Made available in DSpace on 2014-06-11T19:28:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-14Bitstream added on 2014-06-13T20:37:10Z : No. of bitstreams: 1 mello_jlm_me_jabo.pdf: 223780 bytes, checksum: d5e6af592ee1538903aa19f5b8746fd1 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Para avaliar os impactos de ondas de calor sobre as respostas fisiológicas e desempenho de frangos de corte submetidos ao estresse térmico foram utilizados 500 pintinhos de corte, machos e da linhagem Cobb 500, alojados com um dia de idade e criados até 45 dias em duas câmaras climatizadas equipadas com mecanismos de aquecimento e refrigeração. Metade das aves foi criada em câmara termoneutra (tratamento controle), sendo o restante alojado em outra câmara climatizada e submetido a períodos de estresse térmico (32°C por 0, 24, 48 e 72 horas), em três idades (com início aos 21, 35 e 42 dias de idade), com o objetivo de simular três ondas de calor. Os índices de desempenho foram analisados por um delineamento inteiramente casualizado (DIC) com dois tratamentos (com e sem estresse térmico) e dez repetições cada. Parâmetros fisiológicos, peso médio ao abate, rendimento de carcaça e rendimento de cortes foram analisados utilizando-se um DIC em esquema fatorial 2 x 4 (dois tratamentos e quatro períodos de estresse). O aumento da frequência respiratória das aves foi verificado a partir de 24 horas de exposição à alta temperatura para as três ondas de calor simuladas. Durante a terceira onda de calor não houve variação da temperatura retal com o aumento da duração do estresse. A temperatura do ambiente não influenciou o valor do hematócrito e as concentrações dos hormônios T3 e T4. O desempenho das aves submetidas aos tratamentos foi inferior ao do tratamento controle. O ambiente quente favoreceu a ocorrência de calos nos pés das aves. Ondas de calor influenciam negativamente o equilíbrio fisiológico de frangos de corte cujos efeitos do estresse térmico são comprovados pela queda do desempenho animal / To evaluate the impacts of heat waves in physiological responses and performance of broilers submitted to heat stress, were used 500 male animals Cobb 500, housed with one day old and bred for 45 days old in two climatic chambers equipped with heating and cooling mechanisms. 250 broilers were reared in a thermoneutral chamber (control group). The others were housed in a second chamber and submitted to heat stress periods (32°C to 0, 24, 48 e 72 hours), in three ages (started at 21, 35 and 42 days), to simulate three heat waves. The performance indexes were analyzed using a completely randomized experimental design with two treatments (with and without heat stress) done in ten repetitions. Physiological parameters, average slaughter body weight, carcass yield and commercial cuts were analyzed using a completely randomized experimental design with a 2 x 4 factorial arrangement (two treatments x four heat stress periods). The respiratory frequency increased from 24 hours of high temperature exposure for the three simulated heat waves. During the third heat wave weren’t verified changes in rectal temperature with the increased duration of stress. The environmental temperature did not influence the hematocrit value and concentrations of T3 and T4. The performance of birds subjected to the treatments was lower than the control group. The heat environment favored the occurrence of feet calluses. Heat waves negatively influenced the physiological balance of broilers, and the effects of heat stress were proven by decrease performance animal

Orientador: Hirasilva Borba / Banca: Maria Regina Barbieri de Carvalho / Banca: Marcel Manente Boiago / Resumo: Para avaliar os impactos de ondas de calor sobre as respostas fisiológicas e desempenho de frangos de corte submetidos ao estresse térmico foram utilizados 500 pintinhos de corte, machos e da linhagem Cobb 500, alojados com um dia de idade e criados até 45 dias em duas câmaras climatizadas equipadas com mecanismos de aquecimento e refrigeração. Metade das aves foi criada em câmara termoneutra (tratamento controle), sendo o restante alojado em outra câmara climatizada e submetido a períodos de estresse térmico (32°C por 0, 24, 48 e 72 horas), em três idades (com início aos 21, 35 e 42 dias de idade), com o objetivo de simular três ondas de calor. Os índices de desempenho foram analisados por um delineamento inteiramente casualizado (DIC) com dois tratamentos (com e sem estresse térmico) e dez repetições cada. Parâmetros fisiológicos, peso médio ao abate, rendimento de carcaça e rendimento de cortes foram analisados utilizando-se um DIC em esquema fatorial 2 x 4 (dois tratamentos e quatro períodos de estresse). O aumento da frequência respiratória das aves foi verificado a partir de 24 horas de exposição à alta temperatura para as três ondas de calor simuladas. Durante a terceira onda de calor não houve variação da temperatura retal com o aumento da duração do estresse. A temperatura do ambiente não influenciou o valor do hematócrito e as concentrações dos hormônios T3 e T4. O desempenho das aves submetidas aos tratamentos foi inferior ao do tratamento controle. O ambiente quente favoreceu a ocorrência de calos nos pés das aves. Ondas de calor influenciam negativamente o equilíbrio fisiológico de frangos de corte cujos efeitos do estresse térmico são comprovados pela queda do desempenho animal / Abstract: To evaluate the impacts of heat waves in physiological responses and performance of broilers submitted to heat stress, were used 500 male animals Cobb 500, housed with one day old and bred for 45 days old in two climatic chambers equipped with heating and cooling mechanisms. 250 broilers were reared in a thermoneutral chamber (control group). The others were housed in a second chamber and submitted to heat stress periods (32°C to 0, 24, 48 e 72 hours), in three ages (started at 21, 35 and 42 days), to simulate three heat waves. The performance indexes were analyzed using a completely randomized experimental design with two treatments (with and without heat stress) done in ten repetitions. Physiological parameters, average slaughter body weight, carcass yield and commercial cuts were analyzed using a completely randomized experimental design with a 2 x 4 factorial arrangement (two treatments x four heat stress periods). The respiratory frequency increased from 24 hours of high temperature exposure for the three simulated heat waves. During the third heat wave weren't verified changes in rectal temperature with the increased duration of stress. The environmental temperature did not influence the hematocrit value and concentrations of T3 and T4. The performance of birds subjected to the treatments was lower than the control group. The heat environment favored the occurrence of feet calluses. Heat waves negatively influenced the physiological balance of broilers, and the effects of heat stress were proven by decrease performance animal / Mestre

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Poucos organismos são aptos a suportar o alto estresse provocado pelas variações de temperatura e alta dessecação na faixa superior da região entremarés de costões rochosos, sendo um deles o cirripédio Chthamalus. Apesar da sua resistência, vivem constantemente próximos ao seu limite de tolerância fisiológica, o que pode influenciar suas populações. O objetivo deste estudo foi caracterizar as flutuações das populações de Chthamalus spp. na faixa superior da região entremarés em quatro costões rochosos na Baía da Ilha Grande entre 2002 e 2012, relacionando estas variações com os fatores ambientais temperatura do ar, temperatura superficial marinha e precipitação, verificando o potencial destes organismos como indicadores de variações climáticas. Para isso foram investigadas a temperatura do ar e precipitação a partir de dados da estação meteorológica de Angra dos Reis e temperatura da superfície do mar a partir de imagens de satélite (MODIS/AQUA), além das porcentagens de cobertura de Chthamalus spp. a partir de amostragens sazonais. Em geral o estudo indica que as populações foram influenciadas pelas variáveis biológicas recrutamento e competição intraespecífica. Foram verificadas grandes diferenças entre as populações nos costões rochosos estudados. A estação C1, apresentou altas coberturas de cirripédios jovens e adultos ao longo de praticamente todo o período de estudo. Na estação C2 ocorreram as maiores variações, enquanto nas estações C3 e C4 ocorreram coberturas menores e variações menos proeminentes. Estas diferenças provavelmente estiveram ligadas às características físicas de cada costão rochoso. Os anos de 2003 e 2010 foram caracterizados como de altas temperaturas (temperaturas do mar e do ar) quando comparados com os demais anos de estudo. Estes anos foram ainda caracterizados pela ocorrência do fenômeno El Niño, com altas anomalias térmicas, o que indica que este fenômeno climático influenciou as temperaturas da região. Nestes mesmos anos as coberturas de Chthamalus spp. foram relativamente baixas, o que indica que o estresse térmico afetou as populações deste cirripédio. Pode-se inferir através deste estudo que as populações de Chthamalus spp. sofrem influência direta dos fatores ambientais investigados, sendo com isso um potencial indicador de mudanças climáticas. / Few organisms are able to withstand high stress caused by temperature variations and high desiccation in the upper limit of the intertidal zone of rocky shores, as the barnacle Chthamalus. Despite their resistance, these organisms constantly live near their physiological tolerance limit, which influence their populations. The aim of this study was to characterize the fluctuations of Chthamalus spp. populations in the upper zone of four intertidal rocky shores in Ilha Grande Bay between 2002 and 2012, relating these changes to the environmental factors of air temperature, sea surface temperature and precipitation, verifying the potential of these organisms as indicators of climatic variations. For that the air temperature and precipitation were investigated using data from the meteorological station of Angra dos Reis and sea surface temperature from satellite images (MODIS/AQUA), in addition to the coverage percentages of Chthamalus spp. from seasonal samplings. In general the study indicates that populations were influenced by the biological variables recruitment and intraspecific competition. Large differences were found between the fluctuations on the rocky shores studied. The station C1, showed high coverage of barnacles and young adults throughout almost the entire period of study. At the station C2 occurred the largest variations, while in C3 and C4 stations have ocurred the smaller coverages and less prominent variations. These differences were probably related to the physical characteristics of each rocky shore. The years 2003 and 2010 were characterized as high temperature yeras (temperatures of sea and air) when compared to the other years of study. These years were also characterized by the occurrence of El Niño, with high thermal anomalies, indicating that this climatic phenomenon influenced the temperatures in the region. In these same years the coverage of Chthamalus spp. were relatively low, indicating that heat stress affected the populations of this cirripédio. Is possible infer from this study that the cirripédio Chthamalus spp. is under direct influence of environmental factors investigated, being, with that, a potential indicator of climate change.

É necessário compreendermos como os animais domésticos respondem aos fatores estressores climáticos na tentativa de amenizar a ação prejudicial das variáveis climáticas responsáveis pelo estresse térmico pelo calor. Assim, o objetivo do presente trabalho foi verificar se a termografia infravermelha poderia ser utilizada no reconhecimento dos animais sob estresse térmico pelo calor, bem como identificar qual a melhor região do animal utilizada para esse reconhecimento. Foram utilizadas 38 vacas em lactação das raças Holandês e Girolando submetidas ao estresse térmico pelo calor. A pesquisa foi conduzida na Embrapa Gado de Leite em Coronel Pacheco-MG. A coleta de dados foi feita separadamente para cada raça. Os parâmetros fisiológicos coletados foram: temperatura retal, frequência respiratória, frequência cardíaca e escore de ofegação. Para avaliação dos parâmetros ambientais utilizou-se um termômetro de globo digital modelo TGD-200. Para obtenção das imagens termográficas de diferentes regiões do corpo dos animais, utilizou-se uma câmera infravermelha (FLIR® System T300). As temperaturas ambientais variaram de 20,7°C a 37,9°C com umidade relativa chegando a 95%. Verificou-se através da termografia infravermelha a maior sensibilidade ao estresse por calor para a raça Holandês. As temperaturas obtidas pelo termógrafo mostraram-se indicadores das condições de conforto térmico. A melhor região para identificar a situação de estresse pelo calor no animal foi à região do úbere. / It is necessary to understand how domestic animals respond to climate stressors in attempt mitigate the harmful effects of climate variables responsible for heat stress. The aim of this study was to determine whether infrared thermography could be used in the recognition of animals in a state of heat stress, as well as identifying how best region of the animal used for this recognition. Was used 38 cows in lactating Holstein Friesian and Girolando breeds, under heat stress. The research was conducted at Embrapa Gado de Leite in the municipality of Coronel Pacheco in the state of Minas Gerais. Data collection was done separately for each breed. The physiological parameters collected were: rectal temperature, respiratory rate, heart rate and panting score. For assessment of environmental parameters we used a globe thermometer digital model (TGD-200). To obtain the thermograph photographs of different regions of the body of animals, we used an infrared camera (FLIR® System T300). The environmental temperature ranged from 20.7°C to 37.9°C with a relative humidity reaching 95%. It was found by infrared thermography increased sensitivity to heat stress for Holstein Friesian. The thermograph temperatures proved indicators of thermal comfort. The best region to identify heat stress in cows was udder region.

É necessário compreendermos como os animais domésticos respondem aos fatores estressores climáticos na tentativa de amenizar a ação prejudicial das variáveis climáticas responsáveis pelo estresse térmico pelo calor. Assim, o objetivo do presente trabalho foi verificar se a termografia infravermelha poderia ser utilizada no reconhecimento dos animais sob estresse térmico pelo calor, bem como identificar qual a melhor região do animal utilizada para esse reconhecimento. Foram utilizadas 38 vacas em lactação das raças Holandês e Girolando submetidas ao estresse térmico pelo calor. A pesquisa foi conduzida na Embrapa Gado de Leite em Coronel Pacheco-MG. A coleta de dados foi feita separadamente para cada raça. Os parâmetros fisiológicos coletados foram: temperatura retal, frequência respiratória, frequência cardíaca e escore de ofegação. Para avaliação dos parâmetros ambientais utilizou-se um termômetro de globo digital modelo TGD-200. Para obtenção das imagens termográficas de diferentes regiões do corpo dos animais, utilizou-se uma câmera infravermelha (FLIR® System T300). As temperaturas ambientais variaram de 20,7°C a 37,9°C com umidade relativa chegando a 95%. Verificou-se através da termografia infravermelha a maior sensibilidade ao estresse por calor para a raça Holandês. As temperaturas obtidas pelo termógrafo mostraram-se indicadores das condições de conforto térmico. A melhor região para identificar a situação de estresse pelo calor no animal foi à região do úbere. / It is necessary to understand how domestic animals respond to climate stressors in attempt mitigate the harmful effects of climate variables responsible for heat stress. The aim of this study was to determine whether infrared thermography could be used in the recognition of animals in a state of heat stress, as well as identifying how best region of the animal used for this recognition. Was used 38 cows in lactating Holstein Friesian and Girolando breeds, under heat stress. The research was conducted at Embrapa Gado de Leite in the municipality of Coronel Pacheco in the state of Minas Gerais. Data collection was done separately for each breed. The physiological parameters collected were: rectal temperature, respiratory rate, heart rate and panting score. For assessment of environmental parameters we used a globe thermometer digital model (TGD-200). To obtain the thermograph photographs of different regions of the body of animals, we used an infrared camera (FLIR® System T300). The environmental temperature ranged from 20.7°C to 37.9°C with a relative humidity reaching 95%. It was found by infrared thermography increased sensitivity to heat stress for Holstein Friesian. The thermograph temperatures proved indicators of thermal comfort. The best region to identify heat stress in cows was udder region.

Dans un contexte de réchauffement climatique et d'anthropisation, les organismes colonisant les espaces côtiers sont, et seront soumis, à des variations importantes de leur milieu de vie. Parmi ces organismes, la moule bleue Mytilus edulis constitue une espèce clé des écosystèmes intertidaux et est utilisée comme sentinelle. Au cours de cette thèse, des moules collectées sur des sites présentant des niveaux de contamination contrastés ont été conditionnées à deux niveaux de température différents avant une exposition à un stress thermique aigu. Des analyses protéomiques ont été réalisées pour explorer les effets de ces stress sur l'homéostasie des protéines. Une forte mortalité est observée exclusivement pour les individus issus du site pollué et conditionnés à des températures modérées. Chez les individus issus du site propre, une abondance de protéines de stress thermique et une sur-expression d'acteurs indiquant la mise en place d'un métabolisme anaérobie est observée. Les individus conditionnés à des températures plus élevées ont une meilleure réponse vis-à-vis des individus conditionnés aux températures modérées. Pour les moules provenant du site contaminé les réponses protéiques sont bien moins nettes et tendent à démontrer un effet additif délétère de la contamination et de la température. Là encore, les individus conditionnés aux températures les plus élevées répondent mieux. En conclusion, les individus au trait de vie non contaminés affichent de meilleures réponses physiologiques que les individus contaminés. De plus, les organismes dont l'historique thermique est favorable, i.e. conditionnés à des températures plus élevées, ont également des réponses améliorées. / Intertidal organisms live in a fluctuating environment. The blue mussel Mytilus edulis is a key species of those ecosystems and are largely use as sentinel species. Global warming associated with anthropization will expose mussels to contaminations together with increased temperatures. In addition, more frequent heatwaves are expected. In this work, mussels were collected at two sites depicting contrasted levels of contamination and thermal exposure in microcosm were conducted. Two acclimation scenarios were set up prior to exposure to an identical acute thermal stress. In order to decipher joint effects of acclimation and contamination on protein homeostasis, gill proteome comparisons were performed. High mortality was observed only for mussels collected at the contaminated site and acclimated to current temperatures. Concerning gill proteome analysis, organisms from the pristine site exhibit high abundance of thermal stress proteins. Proteoforms involved in anaerobic metabolism were also up-regulated. Interestingly, mussels acclimated to the higher temperatures show an enhanced response compare to the one acclimated to current temperatures. Concerning mussels from the contaminated site, the response appears more confusing, excepted for heat stress protein response. This may indicate deleterious effects of combined contamination and heat stress. Therefore, organisms acclimated to higher temperature display improved responses. In conclusion, mussels with a clean life history show better physiological abilities than individuals with contaminated life history. Moreover, organisms prepared to heat stress by higher acclimation temperatures also develop a more effective response.

Ocean warming causes stress to corals and records reveal that periods of thermal stress are increasing in frequency and severity. Previous studies show that thermal stress negatively impacts the reproductive output of corals. However, the transgenerational impacts of coral bleaching have never been quantified. As a consequence, it is unclear how ocean warming may alter population dynamics due to effects on reproduction and recruitment. This study quantified the transgenerational impacts of thermal stress in Montastraea cavernosa. To assess transgenerational effects of temperature stress during gametogenesis, colonies were exposed to elevated temperature for two weeks four months prior to spawning, and then returned to the reef. At spawning, eggs were collected to measure egg diameter and eggs from stressed females were significantly smaller than those from unstressed females. Then gametes from temperature stressed and unstressed corals were combined to create four fertilization crosses: unstressed female and male, unstressed female with stressed male, stressed female with unstressed male, and stressed female and male. Larvae and juveniles from each cross were kept at ambient (29°C) and elevated (31°C) temperatures. Larvae originating from stressed gametes overall had lower survival, but the separate effects of the male and female revealed paternal transgenerational acclimation and negative maternal effects. There were no transgenerational effects on initial size of juveniles, but elevated temperature in the larval stage decreased initial size. The transgenerational effects on juvenile survival were negative parental effects. Juvenile growth rate was only affected by adult male exposure to thermal stress. Juveniles originating from a thermally stressed male had higher growth rates. The timing of the thermal stress, which was during oogenesis and before spermatogenesis, most likely explains why negative effects were observed from the female and positive effects from the male. These results demonstrate that temperature stress has varying transgenerational effects.

Real world exposures to physiologically and/or psychologically stressful environments are often multifactorial. For example, high-altitude typically combines exposure to hypobaric hypoxia, solar radiation and cold ambient temperatures, while sea level thermal stress is often combined with supplementary or transient stressors such as rain, solar radiation and wind. In such complex environments, the effect of one stressor on performance may be subject to change, simply due to the presence of another independent stressor. Such differential influences can occur in three basic forms; additive, antagonistic and synergistic, each term defining a fundamental concept of inter-parameter interactions. As well as the natural occurrence of stressors in combination, understanding interactions is fundamental to experimentally modelling how multiple physiological strains integrate in their influence on or regulation of - exercise intensity. In this thesis the current literature on neuromuscular fatigue and the influence of thermal and hypoxic stress is reviewed (Chapter 1). This is followed by an outline of the methodological developments used in the subsequent experiments (Chapter 2). In the first experimental study (Chapter 3) a novel approach was adopted to investigate the combined effect of muscle cooling and hypoxia on neuromuscular fatigue in humans. The results showed that the neuromuscular system s maximal force generating capacity declined by 8.1 and 13.9% during independent cold and hypoxic stress compared to control. Force generation decreased by 21.4% during combined hypoxic-cold compared to control, closely matching the additive value of hypoxia and cold individually (22%). This was also reflected in the measurement of mechanical fatigue (electromechanical ratio), demonstrating an additive response during combined hypoxic-cold. From this study, it was concluded that when moderate hypoxia and cold environmental temperatures are combined during low intensity exercise, the level of fatigue increases additively with no interaction between these stressors. Before conducting a more complex investigation on combined stressors, a better understanding of the role of muscle temperature on central fatigue - i.e. voluntary muscle activation via the afferent signalling pathways was sought. The focus of Chapter 4 was to quantify the relationship between muscle temperature and voluntary muscle activation (central fatigue) across a wide range of temperatures. The primary finding was that different muscle temperatures can induce significant changes in voluntary activation (0.5% reduction per-degree-centigrade increase in muscle temperature) when neural drive is sustained for a prolonged effort (e.g. 120-s); however this effect is not exhibited during efforts that are brief in duration (e.g. 3-s). To further explore this finding, Chapter 5 investigated the effect of metaboreceptive feedback at two different muscle temperatures, using post-exercise muscle ischemia, on voluntary activation of a remote muscle group. The results showed that at the same perceived mental effort, peripheral limb discomfort was significantly higher with increasing muscle temperature (2% increase per-degree-centigrade increase). However any influence of increased muscle temperature on leg muscle metaboreceptive feedback did not appear to inhibit voluntary muscle activation - i.e. central control - of a remote muscle group, as represented by an equal force output and voluntary activation in the thermoneutral, contralateral leg. In Chapter 6, the psycho-sensory effects of changes in muscle temperature on central fatigue during dynamic exercise were investigated. During sustained dynamic exercise, fatigue development appeared to occur at a faster rate in hot muscle (4% increase per-degree-centigrade increase) leading to a nullification of the beneficial effects of increased muscle temperature on peak power output after a period of ~60-s maximal exercise. In support of previous studies using isometric exercise (Chapter 4 and 6), participants reported significantly higher muscular pain and discomfort in hot muscle compared to cooler muscle during dynamic exercise (2 and 1% increase per-degree-centigrade increase respectively), however this did not result in a lower power output. From Chapters 4, 5 and 6 it was concluded that in addition to faster rates of metabolite accumulation due to cardiovascular strain, it is possible that a direct sensitisation of the metaboreceptive group III and IV muscle afferents occurs in warmer muscle. This likely contributes to the reduction in voluntary muscle activation during exercise in the heat, while it may attenuate central fatigue in the cold. It was also interpreted that muscle afferents may have a similar signalling role to cutaneous sensory afferents; the latter of which are recognised for their role in providing thermal feedback to the cognitive-behavioural centres of the brain and aiding exercise regulation under thermal stress. The impact of body core and active muscle temperature on voluntary muscle activation represented a similar ratio (5 to 1 respectively) to the temperature manipulated (single leg) to non-temperature manipulated mass (rest of body) in Chapters 4, 5 and 6. This indicates that voluntary muscle activation may also be regulated based on a central meta-representation of total body heat content i.e. the summed firing rates of all activated thermoreceptors in the brain, skin, muscle, viscera and spine. Building on the initial findings of Chapter 3, Chapter 7 investigated the causative factors behind the expression of different interaction types during exposure to multi-stressor environments. This was achieved by studying the interaction between thermal stress and hypoxia on the rate of peripheral and central fatigue development during a high intensity bout of knee extension exercise to exhaustion. The results showed that during combined exposure to moderate hypoxia and mild cold, the reductions in time to exhaustion were additive of the relative effects of hypoxia and cold independently. This differs from the findings in Chapter 3, in which fatigue was additive of the absolute effects of cold and hypoxia. In contrast, combining moderate hypoxia with severe heat stress resulted in a significant antagonistic interaction on both the absolute and relative reductions in time to exhaustion i.e. the combined effect being significantly less than the sum of the individual effects. Based on the results in Chapter 7, a quantitative paradigm for understanding of systematic integration of multifactorial stressors was proposed. This is, that the interaction type between stressors is influenced by the impact magnitude of the individual stressors effect on exercise capacity, whereby the greater the stressors impact, the greater the probability that one stressor will be cancelled out by the other. This is the first study to experimentally model the overarching principles characterising the presence of simultaneous physiological strains, suggesting multifactorial integration be subject to the worst strain takes precedence when the individual strains are severe.

É necessário compreendermos como os animais domésticos respondem aos fatores estressores climáticos na tentativa de amenizar a ação prejudicial das variáveis climáticas responsáveis pelo estresse térmico pelo calor. Assim, o objetivo do presente trabalho foi verificar se a termografia infravermelha poderia ser utilizada no reconhecimento dos animais sob estresse térmico pelo calor, bem como identificar qual a melhor região do animal utilizada para esse reconhecimento. Foram utilizadas 38 vacas em lactação das raças Holandês e Girolando submetidas ao estresse térmico pelo calor. A pesquisa foi conduzida na Embrapa Gado de Leite em Coronel Pacheco-MG. A coleta de dados foi feita separadamente para cada raça. Os parâmetros fisiológicos coletados foram: temperatura retal, frequência respiratória, frequência cardíaca e escore de ofegação. Para avaliação dos parâmetros ambientais utilizou-se um termômetro de globo digital modelo TGD-200. Para obtenção das imagens termográficas de diferentes regiões do corpo dos animais, utilizou-se uma câmera infravermelha (FLIR® System T300). As temperaturas ambientais variaram de 20,7°C a 37,9°C com umidade relativa chegando a 95%. Verificou-se através da termografia infravermelha a maior sensibilidade ao estresse por calor para a raça Holandês. As temperaturas obtidas pelo termógrafo mostraram-se indicadores das condições de conforto térmico. A melhor região para identificar a situação de estresse pelo calor no animal foi à região do úbere. / It is necessary to understand how domestic animals respond to climate stressors in attempt mitigate the harmful effects of climate variables responsible for heat stress. The aim of this study was to determine whether infrared thermography could be used in the recognition of animals in a state of heat stress, as well as identifying how best region of the animal used for this recognition. Was used 38 cows in lactating Holstein Friesian and Girolando breeds, under heat stress. The research was conducted at Embrapa Gado de Leite in the municipality of Coronel Pacheco in the state of Minas Gerais. Data collection was done separately for each breed. The physiological parameters collected were: rectal temperature, respiratory rate, heart rate and panting score. For assessment of environmental parameters we used a globe thermometer digital model (TGD-200). To obtain the thermograph photographs of different regions of the body of animals, we used an infrared camera (FLIR® System T300). The environmental temperature ranged from 20.7°C to 37.9°C with a relative humidity reaching 95%. It was found by infrared thermography increased sensitivity to heat stress for Holstein Friesian. The thermograph temperatures proved indicators of thermal comfort. The best region to identify heat stress in cows was udder region.

京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第22673号 / エネ博第405号 / 新制||エネ||77(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー応用科学専攻 / (主査)教授 平藤 哲司, 教授 馬渕 守, 教授 土井 俊哉 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM