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Temperature-Humidity Index (THI) chart (based on Thom, 1959). Associated Livestock Weather Safety Index (LWSI; LCI, 1970) categories are also shown.  

Temperature-Humidity Index (THI) chart (based on Thom, 1959). Associated Livestock Weather Safety Index (LWSI; LCI, 1970) categories are also shown.  

Citations

... The climatic conditions during the experimental period are presented in Table 1. The experiments 1 and 2 were conducted under the alert (THI ranged from 75 to 78) and dangerous (THI ranged from 79 to 83) conditions of HS (Hahn et al. 2009). ...
Article
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Relatively, little is known about the corpus luteum (CL) function in early pregnancy after the successful treatment of luteal phase defciency in repeat-breeder dairy cows when exposed to extreme environments under tropical climate. To investigate the infuence of increased tissues of corpora lutea (CLs) by inducing secondary CL based on progesterone (P4) concentration and fertility in repeat-breeder dairy cows undergoing the fxed-time artifcial insemination (FTAI) protocol, 32 cows were treated with gonadotropin releasing hormone (GnRH) on day 5 post-induction (experiment 1). In experiment 2, 213 cows were bred using the short-term FTAI protocol. On day 5 post-FTAI, cows were divided into two groups: treatment with (GnRH5-treated group) or without (GnRH5-untreated group) GnRH. The temperature-humidity index ranged from 77.3 to 82.8. Cows bearing two CLs had greater P4 concentrations than cows bearing only one CL on their ovaries (P<0.05). Pregnancy rates were greater in GnRH5-treated group than the GnRH5-untreated group (P<0.01). Moreover, repeat-breeder cows bearing two CLs had a greater likelihood of pregnancy (odds ratio=20.86) than cows bearing only one CL on their ovaries (P<0.01). Under heat stress condition, the results highlighted that increasing luteal tissues by creating secondary CL leads to enhanced peripheral P4 concentrations and improved pregnancy outcomes in repeat-breeder dairy cows.
... Temperature humidity index (THI), which combines temperature and relative humidity, is often used in studies of heat stress (Dash et al. 2016). Many studies have shown the risk of reduced production and animal welfare due to heat stress in periods with high THI (reviewed by Hahn et al. 2009). In Sub-Saharan Africa, drought and dry seasons are becoming more frequent and longer in duration, resulting in heat stress for dairy cattle (Kekana et al. 2018). ...
Article
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Tropical regions are characterized by high temperature and humidity across the year. At high values of temperature humidity index (THI), there is a risk of heat stress leading to lower milk yield. The objective of this study was to describe the effect of season and the effect of maximum daily THI on milk yield of that day in purebred Ankole and Ankole-Friesian, Ankole-Jersey and Ankole-Sahiwal crosses in a tropical climate. In total, 53,730 records of daily milk yield from 183 cows in Rwanda were analyzed. The results showed that THI had a negative effect on daily milk yield above a threshold, but the effect was small (− 0.11 kg milk/THI unit at most). Purebred Ankole cows had the lowest daily milk yield and the lowest threshold (THI mean 66), as compared to the crossbreds (THI mean 68–69). Ankole-Friesian had a steeper decline in daily milk yield above the threshold than Ankole. The crossbreds, especially Ankole-Friesian, had higher daily milk yield than purebred Ankole also at very high THI. The results indicate some differences between breed groups in the way of coping with a hot and humid climate and raise questions about dairy cows’ adaptation to such a climate.
... Higher NEFA concentrations are associated with intense subcutaneous lipid mobilization (Vitali et al., 2009;Bernabucci et al., 2010;Cincović et al., 2011). NEFA is released into the bloodstream due to lipolysis and can act as an alternative source of energy (LeRoy Hahn et al., 2013). The mobilization of body fat, which can be used for energy or milk fat synthesis, may lead to the formation of ketone bodies such as acetoacetate, acetone, and betahydroxybutyrate (Drackley et al., 1991;Peterson et al., 2012;Tian et al., 2015). ...
Article
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Heat stress (HS) in dairy cows causes considerable losses in the dairy industry worldwide due to reduced animal performance, increased cases of metabolic disorders, altered rumen microbiome, and other health problems. Cows subjected to HS showed decreased ruminal pH and acetate concentration and an increased concentration of ruminal lactate. Heat-stressed cows have an increased abundance of lactate-producing bacteria such as Streptococcus and unclassified Enterobacteriaceae, and soluble carbohydrate utilizers such as Ruminobacter , Treponema , and unclassified Bacteroidaceae. Cellulolytic bacteria, especially Fibrobacteres, increase during HS due to a high heat resistance. Actinobacteria and Acetobacter , both acetate-producing bacteria, decreased under HS conditions. Rumen fermentation functions, blood parameters, and metabolites are also affected by the physiological responses of the animal during HS. Isoleucine, methionine, myo-inositol, lactate, tryptophan, tyrosine, 1,5-anhydro- D -sorbitol, 3-phenylpropionic acid, urea, and valine decreased under these conditions. These responses affect feed consumption and production efficiency in milk yield, growth rate, and reproduction. At the cellular level, activation of heat shock transcription factor (HSF) (located throughout the nucleus and the cytoplasm) and increased expression of heat shock proteins (HSPs) are the usual responses to cope with homeostasis. HSP70 is the most abundant HSP family responsible for the environmental stress response, while HSF1 is essential for increasing cell temperature. The expression of bovine lymphocyte antigen and histocompatibility complex class II (DRB3) is downregulated during HS, while HSP90 beta I and HSP70 1A are upregulated. HS increases the expression of the cytosolic arginine sensor for mTORC1 subunits 1 and 2, phosphorylation of mammalian target of rapamycin and decreases the phosphorylation of Janus kinase-2 (a signal transducer and activator of transcription factor-5). These changes in physiology, metabolism, and microbiomes in heat-stressed dairy cows require urgent alleviation strategies. Establishing control measures to combat HS can be facilitated by elucidating mechanisms, including proper HS assessment, access to cooling facilities, special feeding and care, efficient water systems, and supplementation with vitamins, minerals, plant extracts, and probiotics. Understanding the relationship between HS and the rumen microbiome could contribute to the development of manipulation strategies to alleviate the influence of HS. This review comprehensively elaborates on the impact of HS in dairy cows and introduces different alleviation strategies to minimize HS.
... Dairy cows are highly susceptible to heat stress owing to their large heat production but insufficient ability to dissipate heat (West, 2003). Due to global warming, the intensity and duration of heat stress are expected to increase (Hahn et al., 2009). Therefore, precise evaluation and prediction of heat stress imposed on dairy cows are largely studied given their importance for cows' production, health, and well-being and the correlated impact on energy use in the buildings. ...
... The temperature-humidity index (THI), the most widely used index model, was proposed by Thom (1959). It was initially developed for humans and then introduced into the studies related to animal thermal environments (Hahn et al., 2009). The THI incorporates dry-bulb temperature and a humidity estimator (relative humidity, web-bulb temperature, or dew point temperature), which are the measure of air sensible and latent heat content, respectively. ...
Article
Precise evaluation and prediction of heat stress on animals are largely studied, given their importance for reducing economic losses and improving animal welfare. There are serials of thermal comfort index models that attempt to quantify the severity of heat stress imposed on dairy cows. However, few index models involved the heat exchanges between cows and the environment. There is also no relevant online prediction and assessment tool for heat stress in dairy cows. The objective was of this study was to develop a new thermal comfort indicator, referred to as Skin Temperature Index for Cows (STIC), based on the heat balance equations and an integrative tool to predict and assess heat stress in dairy cows. Environmental and physiological data from a previous study was divided into the validation set (N = 902, accounting for 30%) and the evaluation set (N = 2103, 70%). We first derived the explicit expression for the theoretical model (Predicted Skin Temperature, PST) by simplifying the theoretical model and using nonlinear regression analysis. As verified by the validation set, the PST model showed an acceptable accuracy with the root mean square error of 1.165 °C, the mean absolute error of 0.918 °C, and the mean absolute percentage error of 2.62%. Then, the STIC model was obtained based on the upper and lower limits of skin temperature and the PST model. The results indicate that the determination of coefficient (R²) of STIC for rectal temperature, respiration rate, skin temperature, eye temperature were 0.48, 0.71, 0.73, and 0.42, respectively. The STIC showed significantly higher prediction with the physiological responses than other thermal comfort indices (p < 0.05) with respect to rectal temperature (r = 0.69), skin temperature (r = 0.86), and eye temperature (r = 0.65). In addition, the STIC thresholds and the adjustments of cow-related factors (body posture, average daily milk yield, and stage of lactation) to the critical threshold were established based on temperature-humidity index thresholds. Further, we developed a web-based application, the Heat Stress Indicator Tool, for thermal comfort index calculation and visualization of the level of heat stress imposed on dairy cows. Overall, the PST and STIC models incorporate air temperature, relative humidity, solar radiation, wind speed and consider the interactions of environmental parameters based on the heat exchange theory. They are powerful in assessing the heat stress of cows and have great potential for serving as precise environmental control criteria in cow buildings. Moreover, the online tool is practical for researchers and dairy farm managers.
... Heat stress and heat relief has been assessed by evaluating body temperature . Dairy animals' body temperature and RR show great sensitivity to the hot climate; thus, it is a delicate sign of heat stress (Hahn, 2009;Das et al., 2016). RR different significantly in different treatment groups in lactating Sahiwal cows. ...
... In studies conducted in facilities compost barn in Brazilian semiarid region (Silva et al., 2020;Machado et al., 2021) were reported similar findings. The authors observed the THI oscillated between values of 79 and 80, at the hottest times of the day, which is classified as danger thermal stress condition for dairy cows (Hahn et al., 2009). Thus, although the first collection phase had presented lower THI, the cows were in thermal stress during the whole experimental period. ...
Article
Full-text available
The replacement of bedding in compost dairy barns (CB) comprises a recurrent management practice, but bedding materials are often not readily available in all regions and the choice of alternative materials is necessary. The objective was to evaluate the thermal attributes of carnauba straw (CS) bedding in compost dairy barn facilities. Environmental monitoring operations were performed at a commercial farm located in Northeast Brazil. Mini weather stations were used to evaluate environmental variables. The THI was evaluated as one of the comfort parameters. Analysis of the spatial distribution of bed surface temperature (BST) in the CB was performed using geostatistical techniques. The cows remained out of the comfort zone according to THI results. The BST indicated satisfactory performance and from the thermal point of view can be used as alternative bedding material in CB facilities. However, it was observed that the CS showed fast biomass degradation compared to conventional materials, widely known. In addition, inadequate temperature values (< 45°C) were found in the deeper of the CS bed, signaling higher risks of pathogenic microbial activity. Additional studies are needed for searching the proper management plans that increase the life span of the bed formed by carnauba straw.
... [°C] and relative humidity (RH) [%] using the formula described by Hahn et al. [12]: ...
Article
Full-text available
The aim of this study was to evaluate the influence of environmental housing conditions on the milk yield of dairy cows. Measurements were taken in the summer period from June to September 2020 and in the winter period during January 2021 on a large-capacity farm of Holstein Friesian cattle. Cows were housed in free stall barn with the lying boxes and selected during the second or third lactations, in the summer period from the 51st day to the 135th day and in the winter period from the 64th day to the 120th day of lactation. The average temperature in the housing was 23 °C in summer, and 7.05 °C in winter. The average THI (thermal humidity index) value in summer was 70.43, but during the day the THI values sometimes reached 75. The dairy cows were therefore exposed to heat stress during summer. Increasing THI and temperature values negatively affected the milk yield, as there was a negative correlation between both THI and milk yield (r = -0.641; p <0.01) and temperature and milk yield (r = -0.637; p <0.01). Milk production in winter was at 58.77 kg per day and in summer at 49.55 kg per day. In the summer, the milk had a significantly lower content of fat (p <0.05), proteins (p <0.001), lactose (p <0.001), minerals (p <0.001) and conversely, a higher number of somatic cells (p <0.01). These results show that worse environmental conditions during the summer negatively affected the level of milk yield and the composition of the cows’ milk.
... Según el valor adoptado por este índice, se establecen 4 categorías: normal (THI < 74), alerta (74 = THI = 79), peligro (79 < THI = 84) y emergencia (THI > 84). La correcta interpretación de la severidad del estrés por calor incluye no solo la valoración del ITH sino también el registro de la duración y la frecuencia de la exposición (Hahn, et al., 2009). Sin embargo, este índice utiliza tan sólo dos de las muchas variables ambientales involucradas en el complejo proceso de balance térmico que los animales experimentan durante el estrés por calor . ...
Book
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Este libro presenta las memorias del XI Congreso Internacional Silvopastoril y I Congreso de la Red Global de Sistemas Silvopastoriles llevado a cabo de manera virtual entre el 3 y el 5 de Noviembre de 2021 y coordinado desde México. En el libro se consignan las ponencias entre magistrales y presentadas por los participantes. Las ponencias se agrupan en las siguientes Secciones: Sección I: Ganadería Sostenible, Sección II: Estrategias de adaptación, mitigación y resiliencia al cambio climático en los territorios, Sección III: Innovadores ganaderos en sistemas silvopastoriles y agrosilvopastoriles y Sección IV) Relevo generacional en el campo – Herederos silvopastoriles.
... In studies conducted in facilities compost barn in Brazilian semiarid region (Silva et al., 2020;Machado et al., 2021) were reported similar findings. The authors observed the THI oscillated between values of 79 and 80, at the hottest times of the day, which is classified as danger thermal stress condition for dairy cows (Hahn et al., 2009). Thus, although the first collection phase had presented lower THI, the cows were in thermal stress during the whole experimental period. ...
Article
Full-text available
The replacement of bedding in compost dairy barns (CB) comprises a recurrent management practice, but bedding materials are often not readily available in all regions and the choice of alternative materials is necessary. The objective was to evaluate the thermal attributes of carnauba straw (CS) bedding in compost dairy barn facilities. Environmental monitoring operations were performed at a commercial farm located in Northeast Brazil. Mini weather stations were used to evaluate environmental variables. The THI was evaluated as one of the comfort parameters. Analysis of the spatial distribution of bed surface temperature (BST) in the CB was performed using geostatistical techniques. The cows remained out of the comfort zone according to THI results. The BST indicated satisfactory performance and from the thermal point of view can be used as alternative bedding material in CB facilities. However, it was observed that the CS showed fast biomass degradation compared to conventional materials, widely known. In addition, inadequate temperature values (< 45°C) were found in the deeper of the CS bed, signaling higher risks of pathogenic microbial activity. Additional studies are needed for searching the proper management plans that increase the life span of the bed formed by carnauba straw.
... Según el valor adoptado por este índice, se establecen 4 categorías: normal (THI < 74), alerta (74 = THI = 79), peligro (79 < THI = 84) y emergencia (THI > 84). La correcta interpretación de la severidad del estrés por calor incluye no solo la valoración del ITH sino también el registro de la duración y la frecuencia de la exposición (Hahn, et al., 2009). Sin embargo, este índice utiliza tan sólo dos de las muchas variables ambientales involucradas en el complejo proceso de balance térmico que los animales experimentan durante el estrés por calor . ...
Conference Paper
Full-text available
Producing food through forage-based systems is the key to find the equilibrium between livestock production and ecosystem conservation. When integrated with trees and shrubs, pastures increase their productivity and resilience, improving the livelihoods of farmers and providing numerous ecosystem services, such as improved soil biodiversity, better use of water, erosion reduction, atmospheric carbon sequestration, and, perhaps, greenhouse gas mitigation. Tithonia diversifolia is a promising tropical shrub for animal feeding and grass intercropping. We hypothesized that intercropping the tropical grass Brachiaria brizantha cv. Xaraés and T. diversifolia could affect CO2, CH4 and N2O emissions from soil, reducing GHG emissions through ecosystem services. This study aimed at assessing GHG emissions from two tropical forage systems in Brazil; a single grass pasture of B. brizantha and B. brizantha intercropped with T. diversifolia. The study was carried out in an experimental area of Animal Nutrition Laboratory, Center for Nuclear Energy in Agriculture, Piracicaba, São Paulo, Brazil. The climate is humid subtropical (Köppen classification). Greenhouse gas emission flux measurements were performed in June 2021, during five days, using 16 polyvinyl chloride flux chambers randomly distributed in 8 paddocks (4 B. brizantha exclusive and 4 B. brizantha intercropped with T. diversifolia). Gas measurements were conducted for 5 minutes in each chamber and performed between 9:00 to 11:00 AM. A cavity ring-down spectrometer (Picarro® G2508 - Picarro, Inc. Santa Clara, CA) was used to measure CO2, CH4 and N2O concentrations in real-time. The analyzer cavity, the flux chamber, and the connective tubing created a closed system in which gas concentrations changed over time. Gas concentrations were measured with a flow rate of ~230 sccm at a frequency of ~1 measurement/s. The GHG fluxes were calculated taking into account the linear increase of gas concentration during the incubation period, air temperature, pressure, and chamber volume, considering the ideal gas law equation (PV = nrt). Mean soil CO2 efflux per gram of dry matter of brachiaria ranged from 35 to 45 mg CO2 m-2 h-1 in single grass and 26 to 39 mg CO2 m-2 h-1 in intercropped grass (Figure 1). During the evaluated period, the soil seemed to be a CH4 sink. Despite little differences between CH4 influx of the single grass and intercropped pasture, lower CH4 values were observed in the latter (p>0.035); this may be associated with T. diversifolia's strong and pivotal roots that can aerate the soil favoring methanotrophic bacteria. Biomass production of B. brizantha in both systems can be observed in Figure 1d, higher dry matter production was observed in intercropped pasture (p>0.036), which could be associated with the likely improvements in soil-plant interface created by the shrub.