Search

Simple Summary Infrared thermography is a clinically useful method for detecting physiopathological alterations in animals through microvascular changes. It has been adapted for applications with large species, as a support tool in evaluating animal welfare, and can also contribute to productive and reproductive evaluations. This review discusses the thermal windows currently in use and characterizes their differences and limitations as resources for early detection and diagnosis in cattle and river buffaloes. Abstract Infrared thermography (IRT) is a non-ionizing, non-invasive technique that permits evaluating the comfort levels of animals, a topic of concern due to the growing interest in determining the state of health and welfare of production animals. The operating principle of IRT is detecting the heat irradiated in anatomical regions characterized by a high density of near-surface blood vessels that can regulate temperature gain or loss from/to the environment by modifying blood flow. This is essential for understanding the various vascular thermoregulation mechanisms of different species, such as rodents and ruminants’ tails. The usefulness of ocular, nasal, and vulvar thermal windows in the orbital (regio orbitalis), nasal (regio nasalis), and urogenital (regio urogenitalis) regions, respectively, has been demonstrated in cattle. However, recent evidence for the river buffalo has detected discrepancies in the data gathered from distinct thermal regions in these large ruminants, suggesting a limited sensitivity and specificity when used with this species due to various factors: the presence of hair, ambient temperature, and anatomical features, such as skin thickness and variations in blood supplies to different regions. In this review, a literature search was conducted in Scopus, Web of Science, ScienceDirect, and PubMed, using keyword combinations that included “infrared thermography”, “water buffalo”, “river buffalo” “thermoregulation”, “microvascular changes”, “lacrimal caruncle”, “udder”, “mastitis”, and “nostril”. We discuss recent findings on four thermal windows—the orbital and nasal regions, mammary gland in the udder region (regio uberis), and vulvar in the urogenital region (regio urogenitalis)—to elucidate the factors that modulate and intervene in validating thermal windows and interpreting the information they provide, as it relates to the clinical usefulness of IRT for cattle (Bos) and the river buffalo (Bubalus bubalis).

Testicular degeneration by heat is the leading cause of infertility in bulls. Beef cattle are generally farmed under hot and humid conditions, and consequently, the thermotolerance of each breed must be considered in their natural environment. This study aimed to evaluate the reproductive characteristics of Brahman bulls maintained in the grazing system, with or without shadow availability. Ten Brahman bulls aging between 24 and 30 months were allocated in two different paddocks, with or without shadow availability. The heat tolerance test was performed on three non-consecutive typical summer days. The semen samples were collected at four times points in a 14 days interval. The climate conditions were monitored throughout the experiment; and clinical evaluation, testicular consistence and scrotal circumference were measured before every semen collection. In addition, semen was evaluated regarding volume, aspect, turbulence, motility, straight movement, sperm concentration, and morphological exam. The studied Brahman bulls showed a high thermolysis capacity, high heat tolerance, and no differences in semen quality were observed between groups. A degeneração testicular causada pelo calor é a principal causa de infertilidade em touros. Bovinos de corte geralmente são criados em condições de calor e umidade, e, consequentemente, a termotolerância de cada raça deve ser considerada em seu ambiente natural. O presente trabalho teve como objetivo avaliar as características reprodutivas de touros da raça Brahman mantidos em sistema de pastejo, com ou sem disponibilidade de sombra. Dez touros Brahman com idades entre 24 e 30 meses foram alocados em dois piquetes diferentes, com ou sem disponibilidade de sombra. O teste de tolerância ao calor foi realizado em três dias típicos de verão não consecutivos. As amostras de sêmen foram coletadas em quatro momentos em intervalos de 14 dias. As condições climáticas foram monitoradas durante todo o período experimental; e a avaliação clínica, consistência testicular e a circunferência escrotal foram avaliadas antes de cada coleta de sêmen. Ainda, o sêmen foi avaliado quanto ao volume, aspecto, turbulência, motilidade, vigor, concentração espermática e exame morfológico. Os touros estudados da raça Brahman apresentaram alta capacidade de termólise, alta tolerância ao calor, e não foram observadas diferenças na qualidade do sêmen entre os grupos.

Climate change is seen as a significant threat to the sustainability of livestock production systems in many parts of the world, particularly in tropical regions. Extreme meteorological events can result in catastrophic production and death of livestock. Heat waves in particular can push vulnerable animals beyond their survival threshold limits. However, there is little information about buffalo responses to sudden changes in the thermal environment, specifically the heat waves. This study aimed to quantify the thermoregulatory and blood biochemical responses of heat-acclimatized buffaloes to a simulated heat wave. The experiment was designed in a climatic chamber with two periods of 4 days each. Twelve heat acclimated buffalo heifers aged 18 months were used. The climatic chamber environment was set as follows: 4-day period (P1) simulating the same weather conditions of a summer in humid tropical climate used as a baseline, with daily cycle with Ta and RH at 27 &plusmn, 1 &deg, C and 76% from 0600 h to 1900 h and 24 &plusmn, C and 80% from 1900 h to 0600 h, and 4-day period (P2), simulating a daily heat wave cycle, from 0600 h to 1900 h with Ta and RH kept at 36 &deg, C and 78% and from 1900 h to 0600 h, 27 &deg, C and 74%. All animals were subject to both treatments and data were analyzed by a repeated measure analysis of variance, with post-hoc pooling comparison performed by Tukey&rsquo, s test. In P2, there was observed a significant increase in respiratory frequency (p &lt, 0.01), found four times in P1. The sweating rates were quite high in both periods, still, there were significant increases in P2 compared to P1 (p &lt, 0.01) (4931 and 3201 g/m2/h, respectively). A slight but significant increase in rectal temperature was observed during the day (p &lt, 0.01), with a rising until 1900 h. The simulated heat wave in P2 did not affect the values of the erythrogram or leukogram, excluding the significant reduction in K+ (p &lt, 0.05). The low heat storage and the subsequent fast and full recovery of the thermal balance late afternoon appear to be related to the high sweating rate values. The massive sweating rate emphasizes its relevance in the maintenance of buffalo homeothermy. The absence of changes in hematological parameters has revealed the considerable physiological resilience of buffaloes toward simulated heat waves.

This study aimed to assess the thermoregulatory responses of Santa Ines (SI), Dorper x Santa Ines (CH) and White Dorper x Santa Ines sheep (CW) to direct solar radiation in Southeast Brazil. Thirty adult non-pregnant and non-lactating Santa Ines (SI) hair ewes and their crosses with Dorper (hair ewes) and White Dorper (wool ewes) were allocated into three groups n = 10 and exposed to continuous solar radiation for three consecutive days. Ocular and surface temperatures, measured by infrared thermography, the rectal temperature, respiratory rate and sweating rate were collected at 7:00, 13:00 and 20:00 h. During the experiment, the black globe temperature reached a peak at 13:00 h, reaching mean values of 43.5 °C ± 0.45 °C, representative of severe discomfort for sheep. All genotypes showed an increase in surface temperature, reaching the maximum value at 13:00 h. The wool White Dorper x Santa Ines showed significantly higher surface temperature (dorsal, ventral, and shoulder) than the other genotypes. All the genotypes showed similar rectal temperature increases, peaking at 13:00 h, with values close to 39.4 °C ± 0.12 °C. At 20:00 h, all the genotypes decreased the rectal temperature (RT), albeit not reverting to the 7:00 h values. Changes in ocular temperature values mirrored the RT. All the genotypes presented high levels of evaporative heat loss. Even though all breeds significantly increased the respiratory rate, Santa Ines exhibited significantly higher values (146 bpm) than the others (112 and 117 for CH and CW, respectively). The sweating rate was very high in all genotypes, without differences among them, and exhibiting the same trend with a maximum value at 20:00 h. This behavior reflects the continuous effort to lose heat during the day, despite the decrease in black globe temperature. This study revealed analogous thermoregulatory responses among genotypes groups studied. The three genotypes showed similar heat tolerances, albeit presenting different thermogenesis and thermolysis dynamics, as evidenced by the maintenance of rectal temperatures within physiological limits even when subjected to intense high solar radiation.

Adaptation is a relevant characteristic to be understood in livestock animals in order to maintain and raise productivity. In Brazil, the Nellore beef cattle are widely disseminated and well-adapted breed that present good thermoregulatory characteristics for tropical environment conditions. Conversely, the physiological and cellular mechanisms required for thermoregulation and thermotolerance in this breed are still limited. The aim of this study was to comprehend the heat loss efficiency at the whole animal level and heat shock response at the cellular level of Nellore cows in tropical climate conditions. Healthy purebred Nellore cows were classified according to their capacity to lose body heat as Efficient or Inefficient based on vaginal temperature which was continuously monitored by data-loggers. Rectal, tail, and ocular temperatures, sweating rate, and respiratory frequency were collected to assess other thermoregulatory responses. Peripheral mononuclear cells were used for gene expression of heat shock proteins 60, 70, and 90 induced by in vitro heat treatments at 38, 40, and 42 °C. In our findings, the Efficient cows presented higher sweating rates compared to Inefficient cows that presented higher rectal temperature with greater amplitude of vaginal temperature profile. Transcription of the HSP genes was stable at 38 and 40 °C and decreased for all HSP genes at 42 °C. In conclusion, the Nellore efficiency to lose heat was mainly associated with their sweating capacity and cellular thermotolerance confirmed by the maintenance of heat shock proteins transcripts under heat stress. Taken together, this knowledge contributes as a future key for genetic selection of adapted animals.

Made available in DSpace on 2019-10-03T18:18:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-01 The aim of this study was to compare two Portuguese (Alentejana and Mertolenga) and two exotic (Frisian and Limousine) cattle breeds in terms of the relationship between the increase in ambient temperature and the responses of the evaporative heat loss pathways and the effects on homeothermy. In the experiment, six heifers of the Alentejana, Frisian, and Mertolenga breeds and four heifers of the Limousine breed were used. The animals were placed in four temperature levels, the first one under thermoneutral conditions and the other ones with increase levels of thermal stress. When submitted to severe heat stress, the Frisian developed high thermal tachypnea (125 mov/min) and moderate sweating rates (117 g m(-2) h(-1)), which did not prevent an increase in the rectal temperature (from 38.4 degrees C to 40.0 degrees C). Moderate increases in rectal temperature were observed in the Alentejana (from 38.8 degrees C to 39.4 degrees C) and Limousine (from 38.6 degrees C to 39.4 degrees C), especially in the period of highest heat stress. The Limousine showed moderate levels of tachypnea (101 mov/min) while showing the lowest sweating rates. The Alentejana showed significant increases in sweating rate (156 g m(2) h(-1)) that played a major role in homeothermy. The Mertolenga showed a superior stability of body temperature, even in the period of highest heat stress (from 38.5 degrees C to 39.1 degrees C). Uncommonly, the maintenance of homeothermy during moderate heat stress was achieved primarily by intense tachypnea (122 mov/min). The sweating rate remained abnormally low under conditions of moderate heat stress, rising significantly (110 g m(-2) h(-1)) without evidence of stabilization, only when tendency for heat storage occurred. This unusual response of the evaporative heat loss pathways infers a different thermoregulatory strategy, suggesting a different adaptation to semi-arid environment and strong association with water metabolism. (C) 2014 Elsevier Ltd. All rights reserved. Univ Evora, ICAAM Inst Ciencias Agr & Ambientais, Evora, Portugal Univ Sao Paulo, Fac Zootecnia & Engn Alimentos, BR-05508 Sao Paulo, SP, Brazil Univ Evora, Dept Matemat, Evora, Portugal Univ Estadual Paulista, Sao Paulo, SP, Brazil Univ Evora, Dept Zootecnia, Evora, Portugal Univ Estadual Paulista, Sao Paulo, SP, Brazil

This Research Communication describes, for the first time, the detection of HSP70 in saliva of dairy cows. Thermal stress is a major environmental stress that limits animal growth, metabolism, and productivity. The cellular response to heat stress involves the synthesis of heat shock proteins (HSPs), presumably to protect the functional stability of cells at increasing temperatures. HSP70 has been found to be present in cattle blood serum and may also be present in other secretory fluids, such as saliva, as already observed in humans. The aim of this study was to detect heat shock protein HSP70 in bovine saliva. Saliva samples were taken from higher- (n = 5) and lower milk producing (n = 5) Holstein-Friesian cows in summer and in winter for the detection of HSP70. HSP70 concentrations were assayed using the ELISA technique. Salivary HSP70 concentrations ranged from 0·524 to 12·174 ng/ml in cows. Higher salivary HSP70 concentrations were significantly associated with higher milk production and higher environmental temperature, but not with rectal temperature.

This study’s main goal was to evaluate the thermoregulatory responses velocity through the variation of rectal temperature (RT), related to the thermolytic pathways, respiratory rate (RR) and sweating rate (SR) among different sheep breeds. Ninety female sheep, eighteen of each breed: Santa Ines and Morada Nova (Brazilian hair breeds), Texel, Suffolk and Ile de France (wool breeds) were challenged during three non-consecutive summer days (22°42′S, 47°18′W, and 570 m of altitude, maximum air temperature of 33.5 °C, average relative humidity of 52 ± 6.9%). The physiological variables were registered at 0800 h (T1), 1300 h (T2: after 2 h of shade rest), 1400 h (T3) (after one hour of sun exposure) and in the shade at 1415 h (T4), 1430 h (T5), 1445 h (T6) and 1500 h (T7) and a thermotolerance index (TCI) was calculated as (10-(T7 to T4)-T1). The statistical analysis was performed by a mathematical model including the fixed effects of breeds and time frames, and the interaction between these effects, besides random effects such as animal and day. The Santa Ines breed presented the lowest RT after sun exposure (39.3 ± 0.12 °C; P 0.05). Hair breeds presented RR lower (P −2 h −1 ; P > 0.05). The thermotolerance index did not differ among breeds, but it showed similar response (P > 0.05) 45 min or 1 h of shade after sun exposure. One week post shearing is not enough to wool breeds present to show thermotolerance similar to hair breeds.

Este estudo teve como objetivo a compreensão dos efeitos desencadeados pelas temperaturas elevadas na expressão gênica de proteínas de choque térmico, nomeadamente da HSPA1A e HSP90AA1, em linfócitos de fêmeas bovinas de diferentes raças e origens. Parte do projeto foi desenvolvida em Portugal, onde foram utilizadas 20 novilhas da raça Limousine e 22 da raça Mertolenga. A parte desenvolvida no Brasil decorreu com 11 novilhas da raça Holstein Frísia e 20 da raça Brahman. Os animais da raça Holstein participaram do Experimento I no qual foram coletados 4 tubos de sangue para posterior choque térmico in vitro, onde cada tudo de sangue foi submetido a diferentes temperaturas: 40 °C e 42 °C (ambos através de banhos-maria), 23 °C (mantido a temperatura ambiente) e 10 °C (na geladeira), durante duas horas. Todos os animais de todas as raças participaram no Experimento II, onde foram sujeitos ao teste de tolerância ao calor, tendo sido aferidas a temperatura retal e a frequência respiratória, e coletado sangue (após os tratamentos sombra e sol). A todas as amostras de ambos os experimentos foi realizada a lise das hemácias de modo a obter o buffy-coat. O RNA foi isolado através do método do TRIzol e a RT-PCR realizada com SuperScript III após digestão com DNAse I. A PCR em tempo real decorreu no aparelho 7500 Fast Real Time, utilizando TaqMan Gene Expression Assays para os genes alvo HSPA1A e HSP90AA1, e ACTB e PPIA como genes endógenos. Foram calculados os ΔCt (Ctalvo - Ctendógeno) assim como a expressão gênica através do método 2-ΔΔCt. A análise estatística foi realizada através de modelos lineares mistos, recorrendo ao programa R Software Project (versão 3.0.1). No Experimento I foi atestada a qualidade da relação para ambos os endógenos nas relações que estabelecem com o mRNA-HSPA1A e o mRNA-HSP90AA1, através de uma análise de regressão pairwise. Tal como era esperado os valores de expressão gênica a uma temperatura de 23 °C foram os menores, seguidos 10 °C (estresse por frio), 40 °C e 42 °C para o gene HSPA1A. No caso da HSP90AA1, foi a 40 °C que se verificou uma maior expressão gênica. No Experimento II verificou-se uma variação intra-raça algo acentuada para valores de frequência respiratória, permitindo supor que o esforço termorregulatório dos animais de uma mesma raça possa ter sido diferente. Em relação à temperatura retal a raça Brahman apresentou valores significativamente diferentes das restantes raças para a situação sol. As diferenças observadas foram provavelmente consequência dos diferentes níveis de estresse aos quais os animais estiveram sujeitos. As diferenças observadas nos ΔCt não foram muito expressivas e apenas se observaram diferenças significativas na expressão gênica relativa na raça Mertolenga entre as situações sombra e sol. Podemos concluir que o aumento planificado da temperatura de linfócitos bovinos leva a diferentes expressões gênicas relativas de HSPA1A e HSP90AA1. A expressão de mRNA-HSPA1A é tanto maior quanto maior o estresse térmico, quer por frio quer por calor. As expressões gênicas relativas de HSPA1A e HSP90AA1 exibidas por animais com diferentes capacidades termolíticas são também elas diferentes, existindo uma variabilidade individual na expressão gênica relativa de proteínas de choque térmico. The present study aimed to understand the effects triggered by high temperatures in heat shock proteins gene expression, HSPA1A and HSP90AA1, in cow lymphocytes from different breeds and origins. Part of the project was developed in Portugal, where 20 Limousin and 22 Mertolenga breed heifers were used and the second part was developed in Brazil with 11 Holstein Friesian and 20 Brahman heifers. The Holstein animals participated in Experiment I in which four blood samples were collected for subsequent in vitro heat shock, where each one of the blood samples was submitted to different temperatures: 40 ° C and 42 ° C (through water baths), 23 ° C (kept at room temperature) and 10 ° C (in refrigerator) for two hours. All animals from all breeds participated in Experiment II, where they were subjected to the heat tolerance test, where rectal temperature and respiratory rate were measured, and blood samples were collected (after shadow and after sun treatments). In all samples of both experiments was carried out the erythrocytes lysis so as to obtain the buffycoat. The RNA was isolated by the TRIzol method and RT-PCR performed with SuperScript III after digestion with DNase I. The real-time PCR apparatus took place in 7500 Real Fast Time, using TaqMan Gene Expression Assays for HSPA1A and HSP90AA1 target genes, ACTB and PPIA as endogenous genes. The ΔCt (Cttarget - Ctendogenous) were calculated as well as gene expression through the 2-ΔΔCt method. Statistical analysis was performed using linear mixed models, using the program R Project Software (version 3.0.1). In Experiment I it was attested the quality of the relationship for both endogenous with the mRNA-HSPA1A and mRNAHSP90AA1 through a pairwise regression analysis. As expected values, gene expression at a temperature of 23 °C were lower, followed by 10 °C (cold stress), 40 °C and 42 °C for the HSPA1A gene. In the case of HSP90AA1 the higher gene expression was found at 40 °C. In Experiment II, there was a slightly pronounced intra-race variation for respiratory rate values, allowing the assumption that the thermoregulatory effort of animals of the same breed may have been different. Regarding the rectal temperature, in Brahman breeds it was significantly different from the other breeds in the sun treatment. The differences observed were probably a result of different levels of stress to which the animals were subjected. The differences observed in ΔCt were not very expressive and significant differences were only observed in relative gene expression of Mertolenga breed between shade and sun treatments. We conclude that planned increasing temperature in bovine lymphocytes leads to different relative gene expression of HSPA1A and HSP90AA1. The mRNA-HSPA1A expression is greater in higher thermal stress, either by cold or by heat. The HSPA1A and HSP90AA1 relative gene expressions exhibited by animals with different thermolytic capabilities, are also different, existing an individual variability in relative gene expression of heat shock proteins.