Climatic stresses and adaptation options for South Asian wheat: A systematic literature review

Information regarding the relative importance of elevated day/night-time temperatures combined with water stress on mungbean yield is limited. This study aimed to investigate the yield response of mungbean cultivars to different water stress and temperature regimes under controlled glasshouse conditions. Two mungbean cultivars, Celera II-AU and Jade-AU, were grown and evaluated under four temperature regimes with and without water stress, each replicated 10 times in a randomized complete block design. The four temperature regimes were as follows: (i) HTHT: Plants were consistently exposed to high day/high night temperatures (35/25 °C). (ii) LTHT: Plants experienced ambient day/ambient night temperatures (25/15 °C) for the first 35 days, followed by the HTHT environment. (iii) LTLT: Plants were maintained at ambient day/ambient night temperatures (25/15 °C) throughout the experiment. (iv) HTLT: Plants were subjected to high day/high night temperatures (35/25 °C) for the initial 35 days, followed by the LTLT environment. Under water stress conditions, mungbean yield declined significantly in the HTHT environment by 57% for Jade-AU and 76% for Celera II-AU compared to the LTLT environment. The highest seed yield (10.2 g plant−1 for Jade-AU and 11.4 g plant−1 for Celera II-AU) for both cultivars was observed when grown without water stress in the LTLT environment. However, yield decreased substantially when plants experienced combined heat and water stress during the reproductive stage (HTHT and LTHT environments). Without water stress, mungbean yield under the HTHT environment decreased by 30% for Jade-AU and 60% for Celera II-AU compared to the LTLT environment. Surprisingly, no significant difference in response to water stress was observed between the two cultivars. Furthermore, when grown under no-water stress and HTHT environments, the yield of Celera II-AU was reduced by 37% compared to Jade-AU. Similarly, a comparable response was seen between cultivars under no-water stress and LTHT environment. The results indicated that water and heat stress negatively affected mungbean seed yield. Moreover, it was observed that Jade-AU outperformed Celera II-AU regarding seed yield under heat-stress conditions. In conclusion, this study suggests that adjusting sowing time and selecting suitable heat-tolerant cultivars, such as Jade-AU, could enhance mungbean yield under heat and water stress conditions. The results demonstrate substantial impacts on mungbean productivity from changing climatic and water stress conditions and these findings can be utilized for improving mungbean productivity in dryland regions.

Heat and water stress induce structural and physiological changes in plants that can become decoupled within a diurnal cycle due to faster physiological responses. Understanding these physiological responses can improve the large-scale modeling of photosynthesis and evapotranspiration. Satellite solar-induced chlorophyll fluorescence observations (SIFobs) provide both structural and physiological information and are recognized as a reliable indicator for monitoring plans heat and water stresses at large scales. However, the diurnal responses of large-scale SIFobs and its physiological component, fluorescence efficiency (Φf),  to heat and water stresses remain unclear. In this study, we used data from Orbiting Carbon Observatory-3 (OCO-3) and combined a machine learning technique with the near-infrared radiance of vegetation (NIRvR) approach to model four years of hourly SIFobs and Φf data for summer seasons across mainland China. Statistical analyses of the modeled outputs were conducted to investigate the diurnal variations of SIFobs and Φf under varying water and heat stress conditions. Additionally, by comparing modeled SIFobs variations at different times of the day, we also attempted to investigate the uncertainties in assessing changes in the daily average SIFobs (ΔSIFdaily) when using daily correction factors to convert polar-orbiting satellite SIFobs into the daily averages (SIFdaily). Our results revealed that SIFobs and Φf at different times of day exhibited different variations under water and heat stress conditions, both in magnitude and sign, especially in forests. Morning and afternoon SIFobs generally exhibited larger positive or smaller negative responses than the midday period. In contrast, the morning Φf also exhibited larger positive or smaller negative responses than the midday period, but the opposite pattern was found for the afternoon Φf. Such diurnal differences in SIFobs and Φf responses became more pronounced on days with higher water and heat stresses. Additionally, morning polar-orbiting satellite SIF observations tended to overestimate ΔSIFdaily, whereas midday observations tended to underestimate it. Such biases also intensified with rising daily water and heat stress levels. Our findings broaden the understanding of the diurnal responses of SIF and especially Φf to varying heat and water stresses. The results also highlight the importance of observation time in monitoring plant water and heat stresses from polar-orbiting satellite SIF observations.

Transcriptome mapping of unfertilized pea flowers under high temperature: insights into gene regulatory networks genomics resources.

The role of methyl jasmonate and chitosan application as anti- stress materials on responses of “Anna” apple seedlings grown under water and heat stresses was evaluated during 2018 and 2019 seasons. Anna apple seedling were exposed to three levels of water regiem reated to avaialable (100, 80 and 60%), kept in the plastic greenhouse conditions at 45 ± 2°C., and treated with MeJA at 1.0 and 2.0 mM as well as chitosan at 0.5 and 1.0 %. Vegetative growth parameters, leaf mineral contents, chemical constituents and physiological attributes were detcrmined through out the development of apple seedling abiotic stress. Vegetative growth parameters including plant height (cm), average stem diameters (cm), total number of leaves/ plant, leaf area (cm2 ), number of branches/plant and shoot lengths (cm), fresh and dry weights (g/plant) greatly affected with both studied factors. Application of methyl jasmonate at 2.0 mM and chitosan at 1.0 % combined with irrigation with the three levels of recommended water regien (100, 80 and 60%), were superior than other treatments or untreated one in recording the highest values of all vegetative growth parameters in both seasons. All anti -stress materials were effective in increasing apple seedlings levels of macro (N, P and K) and micro (Fe, Zn, Mn and Cu) elements compared to untreated apple seedlings. However, chitosan treatment at 1.0 % in combination with all water regiems were more effective in improving the nutrition status of treated seedlings. Additionally, high values of total chlorophyll and carbohydrates were achieved by apple seedlings irrigated with 100% of water regiem and sprayed with higher concentration from chitosan or methyl jasmonate materials. On the other hand, the untreated seedlings under all irrigation water regiems recorded the least values in this respect. On the contrary, the treatments of 2.0 mM methyl jasmonate and 1.0 % chitosan under heat and water stress conditions were effective in reducing proline amino acid, glycine betaine and phenolic compounds contents values which is similar to the apple seedling did not expose to stresses. Generally, it could be concluded that spraying apple seedlings with methyl jasmonate at 2.0 mM and chitosan at 1.0 % in combination with all water regiem considered a good horticulture application to alleviation of a biotic stress (water and heat).

Heat stress along with low water availability at reproductive stage (terminal growth phase of wheat crop) is major contributing factor towards less wheat production in tropics and sub-tropics. Flag leaf plays a pivotal role in assimilate partitioning and stress tolerance of wheat during terminal growth phase. However, limited is known about biochemical response of flag leaf to combined and individual heat and drought stress during terminal growth phase. Therefore, current study investigated combined and individual effect of terminal drought and heat stress on water relations, photosynthetic pigments, osmolytes accumulation and antioxidants defense mechanism in flag leaf of bread wheat. Experimental treatments comprised of control, terminal drought stress alone (50% field capacity during reproductive phase), terminal heat stress alone (wheat grown inside plastic tunnel during reproductive phase) and terminal drought stress + terminal heat stress. Individual and combined imposition of drought and heat stresses significantly (p≤0.05) altered water relations, osmolyte contents, soluble proteins and sugars along with activated antioxidant defensive system in terms of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX). Turgor potential, POD and APX activities were lowest under individual heat stress; however, these were improved when drought stress was combined with heat stress. It is concluded that combined effect of drought and heat stress was more detrimental than individual stresses. The interactive effect of both stresses was hypo-additive in nature, but for some traits (like turgor potential and APX) effect of one stress neutralized the other. To best of our knowledge, this is the first report on physiological and biochemical response of flag leaf of wheat to combine heat and drought stress. These results will help future studies dealing with improved stress tolerance in wheat. However, detailed studies are needed to fully understand the genetic mechanisms behind these physiological and biochemical changes in flag leaf in response to combined heat and drought stress.

Texas tomato production is vulnerable to extreme heat in the spring-summer cropping period, which is exacerbated by the lack of superior genetic materials that can perform well in such environments. There is a dire need for selecting superior varieties that can adapt to warm environments and exhibit high yield stability under heat stress conditions. This research aimed at identifying heat-tolerant varieties under heat-stress conditions in controlled and open-field environments and was carried out in three stages. For the first experiment, 43 varieties were screened based on yield responses in natural open-field environment. From those, 18 varieties were chosen and exposed to control (greenhouse: 26/20 °C) and constant heat-stress (growth-chamber: 34/24 °C) conditions for three months. Measurements were done for chlorophyll fluorescence, chlorophyll content (SPAD), plant height, stem diameter and heat injury index (HII). The last experiment was conducted in an open field with a pool of varieties selected from the first and second experiments. Leaf gas exchange, leaf temperature, chlorophyll fluorescence, SPAD value, electrolyte leakage, heat injury index and yield were assessed. From the combined studies, we concluded that heat-tolerant genotypes selected by using chlorophyll fluorescence and HII in controlled heat-stress conditions also exhibited heat-tolerance in open-field environments. Electrolyte leakage and HII best distinguished tomato varieties in open-field environments as plants with low electrolyte leakage and HII had higher total yield. ‘Heat Master,’ ‘New Girl,’ ‘HM-1823,’ ‘Rally,’ ‘Valley Girl,’ ‘Celebrity,’ and ‘Tribeca’ were identified as high heat-tolerant varieties. Through trait correlation analysis we provide a better understanding of which traits could be useful for screening and breeding other heat-tolerant tomato varieties.

Heat stress (HS) is an environmental variable challenging pig production worldwide. It may alter carcass composition by increasing fat deposition but the mechanisms are poorly understood. Betaine is a metabolic modifier able to decrease carcass fat in pigs, but the effects of betaine on lipolysis under high temperatures are not known. Our goal was to determine a potential effect of betaine on lipolysis in the fat tissue of Iberian pigs under thermoneutral (TN) or HS conditions. Eight pigs (89 kg BW) were used to obtain explants from dorsal subcutaneous adipose tissue. Explants were cultivated under TN (37 °C) or HS conditions (41.5 °C) for 1.5 h to study direct effects of HS on acute lipolysis. Treatments included control and betaine addition (200 µM). Indirect effects of HS were examined using the culture medium amended with 1 μM isoproterenol ±10 nM insulin in the presence or absence of betaine and HS. Media glycerol was measured at the end of the incubations as a proxy of lipolysis. HS decreased basal lipolysis (-47%; p < 0.001) but increased isoproterenol-stimulated (a β-agonist) lipolysis (+31%; p < 0.01). Betaine increased non-stimulated lipolysis both under TN and HS conditions (73%; p < 0.001). As expected, isoproterenol augmented lipolysis both in TN (2714%; p < 0.001) and HS (3589%; p < 0.001) conditions. The addition of insulin to lipolysis-stimulated explants analogously diminished glycerol release in TN (-39%; p < 0.001) and HS (-50%; p < 0.001) conditions. In conclusion, HS reduced non-stimulated lipolysis in Iberian pigs in line with increased adipose tissue accretion, while betaine partly increased lipolysis, counteracting the effects of HS. Betaine supplementation could be a strategy to counteract HS-induced fattening in pigs.

Tau, a neuronal protein involved in neurodegenerative disorders such as Alzheimer disease, which is primarily described as a microtubule-associated protein, has also been observed in the nuclei of neuronal and non-neuronal cells. However, the function of the nuclear form of Tau in neurons has not yet been elucidated. In this work, we demonstrate that acute oxidative stress and mild heat stress (HS) induce the accumulation of dephosphorylated Tau in neuronal nuclei. Using chromatin immunoprecipitation assays, we demonstrate that the capacity of endogenous Tau to interact with neuronal DNA increased following HS. Comet assays performed on both wild-type and Tau-deficient neuronal cultures showed that Tau fully protected neuronal genomic DNA against HS-induced damage. Interestingly, HS-induced DNA damage observed in Tau-deficient cells was completely rescued after the overexpression of human Tau targeted to the nucleus. These results highlight a novel role for nuclear Tau as a key player in early stress response.

The field research was conducted at the Bhairahawa, Nepal in 2016/17 and 2017/18 in order to determine the physio-morphological and yield potential traits associated with heat and drought tolerance in wheat genotypes. The plant material consists of 20 genotypes out of which 17 were advanced lines and 3 were commercial varieties of Nepal. The research was carried out in alpha lattice design with two replications under three different environmental condition i.e. fully-irrigated, late sown and drought condition. In each replication there were 5 blocks consisting of 4 plots. Each plot was 4 m in length and 2.5 m in width. Each plot consists of 10 rows with a spacing of 25 cm between the rows and there was continuous sowing in a row. Seed sowing on Irrigated and Drought condition was done in 23rd November 2016 and 2017, similarly, seed sowing on Heat stress environment was done on 28th December 2016 and 2017. Data recoding were done for days to heading, days to maturity, plant height, grain yield, spikes/m2, number of grains per spike, thousand grain weights. The mean values of all yield potential traits in Heat stress and drought condition were less than in irrigated condition. Genotypes were significantly different for all phenological traits in irrigated heat stress and drought treatments. The mean number of days to heading for irrigated, drought and heat stress condition was 78.22, 76.58 and 60.8 respectively. The mean number of days to maturity for irrigated, drought and heat stress condition was 115.3, 110.41 and 99.25 respectively with the mean of 108 days. Similarly, mean plant height for irrigated, drought and heat stress condition was 89.53, 68.21 and 79.9 cm respectively with the mean of 81 cm. The mean spike/m2 for irrigated, drought and heat stress condition was 340.025, 226.11 and 262.73 respectively with the mean of 276.28. Similarly, the mean NGPS for irrigated, drought and heat stress condition was 43.32, 36.68 and 37 respectively with the mean of 39. The mean TKW for irrigated, drought and heat stress condition was 45.06,40.25 and 36.025 g respectively with the mean 40.445 g. It was observed significant difference in genotypes and environments for yield and yield potential traits. Genotype by environment interaction showed significant difference for grain yield. The mean grain yield for irrigated, drought and heat stress condition was 3.3, 1.4 and 1.79 ton/ha respectively with the mean of 2.18 ton/ha. Under normal irrigated condition, BL4708 highest mean yield with 3731.5 kg/ha and NL1328 yield lowest mean yield of 2.65 ton/ha. In heat stress condition BL4699 had maximum mean yield of 2.22 ton/ ha and NL1307 had minimum mean yield of 1.18 ton/ha. Similarly, in drought condition NL1327 had maximum mean yield of 2.0 ton/ha and NL1325 had minimum yield of 1.04 ton/ha.

The effects of Alchemilla vulgaris (AV) on haematology and serum, liver, and ovarian antioxidant status of heat-stressed quail in the late laying period were observed in this study. A 2×3 factorial design was used with 0, 1 and 3% AV fed in thermoneutral (TN) and heat stress (HS) conditions. A total of 150 quails were randomly assigned to six groups. The quails were located in temperature controlled rooms. The mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and platelet distribution width (PDW) obtained in quail fed 1% AV were higher than in 3% AV under both TN and HS conditions. Comparing 3% AV to 1% AV, the concentration of MCH obtained for 1% AV was higher in HS and lower in TN conditions. Besides, quails fed for 1% AV had a lower procalcitonin (PCT) value in HS than 3% AV but this PCT value was the same in TN. The serum malondialdehyde (MDA) was lower in 1% AV than 3% AV in both HS and TN. The ovarian MDA was lower in TN than HS. In both TN and HS conditions, the ovarian MDA value was determined higher for 1% AV than for 3% AV. The liver glutathione (GSH) value was higher in 1% AV than 3% AV in both TN and HS conditions. The Total Oxidant Capacity (TOS) value was found higher for 3% AV in TN and 1% AV in HS. The serum GSH, TOS, and oxidative stress index (OSI) values were lower for 3% AV compared to 1% AV for both TN and HS conditions, whereas for MDA value this was the opposite. The ovarium MDA and TOS values were lower for 3% AV than for 1% AV in both TN and HS. Also, the liver MDA, GSH, and Total Antioxidant Capacity (TAS) values were lower for 3% AV than for 1% AV in both TN and HS conditions. Finally, dietary AV has been shown to have a partial antioxidative effect on the defense system and also has effect on red blood cell profiles and platelet counts rather than white blood cell profiles.

Simple SummaryHeat stress (HS) causes significant milk production losses and negatively impacts animal health. Previous research indicated that heat-stressed goats eat less and degrade their skeletal muscles to cover shortages in nutrient requirements. Propylene glycol (PG) is a glucogenic precursor and may be a remedy for energy shortage in HS situations. In the current study, dairy goats were exposed to thermoneutral (TN; 15 to 20 °C) or HS (12 h/d at 37 °C and 12 h/d at 30 °C) conditions. In each ambient temperature, goats were fed a control diet (CO) or the same diet supplemented with PG. Goats supplemented with PG gained more body weight, and experienced greater blood glucose and insulin levels compared to CO goats. However, supplementation with PG depressed feed intake and milk fat content. In conclusion, feeding propylene glycol was useful to reduce body weight losses typically observed under HS conditions, but did not improve milk yield or milk composition.Heat-stressed dairy animals increase their reliance on glucose. This elevated glucose demand is partially met by increasing the conversion of glucogenic amino acids (AA) in the liver. Propylene glycol (PG) is a glucogenic precursor and was not tested in dairy goats under thermoneutral (TN) and heat stress (HS) conditions simultaneously. We hypothesize that if HS-goats are fed with PG, they would get more glucose and consequently spare more glucogenic AA for milk protein synthesis rather than gluconeogenesis. Eight multiparous dairy goats (40.8 ± 1.1 kg body weight; 84 ± 1 days in milk) were used in a replicated 4 × 4 Latin square design of 4 periods; 21 d each (14 d adaptation, 5 d for measurements, and 2 d of transition). Goats were allocated to one of 4 treatments in a 2 × 2 factorial arrangement. Factors were control (CO) without PG or 5% of PG, and thermoneutral (TN; 15 to 20 °C) or heat stress (HS; 12 h/d at 37 °C and 12 h/d at 30 °C) conditions. Feed intake, rectal temperature, respiratory rate, milk yield, milk composition, and blood metabolites were measured. Compared to TN, HS goats had lower (p < 0.01) feed intake (–34%), fat-corrected milk (–15%), and milk fat (–15%). Heat-stressed goats also tended (p < 0.10) to produce milk with lower protein (–11%) and lactose (–4%) contents. Propylene glycol increased blood glucose (+7%; p < 0.05), blood insulin (+37%; p < 0.10), and body weight gain (+68%; p < 0.05), but decreased feed intake (–9%; p < 0.10) and milk fat content (–23%; p < 0.01). Furthermore, blood non-esterified fatty acids (–49%) and β-hydroxybutyrate (–32%) decreased (p < 0.05) by PG. In conclusion, supplementation of heat-stressed dairy goats with propylene glycol caused milk fat depression syndrome, but reduced body weight loss that is typically observed under HS conditions. Supplementation with lower doses of PG would avoid the reduced feed intake and milk fat depression, but this should be tested.

<i>Background and Objective</i>: The plight of farmers are worsening by the impact of climate change. This is evident in all agro-ecological zones in Ghana. Warming and variability in rainfall pattern is causing floods and long dry spells of drought with resultant effects of reduced food crop and livestock production. Conservation Agricultural (CA) practices was therefore introduced to address the challeges of conventional tillage. CA has therefore been identified as a substitute to conventional agriculture for sustainable agricultural productivity. The objective of the study was to assess the rate of adoption of CA practices in the Bawku Municipality in the Upper East region of Ghana. <i>Methodology</i>: The study was conducted in the Bawku Municipal area of Ghana. The research design used for the study was the mixed methods. The purposive sampling technique was used to select the Bawku Municipality as the major area where agricultural conservation practices occurs in the Upper East region. The simple random sampling technique was used to select ten (10) communities in the Municipality, whilst the systematic random sampling was used to select forty (40) respondents from each community for the study. The target population for the study was maize farmers in the Bawku Municipality. In all, a total of 358 respondents were interviewed for the study. Data was taken on socio-cultural and socio-economic characteristics of respondents. Data analysis was done using the Statistical Package for Social Sciences (SPSS). Descriptive statistics, such as frequencies, percentages, and means were computed. Cross tabulations of variables were also computed and the chi-square tests used to establish relationships. <i>Results</i>: The study revealed that age, sex, level of education, religion, household size, government policy, access to credit, source of income, farm size, and access to extension services were found to have significantly influenced adoption of CA practices. The results of the study indicated that majority of farmers were aware and had knowledge about CA practices. “No-tillage with cover crops, minimum tillage with cover crops, and crop rotation with cover crops” were the main practices of conservation agriculture in the study area. The study further revealed that majority of the farmers indicated that the practices of conservation agriculture reduces soil erosion, increases soil fertility, increases soil organic matter and improves agricultural productivity. <i>Conclusion</i>: Majority of farmers adopted CA practices in full. It is recommended that the Ghanaian government should boost CA practices by instituting an annual national award scheme to award hardworking CA practioners in Ghana.

The plight of farmers are worsening by the impact of climate change. This is evident in all agro-ecological zones in Ghana. Warming and variability in rainfall pattern is causing floods and long dry spells of drought with resultant effects of reduced food crop and livestock production. Conservation Agricultural (CA) practices was therefore introduced to address the challeges of conventional tillage. CA has therefore been identified as a substitute to conventional agriculture for sustainable agricultural productivity. The objective of the study was to assess the rate of adoption of CA practices in the Bawku Municipality in the Upper East region of Ghana. The study was conducted in the Bawku Municipal area of Ghana. The research design used for the study was the mixed methods. The purposive sampling technique was used Ito select the Bawku Municipality as the major area where agricultural conservation practices occurs in the Upper East region. The simple random sampling technique was used to select ten (10) communities in the Municipality, whilst the systematic random sampling was used to select forty (40) respondents from each community for the study. The target population for the study was maize farmers in the Bawku Municipality. In all, a total of 358 respondents were interviewed for the study. Data was taken on socio-cultural and socio-economic characteristics of respondents. Data analysis was done using the Statistical Package for Social Sciences (SPSS). Descriptive statistics, such as frequencies, percentages, and means were computed. Cross tabulations of variables were also computed and the chi-square tests used to establish relationships. The study revealed that age, sex, level of education, religion, household size, government policy, access to credit, source of income, farm size, and access to extension services were found to have significantly influenced adoption of CA practices. The results of the study indicated that majority of farmers were aware and had knowledge about CA practices. “No-tillage with cover crops, minimum tillage with cover crops, and crop rotation with cover crops” were the main practices of conservation agriculture in the study area. The study further revealed that majority of the farmers indicated that the practices of conservation agriculture reduces soil erosion, increases soil fertility, increases soil organic matter and improves agricultural productivity. The survey also reveals that 81% of farmers adopted CA practices in full. It is recommended that the Ghanaian government should boost CA practices by instituting an annual nation award scheme to award hardworking CA practioners in Ghana.

Korean peninsula weather is rapidly becoming subtropical due to global warming. In summer 2018, South Korea experienced the highest temperatures since the meteorological observations recorded in 1907. Heat stress has a negative effect on Holstein cows, the most popular breed of dairy cattle in South Korea, which is susceptible to heat. To examine physiological changes in dairy cows under heat stress conditions, we analyzed the profiles circulating microRNAs isolated from whole blood samples collected under heat stress and non-heat stress conditions using small RNA sequencing. We compared the expression profiles in lactating cows under heat stress and non-heat stress conditions to understand the regulation of biological processes in heat-stressed cows. Moreover, we measured several heat stress indicators, such as rectal temperature, milk yield, and average daily gain. All these assessments showed that pregnant cows were more susceptible to heat stress than non-pregnant cows. In addition, we found the differential expression of 11 miRNAs (bta-miR-19a, bta-miR-19b, bta-miR-30a-5p, and several from the bta-miR-2284 family) in both pregnant and non-pregnant cows under heat stress conditions. In target gene prediction and gene set enrichment analysis, these miRNAs were found to be associated with the cytoskeleton, cell junction, vasculogenesis, cell proliferation, ATP synthesis, oxidative stress, and immune responses involved in heat response. These miRNAs can be used as potential biomarkers for heat stress.

Korean peninsula weather is rapidly becoming subtropical due to global warming. In summer 2018, South Korea experienced the highest temperatures since the meteorological observations recorded in 1907. Heat stress has a negative effect on Holstein cows, the most popular breed of dairy cattle in South Korea, which is susceptible to heat. To examine physiological changes in dairy cows under heat stress conditions, we analyzed the profiles circulating microRNAs isolated from whole blood samples collected under heat stress and non-heat stress conditions using small RNA sequencing. We compared the expression profiles in lactating cows under heat stress and non-heat stress conditions to understand the regulation of biological processes in heat-stressed cows. Moreover, we measured several heat stress indicators, such as rectal temperature, milk yield, and average daily gain. All these assessments showed that pregnant cows were more susceptible to heat stress than non-pregnant cows. In addition, we found the differential expression of 11 miRNAs (bta-miR-19a, bta-miR-19b, bta-miR-30a-5p, and several from the bta-miR-2284 family) in both pregnant and non-pregnant cows under heat stress conditions. In target gene prediction and gene set enrichment analysis, these miRNAs were found to be associated with the cytoskeleton, cell junction, vasculogenesis, cell proliferation, ATP synthesis, oxidative stress, and immune responses involved in heat response. These miRNAs can be used as potential biomarkers for heat stress.