Journal of thermal biology最新文献

{"title":"Within the optimal thermal range, temperature fluctuations with similar means have little effect on offspring phenotypes: A comparison of two approaches that simulate natural nest conditions","authors":"Joshua M. Hall ,&nbsp;Sarin Tiatragul (สาริน เตียตระกูล) ,&nbsp;Mallory K. Turner ,&nbsp;Daniel A. Warner","doi":"10.1016/j.jtherbio.2024.103949","DOIUrl":"10.1016/j.jtherbio.2024.103949","url":null,"abstract":"<div><p>Temperature influences nearly every aspect of organismal function. Because aspects of global change such as urbanization and climate change influence temperature, researchers must consider how altering thermal regimes will impact biodiversity across the planet. To do so, they often measure temperature in natural and/or human-modified habitats, replicate those temperatures in laboratory experiments to understand organismal responses, and make predictions under models of future change. Consequently, accurately representing temperature in the laboratory is an important concern, yet few studies have assessed the consequences of simulating thermal conditions in different ways. We used nest temperatures for two urban-dwelling, invasive lizards (<em>Anolis sagrei</em> and <em>A. cristatellus</em>) to create two egg incubation treatments in the laboratory. Like most studies of thermal developmental plasticity, we created daily repeating thermal fluctuations; however, we used different methods to create temperature treatments that differed in the magnitude and breadth of thermal cycles, and then evaluated the effects of these different approaches on embryo development and hatchling phenotypes. Additionally, we measured embryo heart rate, a proxy for metabolism, across temperature to understand the immediate effects of treatments. We found that treatments had minimal effect on phenotypes likely because temperatures were within the optimal thermal range for each species and were similar in mean temperature. We conclude that slight differences in thermal treatments may be unimportant so long as temperatures are within a range appropriate for development, and we make several recommendations for future studies of developmental plasticity.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"125 ","pages":"Article 103949"},"PeriodicalIF":2.9,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The seasonal response of metabolic rate to projected climate change scenarios in aquatic amphipods","authors":"Milad Shokri ,&nbsp;Ludovico Lezzi ,&nbsp;Alberto Basset","doi":"10.1016/j.jtherbio.2024.103941","DOIUrl":"10.1016/j.jtherbio.2024.103941","url":null,"abstract":"<div><p>The responses of organisms to climate change are mediated primarily by its impact on their metabolic rates, which, in turn, drive various biological and ecological processes. Although there have been numerous seminal studies on the sensitivity of metabolic rate to temperature, little is empirically known about how this rate responds to seasonal temperature ranges and beyond under conservative IPCC climate change scenarios. Here, we measured the SMR of the aquatic amphipod, <em>Gammarus insensibilis</em>, which served as our subject species, with body masses ranging from 0.20 to 7.74 mg ash free weight. We assessed the response of the SMR across nine temperature levels ranging from 12 to 30.2 °C. These temperatures match seasonal temperature norms, with an incremental increase of 0.6–1.2 °C above each seasonal baseline, as projected for the years 2040 and 2100 under the modest climate change scenarios. Overall, our findings showed that the effect of temperature on SMR varies with body mass, as indicated by a negative size-temperature interaction, with larger conspecifics exhibiting less sensitivity to temperature changes than smaller ones. From the cold to warm season, the SMR increased by an average of 14% °C⁻¹, with increases of 18.4% °C⁻¹ in smaller individuals and 11.4% °C⁻¹ in larger ones. The SMR of smaller individuals peaked at a 0.6 °C increase from the current summer baseline (15.08% °C⁻¹, Q10 = 4.2), while in larger ones it peaked with a 1.2 °C increase beyond autumn temperatures (14.9% °C⁻¹, Q10 = 3.9). However, at temperatures reflecting global warming that exceed summer temperatures, the SMR of larger individuals levelled off, while that of smaller ones continued to increase. Overall, our findings suggest that smaller-sized individuals have a broader thermal window for SMR performance, while the SMR of larger-sized ones will become increasingly constrained at summer temperatures as those summer temperatures become hotter.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103941"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0306456524001591/pdfft?md5=64e70b9227c27d74f9706c4fb675841f&pid=1-s2.0-S0306456524001591-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142006582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Timing of acute cold exposure determines UCP1 and FGF21 expression - Possible interactions between the thermal environment, thermoregulatory responses, and peripheral clocks","authors":"Phong KT. Chau ,&nbsp;Elin Ryan ,&nbsp;Knut Tomas Dalen ,&nbsp;Fred Haugen","doi":"10.1016/j.jtherbio.2024.103938","DOIUrl":"10.1016/j.jtherbio.2024.103938","url":null,"abstract":"<div><p>Thermoregulation is synchronized across the circadian cycle to uphold thermal homeostasis. To test if time-of-day matters for the response to environmental cold exposure, mice were acclimated to thermoneutrality (27 °C) for 2 months were subjected acutely (8 h) to cold ambient conditions (15 °C), whereas controls were maintained at thermoneutral conditions. The thermal exposure was tested in separate groups (N = 8) at three distinct time-of-day periods: in the LIGHT phase (L); the DARK phase (D); and a mix of the two (D + L). The magnitude of UCP1 protein and mRNA induction in brown adipose tissue (BAT) in response to acute cold exposure was time-of-day sensitive, peaking in LIGHT, whereas lower induction levels were observed in D + L, and DARK. Plasma levels of FGF21 were induced 3-fold by acute cold exposure at LIGHT and D + L, compared to the time-matched thermoneutral controls, whereas cold in DARK did not cause a significant increase of FGF21 plasma levels. Cold exposure affected, in BAT, the temporal mRNA expression patterns of core circadian clock components: <em>Bmal1, Clock, Per1, Per3, Cry1, Cry2 Nr1d1,</em> and <em>Nr1d2,</em> but in the liver, none of the transcripts were modified. Behavioral assessment using the Thermal Gradient Test (TGT) showed that acute cold exposure reduced cold sensitivity in D + L, but not in DARK. RNA-seq analyses of somatosensory neurons in DRG highlighted the role of the core circadian components in these cells, as well as transcriptional changes due to acute cold exposure. This elucidates the sensory system as a gauge and potential regulator of thermoregulatory responses based on circadian physiology. In conclusion, acute cold exposure elicits time-of-day specific effects on thermoregulatory pathways, which may involve underlying changes in thermal perception. These results have implications for efforts aimed at reducing risks associated with the organization of shift work in cold environments.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103938"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0306456524001566/pdfft?md5=3b98911155c349862b6ade6e9a180d90&pid=1-s2.0-S0306456524001566-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141982598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physiologically-informed predictions of climate warming effects on native and non-native populations of blue catfish","authors":"Vaskar Nepal ,&nbsp;Maggie Dillon ,&nbsp;Mary C. Fabrizio ,&nbsp;Troy D. Tuckey","doi":"10.1016/j.jtherbio.2024.103951","DOIUrl":"10.1016/j.jtherbio.2024.103951","url":null,"abstract":"<div><p>Blue catfish <em>Ictalurus furcatus</em> has been widely introduced throughout the United States to enhance recreational fisheries. Its success in both its native and non-native range, especially in the context of climate change, will be influenced by its thermal performance. We conducted a laboratory experiment to investigate the responses of wild-captured, subadult blue catfish to temperatures ranging from 7 °C to 38 °C. Blue catfish had relatively low standard metabolic rates, indicating low energetic demands, and hence an ability to survive well even during low-food conditions. Metabolic scope and food consumption rate increased with temperature, with metabolic scope peaking at 29.1 °C, and consumption rate peaking at 32 °C. Body condition remained high up to 32 °C, but decreased drastically thereafter, suggesting limitations in maintaining metabolism through food consumption at temperatures &gt;32 °C; blue catfish cannot survive in such habitats indefinitely. Yet, many fish were able to survive temperatures as high as 38 °C for 5 days, suggesting that acute and occasionally chronic heat waves will not limit this species. Using these results, we also predicted the performance of blue catfish under prevailing conditions and under climate warming at seven locations throughout their current range in the U.S. We found that some blue catfish populations in southern and southeastern areas will likely experience temperatures above the optimal temperature for extended periods due to climate change, thus limiting potential habitat availability for this species. But, many non-native populations, especially those in northern areas such as Idaho, North Dakota, and northern California, may benefit from the expected warmer temperatures during spring and fall.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103951"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142055965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the effects of temperature, diet and threat conditions on defensive behaviour and venom regeneration in scorpion (Buthus atlantis)","authors":"Youssef El Joud ,&nbsp;Adil El Bouazzaoui ,&nbsp;Sana El-Ghali ,&nbsp;El-Mustapha Laghzaoui ,&nbsp;Oulaid Toulon ,&nbsp;Mehdi Ait Larradia ,&nbsp;Abdessamad Elmourid ,&nbsp;Youssef Ait Hamdan ,&nbsp;Mohammed Rhazi ,&nbsp;Kholoud Kahime ,&nbsp;El Hassan El Mouden ,&nbsp;Mohamed Merzouki ,&nbsp;Moulay Abdelmonaim El Hidan","doi":"10.1016/j.jtherbio.2024.103966","DOIUrl":"10.1016/j.jtherbio.2024.103966","url":null,"abstract":"<div><p>Understanding animal's behaviour and adaptation in the face of threats and predators under different biotic and abiotic conditions is fundamental in ecology. In this study we examined defensive behaviour of <em>Buthus atlantis</em> scorpion in order to assess how various factors such as temperature, prey type, and threatening conditions influence stinging behaviour, venom usage and regeneration. Our study had revealed that stings frequency was significantly lower in cooler temperature compared to the medium and warm temperature. Threatening condition had no significant effect in medium and warmer temperature, the difference between the two conditions was only significant in the cooler temperature. Conversely, we had shown that venom expenditure in <em>B. atlantis</em> is regulated by both temperature and threatening conditions. Our results show that scorpions maintained in higher temperatures yielded the greatest amount of venom compared to those in lower temperatures. Analyses of proteins concentration according to temperature and diet variation had revealed that scorpions placed in intermediate (25 °C) and warmer temperature (40 °C) had a significantly higher venom proteins concentration when compared to the cooler temperature (10 °C). Results also showed that scorpions adjust their venom usage based on their perception of danger, which can be influenced by temperature.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103966"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142173762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relation between skin temperature and muscle stiffness in masters athletes: Effect of specific training adaptation","authors":"Jakub Grzegorz Adamczyk ,&nbsp;Bartłomiej Michalak ,&nbsp;Anna Kopiczko ,&nbsp;Karol Gryko ,&nbsp;Dariusz Boguszewski ,&nbsp;Marek Popowczak ,&nbsp;Łukasz Gutkowski ,&nbsp;Robert Gajda","doi":"10.1016/j.jtherbio.2024.103952","DOIUrl":"10.1016/j.jtherbio.2024.103952","url":null,"abstract":"<div><p>Aging process is correlated with negative changes in muscles properties such as their thermal responsiveness and stiffness. At the same time masters athletes are often considered as an exemplars of successful aging. Taking this into account, the aim of the study was to establish thermal portrait of lower limbs in Masters Athletes in Track &amp; Field competing in 200 m race as well as to find out the effect of exercise on muscle stiffness. Thermal images and myotonometry were applied at restin state and immediately after the race. Indoor sprint in Masters athletes did not cause significant skin temperature changes. Only assymetries were found for Biceps femoris muscle (left vs right before p = 0,0410; after p = 0,046). Gastrocnemius was the most responsive area for sprinting in terms of muscle stiffness. Some specific adaptations to sprint were found. Masters athlete's thermal profile of lower extremities was generally characterized by symmetry. Maximal exertion did not result in an increase in muscle stiffness among the athletes, suggesting the positive influence of sports training in aging athletes.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103952"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142012425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The upper limit of thermoneutrality is not indicative of thermotolerance in bats","authors":"Shaun Welman ,&nbsp;Ana M. Breit ,&nbsp;Danielle L. Levesque ,&nbsp;Julia Nowack","doi":"10.1016/j.jtherbio.2024.103933","DOIUrl":"10.1016/j.jtherbio.2024.103933","url":null,"abstract":"<div><p>To assess the vulnerability of birds and mammals to climate change recent studies have used the upper critical limit of thermoneutrality (T_UC) as an indicator of thermal tolerance. But, the association between T_UC and thermal tolerance is not straightforward and most studies describe T_UC based solely on a deviation in metabolism from basal levels, without also considering the onset of evaporative cooling. It was argued recently that certain torpor-using bat species who survived prolonged exposure to high ambient temperatures (i.e. high thermal tolerance) experienced during extreme heat events did so by entering torpor and using facultative heterothermy to thermoconform and save on body water. Assuming that T_UC is indicative of thermal tolerance, we expect T_UC in torpor-using species to be higher than that of species which are obligate homeotherms, albeit that this distinction is based on confirmation of torpor use at low temperatures. To test this prediction, we performed a phylogenetically informed comparison of bat species known to use torpor (n = 48) and homeothermic (n = 16) bat species using published thermoregulatory datasets to compare the lower critical limit of thermoneutrality (T_LC) and T_UC in relation to body temperature. The influence of diet, biogeographical region, body mass and basal metabolic rate (BMR) was also considered. Body mass had a positive relationship with BMR, an inverse relationship with T_LC and no relationship with T_UC. Normothermic body temperature scaled positively with BMR, T_LC and T_UC. There was no relationship between diet or region and BMR, but both influenced thermal limits. Torpor-using bats had lower body mass and body temperatures than homeothermic bats, but there was no difference in BMR, T_LC and T_UC between them. Exceptional examples of physiological flexibility were observed in 34 torpor-using species and eight homeothermic species, which included 15 species of bats maintaining BMR-level metabolism at ambient temperatures as high as 40 °C (and corresponding body temperatures ∼39.2 °C). However, we argue that T_UC based on metabolism alone is not an appropriate indicator of thermal tolerance as it disregards differences in the ability of animals to tolerate higher levels of hyperthermia, importance of hydration status and capacity for evaporative cooling. Also, the variability in T_UC based on diet challenges the idea of evolutionary conservatism and warrants further consideration.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103933"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0306456524001517/pdfft?md5=89a98386621454905cec8c70cd89619e&pid=1-s2.0-S0306456524001517-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142087802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"N-acetylcysteine stimulates the proliferation and differentiation in heat-stressed skeletal muscle cells","authors":"Jiawei Lu,&nbsp;Peng Zhao,&nbsp;Xiuhu Ding,&nbsp;Huixia Li","doi":"10.1016/j.jtherbio.2024.103958","DOIUrl":"10.1016/j.jtherbio.2024.103958","url":null,"abstract":"<div><p>N-acetylcysteine (NAC) is known for its beneficial effects on health due to its antioxidant and antiapoptotic properties. This study explored the protective effects of NAC against oxidative stress in heat-stressed (HS) skeletal muscle cells and its role in promoting muscle development. NAC reduced the heat shock response by decreasing the expression of heat shock protein 70 (HSP70) in HS-induced muscle cells during proliferation and differentiation. NAC also mitigated HS-induced oxidative stress via increasing the antioxidant enzyme levels and reducing oxidant enzyme levels. Treatment with NAC at 2 mM increased cell viability from 43.68% ± 5.14%–66.69% ± 14.43% and decreased the apoptosis rate from 7.89% ± 0.53%–5.17% ± 0.11% in skeletal muscle cells. Additionally, NAC promoted the proliferation and differentiation of HS-induced skeletal muscle cells by upregulating the expression of PAX7, MYF5, MRF4 and MYHC. These findings suggest that NAC alleviates HS-induced oxidative damage in skeletal muscle cells and support muscle development.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103958"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142055964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of temperature on sexual size dimorphism during the developmental period in the broad-horned flour beetle","authors":"Kentarou Matsumura ,&nbsp;Yuto Yamamoto ,&nbsp;Kaito Yoshimura ,&nbsp;Takahisa Miyatake","doi":"10.1016/j.jtherbio.2024.103962","DOIUrl":"10.1016/j.jtherbio.2024.103962","url":null,"abstract":"<div><p>Adult size in numerous insects is strongly dependent on temperature. In several cases, a temperature–size rule is observed in which developmental temperature and adult size tradeoff. Although several previous studies have demonstrated the temperature–size rule, only a few have explored the relationship between developmental temperature and weapon traits or sexual size dimorphism. This study was conducted to investigate the size of the broad-horned flour beetle <em>Gnatocerus cornutus</em> when it was developed under different temperatures. <em>G. cornutus</em> males possess weapon traits for male–male combat and exhibit sexual size dimorphism in other morphological traits. Results showed that male weapon size and body size complied with the temperature–size rule. Furthermore, the extent of sex dimorphism in genae width, a weapon-supportive trait, were larger at lower temperatures. Our findings suggest that the temperature–size rule also influences the size of sexual traits.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103962"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermotolerance in Angus cattle is related to hair coat characteristics but not to coat color","authors":"Caroline Oliveira Farias ,&nbsp;Jessica Lazzari ,&nbsp;Ísis Soares da Cunha ,&nbsp;Paulo Bayard Dias Gonçalves ,&nbsp;Bernardo Garziera Gasperin ,&nbsp;Thomaz Lucia Jr. ,&nbsp;Eduardo Schmitt ,&nbsp;Fernando Flores Cardoso ,&nbsp;Juliana Sarubbi ,&nbsp;Rafael Gianella Mondadori","doi":"10.1016/j.jtherbio.2024.103945","DOIUrl":"10.1016/j.jtherbio.2024.103945","url":null,"abstract":"<div><p>This study evaluated the impact of coat color (CC) and hair coat characteristics (HC) on productive and physiological traits related to thermotolerance in Angus heifers. The goal was to determine if HC and/or CC were reliable indicators of thermotolerance on a large scale for future breeding programs. Ninety-three 15-month-old Angus heifers (52 black, 41 red) were evaluated in three periods on a beef cattle farm in Brazil. Heifers were classified by CC and HC, and body weight, body condition score (BCS), and reproductive tract score (RTS) were compared between groups. In the summer evaluation, surface temperature (infrared thermography), internal temperature (intravaginal sensors), sweating rate, and behavior were assessed in a subset of heifers. Temperature-humidity index (THI) was calculated using meteorological data. The proportion of heifers with short, fine, and smooth hair (HC1) increased (P &lt; 0.05) over the evaluations. Heifers with thick, long, and woolly hair (HC3) had lower (P &lt; 0.05) body weights than those with finer coats, regardless of CC. Black heifers had greater (P &lt; 0.05) puberty rates than red heifers in the first two evaluations. At a THI of 66, black heifers with HC1 exhibited a lower (P &lt; 0.05) internal temperature compared to black heifers with HC3. At a THI of 75, all heifers with HC1 had lower (P &lt; 0.05) internal temperatures, regardless of CC. Red heifers and those with HC3 experienced hyperthermia for longer (P &lt; 0.05) periods. Neither HC nor CC affected (P &gt; 0.05) surface temperatures or sweating rates. At a THI of 72, more black heifers remained standing, suggesting behavioral adaptation. In conclusion, coat color and characteristics influence thermal stress and performance in Angus heifers, though color impact is limited. Internal temperature monitoring effectively determines thermotolerance. In tropical regions, selecting for short, fine, smooth hair may improve heat tolerance.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"124 ","pages":"Article 103945"},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141982597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}