus Barbosa ◽  
Jair de Araújo Marques ◽  
Marco Aurélio Teixeira Costa ◽  
Eliane Gasparino ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Thermal Load ◽  
Heat Load ◽  
Temperature Humidity Index ◽  
Heat Load Index ◽  
Humidity Index ◽  
Globe Temperature ◽  
Black Globe Temperature

The aim of this work was to verify if the presence of trees and its height in formed silvipastoral systems with eucalyptus planted in rank can modify the microclimate and improve the environment for bovine raising during the day in summer. It was evaluated the microclimate of the environment in formed silvipastoral systems in rank of eucalyptus with 8 m, 18 m and 28 meters of height, compared to a system no shade in the summer. The experimental design was a split plot with six hour time in sub parcels. The systems are made up of parcels and the months as block in four replications and the interaction hour × system. The air temperature, black globe temperature, relative humidity and wind speed were observed to create the following indexes for thermal comfort: temperature-humidity index; black globe-humidity index; heat load index and the radiant thermal load. Excepted for the relative humidity, there was interaction for time × system for all variables and indexes. Interaction occurred for: air temperature at 10 a.m. and 6 p.m.; wind speed from 8 a.m. to 4 p.m.; temperature humidity index at 10 a.m. and 12 p.m.; black globe temperature, black globe humidity index, heat load index, and radiant thermal load at all the hours. During the summer, the system with shade of 28 m trees had the lowest average of black globe temperature; wind speed; black globe humidity index; radiant thermal load index; and heat load index. There was a reduction of wind speed average in systems 8 m, 18 m and 28 m trees in, respectively, 20.7; 50.0 and 48.0% in relation to no shade system; however it was not proportional to the height, with influence of the rank porosity and pantries height. Nevertheless, for radiant thermal load index the reduction was proportional to the height of the trees with 10.24; 12.49 and 20.76%, respectively, for 8 m, 18 m and 28 meters of height. There was a reduction of the thermal stress in the environment due to the presence of trees, being the heat load index thermal the index that better demonstrated the effect, despite of not being proportional to the rank height.

scholarly journals The Effects of Metabolic Work Rate and Ambient Environment on Physiological Tolerance Times While Wearing Explosive and Chemical Personal Protective Equipment

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Joseph T. Costello ◽  
Kelly L. Stewart ◽  
Ian B. Stewart
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Personal Protective Equipment ◽  
Limiting Factor ◽  
Protective Equipment ◽  
Mean Body Temperature ◽  
Wet Bulb Globe Temperature ◽  
Physiological Tolerance ◽  
Volitional Fatigue ◽  
Globe Temperature

This study evaluated the physiological tolerance times when wearing explosive and chemical (>35 kg) personal protective equipment (PPE) in simulated environmental extremes across a range of differing work intensities. Twelve healthy males undertook nine trials which involved walking on a treadmill at 2.5, 4, and 5.5 km·h−1in the following environmental conditions, 21, 30, and 37°C wet bulb globe temperature (WBGT). Participants exercised for 60 min or until volitional fatigue, core temperature reached 39°C, or heart rate exceeded 90% of maximum. Tolerance time, core temperature, skin temperature, mean body temperature, heart rate, and body mass loss were measured. Exercise time was reduced in the higher WBGT environments (WBGT37 < WBGT30 < WBGT21;P< 0.05) and work intensities (5.5 < 4 < 2.5 km·h−1;P< 0.001). The majority of trials (85/108; 78.7%) were terminated due to participant’s heart rate exceeding 90% of their maximum. A total of eight trials (7.4%) lasted the full duration. Only nine (8.3%) trials were terminated due to volitional fatigue and six (5.6%) due to core temperatures in excess of 39°C. These results demonstrate that physiological tolerance times are influenced by the external environment and workload and that cardiovascular strain is the limiting factor to work tolerance when wearing this heavy multilayered PPE.

Developing a heat load index for lactating dairy cows

2018 ◽  
Vol 58 (8) ◽  
pp. 1387 ◽  
Author(s):  
J. C. Lees ◽  
A. M. Lees ◽  
J. B. Gaughan
Keyword(s):  
Logistic Regression ◽  
Wind Speed ◽  
Relative Humidity ◽  
Dairy Cows ◽  
Heat Load ◽  
Heat Load Index ◽  
Lactating Dairy Cows ◽  
Globe Temperature ◽  
Panting Score ◽  
Black Globe Temperature

The temperature humidity index (THI) has been extensively used in the Australian dairy industry as an indicator of heat load conditions. However, there are limitations to the THI, where it does not account for solar radiation or wind speed. In addition, the THI has not been formulated in conjunction with physiological data. Thus, it is not apparent whether the THI provides the best prediction for impact of heat load on lactating dairy cattle. The aim of the present study was to develop a dairy heat load index (DHLI), based on the physiological responses of lactating dairy cows to environmental conditions. The study was undertaken at The University of Queensland, Gatton Campus, Australia, over three summers and two winters. Observations were conducted four times daily at 0800 hours, 1200 hours, 1400 hours and 1700 hours. Weather data were obtained every 10 min from an onsite, automated weather station. Panting score data were used to calculate a mean panting score of the herd. Developing the DHLI encompassed three different modelling techniques, including (1) linear regression, (2) broken stick regression and (3) non-linear logistic regression. Comparisons between the models indicated there was an increase in accuracy when using non-linear logistic regression (R2 = 0.542). The DHLI model developed was based on mean panting score, black globe temperature (°C) and relative humidity. By utilising the black globe temperature, the DHLI is able to incorporate the combined effects of ambient temperature, relative humidity, solar radiation and wind speed in a single unit measure. By combining climatic conditions and a physiological response, i.e. panting score, the DHLI model may become a more accurate prediction of heat load for lactating dairy cows. The DHLI produces a unit value between 0 and 100. When DHLI is 0, there would be no panting and, when DHLI is 100, all cows within the herd would be panting.

Assessment of heat stress in a hot environment using the WBGTeff index according to the standard PN-EN ISO 7243:2018-01

2021 ◽  
Vol XXXVII (1) ◽  
pp. 5-15
Author(s):  
Magdalena Młynarczyk ◽  
Maria kONARSKA
Keyword(s):  
Heat Load ◽  
Occupational Safety ◽  
Occupational Safety And Health ◽  
Environmental Engineering ◽  
Metabolic Heat ◽  
Hot Environment ◽  
Safety And Health ◽  
Globe Temperature ◽  
Two Parameters ◽  
Black Globe Temperature

The assessment of maximum allowable heat load of a body in a hot environment is determined using the WBGT index. The name of the WBGT index is derived from the measurement of two parameters: natural wet-bulb temperature and black globe temperature. WBGT as an indicator used to assess the heat load (until 2017) was related to the metabolic heat production and placed in the form of tables in the Polish edition of Standard No.PN-EN 27243:2005 (and PN-EN 27243:2005P). In 2017, this standard was replaced by Standard No. EN ISO 7243:2017, and in January 2018, the Polish translation of Standard No. PN-EN ISO 7243:2018-01 was approved. This article describes the methodology of conducting WBGT research according to Standard No. PN-EN ISO 7243:2018-01. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Effect of season on thermoregulatory responses and energy expenditure of goats on semi-arid range in India

2002 ◽  
Vol 139 (1) ◽  
pp. 87-93 ◽  
Author(s):  
A. K. SHINDE ◽  
RAGHAVENDRA BHATTA ◽  
S. K. SANKHYAN ◽  
D. L. VERMA
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Solar Radiation ◽  
Energy Expenditure ◽  
Arid Regions ◽  
Physiological Responses ◽  
Face Mask ◽  
Mean Value ◽  
The Mean ◽  
Semi Arid

A study of the physiological responses and energy expenditure of goats was carried out from June 1999 to May 2000 by conducting two experiments: one on bucks maintained on stall feeding in autumn 1999 (Expt 1) followed by year-round grazing on native ranges over three seasons: monsoon, winter and summer (Expt 2). Physiological responses and energy expenditure (EE) measurements of housed and grazing goats were recorded at 06.00 h and 14.00 h for 5 consecutive days in each season. Goats were fixed with a face mask and meteorological balloon for collection of expired air and measurement of EE. Respiration rate (RR) at 06.00 h was similar in all seasons (14 respiration/min) except in the monsoon, where a significantly (P<0.05) higher value (26 respiration/min) was recorded. At 14.00 h, RR was higher in monsoon and summer (81 and 91 respiration/min) than in winter (52 respiration/min). Irrespective of the season, heart rate (HR) was higher at 14.00 h (86 beat/min) than at 06.00 h (64 beat/min). The rise of rectal temperature (RT) from morning (06.00 h) to peak daily temperature (14.00 h) was 0.9 °C in housed goats in autumn and 1.0, 2.1 and 2.0 °C in grazing goats during monsoon, winter and summer, respectively. The mean value was 1.7 °C. Skin temperature (ST) was lowest in winter (30.1 °C) and highest at 14.00 h in summer (40.3 °C). Energy expenditure of goats at 06.00 h was 32.7 W in winter and significantly (P<0.05) increased to 52.0 W in summer and 107.8 W in monsoon. At 14.00 h, EE was 140.2 W in winter and increased to 389.0 W and 391.3 W respectively in monsoon and summer. It is concluded that monsoon and summer are both stressful seasons in semi-arid regions. Animals should be protected from direct solar radiation during the hottest hours of the day to ameliorate the effect of heat stress.

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