Evaluation of Thermal Indices as the Indicators of Heat Stress in Dairy Cows in a Temperate Climate

Many thermal indices (TIs) have been developed to quantify the severity of heat stress in dairy cows. Systematic evaluation of the representative TIs is still lacking, which may cause potential misapplication. The objectives of this study were to evaluate the theoretical and actual performance of the TIs in a temperate climate. The data were collected in freestall barns at a commercial dairy farm. The heat transfer characteristics of the TIs were examined by equivalent air temperature change (ΔTeq). One-way ANOVA and correlation were used to test the relationships between the TIs and the animal-based indicators (i.e., rectal temperature (RT), respiration rate (RR), skin temperature (ST), and eye temperature (ET)). Results showed that the warming effect of the increased relative humidity and the chilling effect of the increased wind speed was the most reflected by the equivalent temperature index (ETI) and the comprehensive climate index (CCI), respectively. Only the equivalent temperature index for cows (ETIC) reflected that warming effect of solar radiation could obviously increase with increasing Ta. The THI and ETIC showed expected relationships with the RT and RR, whereas the CCI and ETIC showed expected relationships with the ST and ET. Moreover, CCI showed a higher correlation with RT (r = 0.672, p < 0.01), ST(r = 0.845, p < 0.01), and ET (r = 0.617, p < 0.01) than other TIs (p < 0.0001). ETIC showed the highest correlation with RR (r = 0.850, p < 0.01). These findings demonstrated that the CCI could be the most promising thermal index to assess heat stress for housed dairy cows. Future research is still needed to develop new TIs tp precisely assess the microclimates in cow buildings.

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Modeling of Heat Stress in Sows—Part 1: Establishment of the Prediction Model for the Equivalent Temperature Index of the Sows

Animals ◽

10.3390/ani11051472 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1472

Author(s):

Mengbing Cao ◽

Chao Zong ◽

Xiaoshuai Wang ◽

Guanghui Teng ◽

Yanrong Zhuang ◽

...

Keyword(s):

Heat Stress ◽

Relative Humidity ◽

Skin Temperature ◽

Air Temperature ◽

Physiological Response ◽

Equivalent Temperature ◽

Air Velocity ◽

Thermal Indices ◽

Thermal Index ◽

Temperature Index

Heat stress affects the estrus time and conception rate of sows. Compared with other life stages of pigs, sows are more susceptible to heat stress because of their increased heat production. Various indicators can be found in the literature assessing the level of heat stress in pigs. However, none of them is specific to assess the sows’ thermal condition. Moreover, thermal indices are mainly developed by considering partial environment parameters, and there is no interaction between the index and the animal’s physiological response. Therefore, this study aims to develop a thermal index specified for sows, called equivalent temperature index for sows (ETIS), which includes parameters of air temperature, relative humidity and air velocity. Based on the heat transfer characteristics of sows, multiple regression analysis is used to combine air temperature, relative humidity and air velocity. Environmental data are used as independent variables, and physiological parameters are used as dependent variables. In 1029 sets of data, 70% of the data is used as the training set, and 30% of the data is used as the test set to create and develop a new thermal index. According to the correlation equation between ETIS and temperature-humidity index (THI), combined with the threshold of THI, ETIS was divided into thresholds. The results show that the ETIS heat stress threshold is classified as follows: suitable temperature ETIS < 33.1 °C, mild temperature 33.1 °C ≤ ETIS < 34.5 °C, moderate stress temperature 34.5 °C ≤ ETIS < 35.9 °C, and severe temperature ETIS ≥ 35.9 °C. The ETIS model can predict the sows’ physiological response in a good manner. The correlation coefficients R of skin temperature was 0.82. Compared to early developed thermal indices, ETIS has the best predictive effect on skin temperature. This index could be a useful tool for assessing the thermal environment to ensure thermal comfort for sows.

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Use of the Comprehensive Climate Index to estimate heat stress response of grazing dairy cows in a temperate climate region

Journal of Dairy Research ◽

10.1017/s0022029921000406 ◽

2021 ◽

pp. 1-8

Author(s):

Rodrigo A. Arias ◽

Cynthia Delgado ◽

Juan Pablo Keim ◽

Mónica Gandarillas

Keyword(s):

Heat Stress ◽

Dairy Cows ◽

Milk Production ◽

Thermal Condition ◽

Time Of Day ◽

Temperate Climate ◽

Climate Index ◽

Climate Region ◽

Stage Of Lactation ◽

Grazing Dairy Cows

Abstract The aim of the study was to assess the effect of the summer thermal environment on physiological responses, behaviour, milk production and its composition on grazing dairy cows in a temperate climate region, according to the stage of lactation. Twenty-nine Holstein Friesian multiparous cows were randomly selected and divided into two groups, according to the days in milk, as mid-lactation (99 to 170 d in milk, n = 15) and late lactation (225 to 311 d in milk, n = 14). The comprehensive climate index (CCI) was used to classify the hour of each day as thermoneutral or heat stress, considering a threshold value of CCI of 20°C. Data were collected for 16 d (summer 2017) and analysed as a completely randomized 2 × 2 factorial arrangement with repeated measurements over time. Vaginal temperature increased with CCI ≥ 20°C. Respiration rates were dependent on the thermal condition, regardless of days in milk. There was an interaction between the time of day and the CCI category for activity and rumination. Grazing activity decreased by 17.6% but lying down, standing, and shaded animals increased by 1.6, 9.8, and 6.3% respectively when CCI ≥ 20°C. Over 80% of cows presented a panting score ≥1. However, milk production and composition (fat, protein, and lactose concentrations as well as somatic cell count) were not affected by the thermal condition, although there was a numerical (non-significant) decrease in afternoon milk protein concentration on days with CCI ≥ 20°C, while urea in milk increased. In conclusion, thermal condition challenged grazing dairy cows' behaviour and physiology independent of the stage of lactation but had little or no effect on milk production.

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Comparison of Thermal Comfort between Sapporo and Tokyo—The Case of the Olympics 2020

Atmosphere ◽

10.3390/atmos11050444 ◽

2020 ◽

Vol 11 (5) ◽

pp. 444

Author(s):

Yuting Wu ◽

Kathrin Graw ◽

Andreas Matzarakis

Keyword(s):

Heat Stress ◽

Thermal Comfort ◽

Olympic Games ◽

Physiologically Equivalent Temperature ◽

Precipitation Rate ◽

Equivalent Temperature ◽

Thermal Indices ◽

Climate Conditions ◽

Northern City ◽

The Olympic Games

Weather and climate conditions can be decisive regarding travel plans or outdoor events, especially for sport events. The Olympic Games 2020, postponed to 2021, will take place in Tokyo at a time which is considered to be the hottest and most humid time of the year. However, a part of the athletic competitions is relocated to the northern city Sapporo. Therefore, it is important to quantify thermal comfort for different occasions and destinations and make the results accessible to visitors and sport attendees. The following analysis will quantify and compare thermal comfort and heat stress between Sapporo and Tokyo using thermal indices like the Physiologically Equivalent Temperature and the modified Physiologically Equivalent Temperature (PET and mPET). The results reveal different precipitation patterns for the cities. While a higher precipitation rate appears in Sapporo during winter, the precipitation rate is higher in Tokyo during summer. PET and mPET exhibit a greater probability of heat stress conditions in Tokyo during the Olympic Games, whereas Sapporo has more moderate values for the same period. The Climate-Tourism/Transfer-Information-Scheme (CTIS) integrates and simplifies climate information and makes them comprehensible for non-specialists. The CTIS of Tokyo illustrates lower suitable conditions for “Heat stress”, “Sunny days” and “Sultriness”. Transferring parts of the athletics competition to a northern city is thus more convenient for athletes, staff members and spectators. Hence, heat stress can be avoided and an acceptable outdoor stay is ensured. Overall, this quantification and comparison of the thermal conditions in Sapporo and Tokyo reveal limitations but also possibilities for the organizers of the Olympic Games. Furthermore it can be used to raise awareness for promoting or arranging countermeasures and heat mitigation at specific events and destinations, if necessary.

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PSX-B-27 Physiological changes in grazing dairy cows at increasing temperatures under moderate climate conditions

Journal of Animal Science ◽

10.1093/jas/skab235.495 ◽

2021 ◽

Vol 99 (Supplement_3) ◽

pp. 270-270

Author(s):

Alice Pontiggia ◽

Andreas Münger ◽

Lukas Eggerschwiler ◽

Dimitri Stucki ◽

Stefanie Ammer ◽

...

Keyword(s):

Heat Stress ◽

Dairy Cows ◽

Climate Index ◽

Full Time ◽

Climate Conditions ◽

Physiological Indicators ◽

Direct Exposure ◽

Grazing Dairy Cows ◽

Vaginal Temperature ◽

Moderate Climate

Abstract The continuous direct exposure to solar radiation, coupled with their own metabolic heat production, make grazing dairy cows on pasture particularly susceptible to heat stress. Heat stress can impair performance, animal welfare, and health. The objective of the present study was to identify physiological indicators of heat stress in dairy cows in a pasture-based production system under moderate climate conditions. The study was performed with 24 lactating Holstein dairy cows during summer 2018 and 2019 at the experimental farm of Agroscope (Posieux, Switzerland). Cows grazed full-time using a set stocking system. Climate conditions were recorded every min and were used to calculate the comprehensive climate index (CCI), which reflects the felt temperature in °C. The vaginal temperature (VT) of each cow was measured every 10 minutes with temperature loggers and was used as a physiological indicator of heat stress. Blood and milk were sampled once daily in the afternoon before and during milking, respectively. The concentrations of thyroxine (T4) and triiodothyronine (T3) were analyzed in blood plasma and cortisol concentration was analyzed in milk. Data from 12 periods of up to 3 consecutive days with increasing CCI was analyzed. Analysis were performed with the averaged CCI and the maximal VT recorded between 0830 and 1430 h. The VTmax was positively correlated with CCIaverage (P < 0.001). The T4 and T3 concentrations decreased with increasing CCIaverage and VTmax (P < 0.01). Cortisol concentrations were positively correlated with CCIaverage and VTmax (P < 0.05). Changes in VT and hormones showed that cows responded to increasing environmental temperature and may have perceived the rising heat load as a stressor.

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Is Physiological Equivalent Temperature (PET) a superior screening tool for heat stress risk than Wet-Bulb Globe Temperature (WBGT) index? Eight years of data from the Gothenburg half marathon

British Journal of Sports Medicine ◽

10.1136/bjsports-2019-100632 ◽

2020 ◽

pp. bjsports-2019-100632 ◽

Cited By ~ 1

Author(s):

Sofia Thorsson ◽

David Rayner ◽

Gunnar Palm ◽

Fredrik Lindberg ◽

Eric Carlström ◽

...

Keyword(s):

Heat Stress ◽

Screening Tool ◽

Radiant Heat ◽

Climate Index ◽

Sporting Events ◽

Equivalent Temperature ◽

Physiological Equivalent Temperature ◽

Wet Bulb Globe Temperature ◽

Globe Temperature ◽

Pet Index

BackgroundThe Wet-Bulb Globe Temperature (WBGT) index is a common tool to screen for heat stress for sporting events. However, the index has a number of limitations. Rational indices, such as the physiological equivalent temperature (PET) and Universal Thermal Climate Index (UTCI), are potential alternatives.AimTo identify the thermal index that best predicts ambulance-required assistances and collapses during a city half marathon.MethodsEight years (2010–2017) of meteorological and ambulance transport data, including medical records, from Gothenburg’s half-marathon were used to analyse associations between WBGT, PET and UTCI and the rates of ambulance-required assistances and collapses. All associations were evaluated by Monte-Carlo simulations and leave-one-out-cross-validation.ResultsThe PET index showed the strongest correlation with both the rate of ambulance-required assistances (R2=0.72, p=0.008) and collapses (R2=0.71, p=0.008), followed by the UTCI (R2=0.64, p=0.017; R2=0.64, p=0.017) whereas the WBGT index showed substantially poorer correlations (R2=0.56, p=0.031; R2=0.56, p=0.033). PET stages of stress, match the rates of collapses better that the WBGT flag colour warning. Compared with the PET, the WBGT underestimates heat stress, especially at high radiant heat load. The rate of collapses increases with increasing heat stress; large increase from the day before the race seems to have an impact of the rate of collapses.ConclusionWe contend that the PET is a better predictor of collapses during a half marathon than the WBGT. We call for further investigation of PET as a screening tool alongside WBGT.

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Responses of dairy cows to short-term heat stress in controlled-climate chambers

Animal Production Science ◽

10.1071/an16472 ◽

2017 ◽

Vol 57 (7) ◽

pp. 1233 ◽

Cited By ~ 21

Author(s):

J. B. Garner ◽

M. Douglas ◽

S. R. O. Williams ◽

W. J. Wales ◽

L. C. Marett ◽

...

Keyword(s):

Heat Stress ◽

Dairy Cows ◽

Milk Yield ◽

Dry Matter ◽

Experimental Period ◽

Dry Matter Intake ◽

Temperate Climate ◽

Short Term ◽

Temperature And Humidity ◽

Humidity Index

The objective of the present research was to describe the physiological and production responses of lactating dairy cows during and after sudden exposure to temperate-climate heat-wave conditions, compared with cows in thermoneutral conditions. Twelve lactating multiparous Holstein–Friesian dairy cows were housed in controlled-climate chambers for 4 days. Six were exposed to a short-term temperature and humidity challenge (THc, diurnal temperature and humidity fluctuations inducing moderate heat stress; temperature humidity index 74–84) and six cows were exposed to thermoneutral conditions (THn, temperatur humidity index 55–61). Cows were also measured during a 7-day pre-experimental and 14-day post-experimental period. Physiological indicators of heat stress were measured, including rectal and vaginal temperature and respiration rate, which indicated that the THc in controlled-climate chambers induced moderate heat stress. The cows exposed to the 4-day THc reduced their milk yield by 53% and their dry-matter intake by 48%, compared with the cows in the THn treatment. Milk yield of THc cows returned to pre-experimental milk yield by Day 7 and dry-matter intake by Day 4 of the post-experimental period. The short-term heat challenge induced metabolic adaptations by mobilising adipose tissue, as indicated by increased non-esterified fatty acids, and amino acids from skeletal muscle, as indicated by increased urea nitrogen to compensate for reduced nutrient intake and increased energy expenditure. Endocrine responses included greater prolactin concentrations, which is associated with thermoregulation and water metabolism. The cows exposed to THc displayed production and physical responses that facilitated lower metabolic heat production and greater heat dissipation in an attempt to maintain homeostasis during the short-term heat exposure. These results indicated that the conditions imposed on the cows in the controlled-climate chambers were sufficient to induce heat-stress responses and adversely affected production in the lactating dairy cow, and the delay between the return to normal feed intake and milk yield following the heat challenge suggests a period of metabolic recovery was occurring.

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Modeling of Heat Stress in Sows Part 2: Comparison of Various Thermal Comfort Indices

Animals ◽

10.3390/ani11061498 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1498

Author(s):

Mengbing Cao ◽

Chao Zong ◽

Yanrong Zhuang ◽

Guanghui Teng ◽

Shengnan Zhou ◽

...

Keyword(s):

Heat Stress ◽

Thermal Environment ◽

Production Performance ◽

Heat Index ◽

Growth Stages ◽

Equivalent Temperature ◽

Thermal Indices ◽

Important Indicator ◽

Thermal Index ◽

Heat Indices

Heat stress has an adverse effect on the production performance of sows, and causes a large economic loss every year. The thermal environment index is an important indicator for evaluating the level of heat stress in animals. Many thermal indices have been used to analyze the environment of the pig house, including temperature and humidity index (THI), effective temperature (ET), equivalent temperature index of sows (ETIS), and enthalpy (H), among others. Different heat indices have different characteristics, and it is necessary to analyze and compare the characteristics of heat indices to select a relatively suitable heat index for specific application. This article reviews the thermal environment indices used in the process of sow breeding, and compares various heat indices in four ways: (1) Holding the value of the thermal index constant and analyzing the equivalent temperature changes caused by the relative humidity. (2) Analyzing the variations of ET and ETIS caused by changes in air velocity. (3) Conducting a comparative analysis of a variety of isothermal lines fitted to the psychrometric chart. (4) Analyzing the distributions of various heat index values inside the sow barn and the correlation between various heat indices and sow heat dissipation with the use of computational fluid dynamics (CFD) technology. The results show that the ETIS performs better than other thermal indices in the analysis of sows’ thermal environment, followed by THI2, THI4, and THI7. Different pigs have different heat transfer characteristics and different adaptability to the environment. Therefore, based on the above results, the following suggestions have been given: The thermal index thresholds need to be divided based on the adaptability of pigs to the environment at different growth stages and the different climates in different regions. An appropriate threshold for a thermal index can provide a theoretical basis for the environmental control of the pig house.

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Development and Validation of an Autonomous Radio-Frequency Identification Controlled Soaking System for Dairy Cattle

Applied Engineering in Agriculture ◽

10.13031/aea.14344 ◽

2021 ◽

Vol 37 (5) ◽

pp. 831-837

Author(s):

Gustavo Mazon ◽

Patrick D Montgomery ◽

Morgan Hayes ◽

Joshua Jackson ◽

Joao H. C. Costa

Keyword(s):

Heat Stress ◽

Dairy Cattle ◽

Dairy Cows ◽

Radio Frequency Identification ◽

Raspberry Pi ◽

Future Research ◽

Uhf Rfid ◽

Frequency Identification ◽

The Right ◽

Very High

HighlightsThe high variation on how dairy cows experience heat stress opens the space for individual heat abatement options.We developed an UHF-RFID activated soaking system for dairy cattle and validated it statically and dynamically.Percentage of soaker activations was moderate when validated statically and very high when validated dynamically.Future research should validate the system using dairy cows and evaluate effects on physiology and behavior.Abstract. This study aim was to develop and validate a radio-frequency identification (RFID) controlled cattle soaking system for use in dairy cattle. The autonomous system was composed of a Raspberry Pi microcontroller, an ultra-high frequency (UHF) RFID system, a temperature-humidity sensor, and a water soaker. The system was developed and programmed to identify and tailor heat stress abatement to dairy cattle. The validation of the system was divided into static and dynamic phases. During the static phase, five UHF-RFID tags were statically placed 5 times in 11 points of interest on a ranging from 0 to 150 cm of the antenna. During the dynamic phase, 10 tags were moved 10 times each from 150 cm to the right (closer to the barn) to 150 cm to the left (further from the barn) of the center of the antenna mimicking a cow’s walking speed. During the static validation, the percentage of successful readings was moderate (MEAN±SD; 77.8±30.1%). We found that the distance from the antenna affected the percentage of successful readings (P<0.01), it was 100% up to 60 cm from the antenna and static readings were less successful from 120 cm left up to 90 cm to the right of the center of the antenna. During the dynamic validation, the percentage of successful readings was very high (96.0±7.0%). These results suggest that the autonomous soaker system seems to be able to detect cows in movement underneath the system. Future research should validate the system using live dairy cows. Keywords: Automation, Heat stress, Raspberry Pi, RFID.

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Evaluation of thermal stress indexes for dairy cows in tropical regions

Revista Brasileira de Zootecnia ◽

10.1590/s1516-35982007000500028 ◽

2007 ◽

Vol 36 (4 suppl) ◽

pp. 1192-1198 ◽

Cited By ~ 36

Author(s):

Roberto Gomes da Silva ◽

Débora Andréa Evangelista Façanha Morais ◽

Magda Maria Guilhermino

Keyword(s):

Dairy Cows ◽

Heat Load ◽

Selection Criterion ◽

Equivalent Temperature ◽

Temperature Index ◽

Tropical Regions ◽

Heat Load Index ◽

Humidity Index ◽

Index Value ◽

Jersey Cows

Data from 359 Holstein and 54 Jersey cows (total of 1359 observations) collected in commercial herds in the northeast of Brazil were used to evaluate six environmental stress indexes. The selection criterion was the correlation between the index value with the rectal temperature (RT) and the respiratory rate (RR) of cows. Both Temperature-Humidity Index (THI) and Black Globe-Humidity Index (BGHI) had the lowest correlations with animal RT and RR. The selected indexes were the Equivalent Temperature Index (r = 0.293 and 0.520 with RT and RR, respectively) and the Heat Load Index (0.286 and 0.542, respectively).

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Most Appropriate Heat Stress Index for Half-blood Dairy Heifers

Acta Scientiae Veterinariae ◽

10.22456/1679-9216.80577 ◽

2017 ◽

Vol 45 (1) ◽

pp. 8 ◽

Cited By ~ 1

Author(s):

Patrícia Kelly de Moraes Brettas ◽

Mara Regina Bueno de Mattos Nascimento ◽

Ednaldo Carvalo Guimarães ◽

Gabriella Pereira Souza

Keyword(s):

Heat Stress ◽

Wind Speed ◽

Respiratory Rate ◽

Stress Index ◽

Equivalent Temperature ◽

Temperature Index ◽

Dairy Heifers ◽

Physiological Variables ◽

Heat Stress Index ◽

Radiant Temperature

Background: Heat stress indexes integrate several variables of the thermal environment in a single figure and predict their impact on animal welfare and performance. The correct interpretation of these indexes is of help in the choice of more adequate measures to attenuate the stress caused by the heat. Therefore, the aim of this research is to examine some of the heat stress indexes mentioned in the literature and to decide which ones best reflect the potential impact of meteorological conditions on the thermal homeostasis of half-blood dairy heifers bred in Uberlândia, Triângulo Mineiro area, Minas Gerais, Brazil.Materials, Methods & Results: Eight half-blood dairy heifers were exposed to direct sunlight from 9 h to 13 h in the months of November and December of 2016, and also January and February of 2017, 5 days per month on average, in Uberlândia, MG, Brazil. After this challenge, the respiratory rate and the rectal temperature were measured. Simultaneously to the collection of physiological variables, the temperatures of dry bulb and wet bulb, as well as that of black globe, were quantified, as was the wind speed. Afterwards, the solar radiation, the relative humidity, the mean radiant temperature and some heat stress indexes were calculated, the latter being Temperature-Humidity Index, Black Globe-Humidity Index, Equivalent Temperature Index, Environmental Stress Index, Respiratory Rate Index, Thermal Load Index, Environmental Specification Index, Thermal Comfort Index for Dairy Cattle, Comprehensive Climate Index and Cattle Heat Stress Index. These indexes were, then, correlated with the physiological variables. The averages of room temperature, black globe temperature, solar radiation, wind speed, radiant temperature and relative humidity were, respectively, 29.96°C, 41.73°C, 831.02 W/m2, 0.11 m/s-1, 318.14 K and 50.51%. Rectal temperature averaged 38.8ºC while respiratory rate averaged 41.97 breaths per minute-1. Correlating the 10 heat stress indexes with these two physiological variables, it was verified that the highest values, with a confidence of 95%, were demonstrated by the Equivalent Temperature Index (0.200 and 0.317, respectively), followed by the Cattle Heat Stress Index (0.186 and 0.314, respectively).Discussion: Room temperature was within the thermoneutral zone for half-blood dairy cattle. Nevertheless, the mean radiant temperature and the black globe temperature were higher, due to intense solar radiation. Wind speed was not very expressive and relative humidity was close to what was required. The average values of rectal temperature and respiratory rate were normal, which indicated the heifers are adapted to the thermal environment. Regarding the heat stress indexes, the Equivalent Temperature Index was recommended, as it presented the highest amount of meaningful correlations with the physiological variables, followed by the Cattle Heat Stress Index and the Environmental Stress Index. The average value of the Equivalent Temperature Index remained in the “caution” category, according to the literature’s two existing scales for interpretation of said index’s results, indicating the occurrence of stress by heat, albeit not severe. In conclusion, the Equivalent Temperature Index is considered the most appropriate heat stress index for evaluating a heat stress situation in half-blood dairy heifers bred in Uberlândia, Triângulo Mineiro, followed by the Cattle Heat Stress Index and the Environmental Stress Index.

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