Índices de estresse térmico para touros jovens Nelore criados em ambiente tropical / Thermal stress indices in young Nellore bulls raised in tropical environments

Background: Thermal stress indices are important in predicting and choosing means for mitigating heat stress and defining critical environmental conditions for animal welfare and performance. The aim of this study was to determine theassociation between 16 thermal stress indices and thermophysiological variables in young Nellore bulls raised in a tropicalpasture to determine the most effective parameter of heat stress to assist in the management of the thermal environmentand animal welfare.Materials, Methods & Results: Seventy-eight young Nellore bulls (Bos taurus indicus), with a mean age of 10.5 monthsand mean body weight of 242.09 ± 32.17 kg at first collection, and 17.92 months and body weight 335.80 ± 39.02 kg atlast collection, were used. During the experimental period, rectal temperature (RT) and surface temperature at the forehead,scapula, and groin, from which the average surface temperature (AST) was calculated, were measured. The differencebetween the AST and air temperature (i.e., AST - AT) and between the RT and AST (i.e., RT - AST) defined the thermalgradient. For the evaluation of thermal environment, the dry bulb, wet bulb, and globe temperatures, and wind speed weremeasured. Relative humidity, mean radiant temperature, solar radiation, temperature humidity index (THI), black globaltemperature humidity index (BGHI), equivalent temperature index (ETI), environmental stress index (ESI), respiratory ratepredictor (PRR), heat load index (HLI), comprehensive climate index (CCI), and index of thermal stress for cows (ITSC)were calculated. The average and maximum air temperatures were above thermal comfort levels, while the average relativehumidity was within the ideal limit for cattle. The average globe temperature was higher than the air temperature. Solarradiation presented very high values and wind speeds were very low. RT indicated normothermia in the cattle, and ASTand thermal gradient (i.e., AST - AT) indicated thermal comfort...

Índices de estresse térmico para touros jovens Nelore criados em ambiente tropical / Thermal stress indices in young Nellore bulls raised in tropical environments

Background: Thermal stress indices are important in predicting and choosing means for mitigating heat stress and defining critical environmental conditions for animal welfare and performance. The aim of this study was to determine theassociation between 16 thermal stress indices and thermophysiological variables in young Nellore bulls raised in a tropicalpasture to determine the most effective parameter of heat stress to assist in the management of the thermal environmentand animal welfare.Materials, Methods & Results: Seventy-eight young Nellore bulls (Bos taurus indicus), with a mean age of 10.5 monthsand mean body weight of 242.09 ± 32.17 kg at first collection, and 17.92 months and body weight 335.80 ± 39.02 kg atlast collection, were used. During the experimental period, rectal temperature (RT) and surface temperature at the forehead,scapula, and groin, from which the average surface temperature (AST) was calculated, were measured. The differencebetween the AST and air temperature (i.e., AST - AT) and between the RT and AST (i.e., RT - AST) defined the thermalgradient. For the evaluation of thermal environment, the dry bulb, wet bulb, and globe temperatures, and wind speed weremeasured. Relative humidity, mean radiant temperature, solar radiation, temperature humidity index (THI), black globaltemperature humidity index (BGHI), equivalent temperature index (ETI), environmental stress index (ESI), respiratory ratepredictor (PRR), heat load index (HLI), comprehensive climate index (CCI), and index of thermal stress for cows (ITSC)were calculated. The average and maximum air temperatures were above thermal comfort levels, while the average relativehumidity was within the ideal limit for cattle. The average globe temperature was higher than the air temperature. Solarradiation presented very high values and wind speeds were very low. RT indicated normothermia in the cattle, and ASTand thermal gradient (i.e., AST - AT) indicated thermal comfort...(AU)

Assessment of surface temperatures of buffalo bulls (Bubalus bubalis) raised under tropical conditions using infrared thermography / Avaliação de temperaturas superficiais de touros bubalinos (Bubalus bubalis) criados em ambiente tropical com uso da termografia infravermelha

This paper aimed to evaluate the surface temperatures of buffalo bulls using infrared thermography, considering four distinct anatomical parts over time, and to correlate surface temperatures and thermal comfort indexes. The humid tropical climate (Kõppen's Afi) was predominant in the research station where the experiment was performed and the trial lasted from April to August. Ten bulls (n=10) were evaluated every 25 days (morning: 6:00-9:00; afternoon: 12:00-15:00) and the parameters assessed were respiratory rate (RR), rectal temperature (RT), and the thermograms of surface temperature for orbital area (ORB), right flank (RF), left flank (LF) and scrotum (SCR). Climatological data was continuously monitored and the Temperature and Humidity Index (THI) and the Index of Comfort of Benezra (ICB) were calculated. The average values of THI were ≥78, and significant differences between shifts were observed (P<0.05). The ICB ranged from 1.96 to 2.25 and significant differences were observed for shifts and throughout the months (P<0.05). The averages of surface temperatures were RT=38.2±0.5°C, ORB=36.1±0.8°C, LF=33.5±2.5°C, RF=35.4±1.7ºC and SCR=33.3±1.1°C, which exhibited significant differences for shifts and throughout the months (P<0.05). Positive correlations were obtained between THI and ORB (0.72), RF (0.77), LF (0.75) and SCR (0.41) (P<0.0001). The maximum temperature of ORB showed the highest correlation with RT (0.58, P<0.0001). Therefore, the surface temperatures are subject to climatic variations and increase throughout the day, due to the variation in thermal comfort indexes, and the maximum ORB temperature was the parameter most related to rectal temperature. Lastly, the results indicate that IRT may be a useful non-invasive and accurate tool to detect the variations in ORB, LF, RF and SCR temperature in buffalo bulls.(AU)

O presente trabalho visou avaliar as temperaturas superficiais de diferentes regiões anatômicas de búfalos ao longo do tempo, por meio da termografia infravermelha, e correlacioná-las a índices bioclimatológicos de conforto térmico. O ensaio foi realizado em região de clima tropical úmido (Afi de Kõppen), de abril a agosto. Dez touros (n=10) foram avaliados a cada 25 dias (manhã: seis-nove horas; tarde: 12-15h), quanto à frequência respiratória (FR), temperatura retal (TR) e imagens termográficas da órbita ocular (ORB), flanco direito (FLd), flanco esquerdo (FLe) e escroto (ESC). Os dados climatológicos foram ininterruptamente monitorados, e calculados o índice de temperatura e umidade (ITU) e o índice de conforto de Benezra (ICB). O ITU foi ≥78, com diferença entre turnos (P<0,05). Já o ICB variou de 1,96 a 2,25 e apresentou diferenças ao longo dos meses e entre turnos (P<0,05). As temperaturas observadas foram de TR=38,2±0,5ºC, ORB=36,1±0,8ºC, FLd=33,5±2,5ºC, FLe=35,4±1,7ºC e ESC=33,3±1,1ºC, as quais variaram significativamente ao longo dos meses e entre turnos (P<0,05). O ITU apresentou correlações positivas com ORB (0,72), FLd (0,77), FLe (0,75) e ESC (0,41) (P<0,0001). A temperatura máxima de ORB apresentou a maior correlação com a TR (0,58; P<0,0001). Portanto, as temperaturas superficiais dos animais sofrem interferências das variações climáticas e se elevam ao longo do dia, devido à variação nos índices de conforto térmico; a temperatura máxima de ORB foi o parâmetro mais condicionado à temperatura retal. Também, as oscilações de temperatura de superfície de ORB, FLd, FLe e ESC podem ser aferidas em bubalinos com o uso da termografia infravermelha, de modo preciso e não invasivo.(AU)

Welfare of broilers ingesting a pre-slaughter hydric diet of lemon grass

The pre-slaughter period is considered critical in broiler production. Several factors contribute to increase the birds' stress, such as handling, harvesting, and transportation, negatively affecting their welfare. This study aimed at evaluating the addition of lemon grass (Cymbopogon citratusStapf) to the drinking water of broilers during the pre-slaughter period on their behavior, blood cortisol, and surface temperature. The study was carried out at the experimental farm of the Federal University of Grande Dourados (UFGD), Dourados, MS, Brazil. In total, 2594 broilers were distributed according to a completely randomized experimental design, in a 3x2x2 factorial arrangement, with four replicates per treatment. Treatments consisted of three different lemon grass levels (Cymbopogon citratus Stapf) used in the form of an infusion (0, 0.1, and 5 g per L of water), sex (male or female), and genetic strain (Ross(r) 308 or Cobb(r) 500). The infusion was offered when birds were 42 days old. On that day, blood was collected for blood cortisol level determination, broiler surface temperature was recorded, and an ethogram was applied to register broiler behavior. Blood cortisol level and broiler surface temperature were not affected by treatments (p>0.05). The behavior of beak opening was different between the genetic strains (p 0.05), being more frequent in Ross(r) 308 broilers. Lemon grass water content did not affect broilers' surface temperature when consumed during the pre-slaughter period.(AU)

Welfare of broilers ingesting a pre-slaughter hydric diet of lemon grass

The pre-slaughter period is considered critical in broiler production. Several factors contribute to increase the birds' stress, such as handling, harvesting, and transportation, negatively affecting their welfare. This study aimed at evaluating the addition of lemon grass (Cymbopogon citratusStapf) to the drinking water of broilers during the pre-slaughter period on their behavior, blood cortisol, and surface temperature. The study was carried out at the experimental farm of the Federal University of Grande Dourados (UFGD), Dourados, MS, Brazil. In total, 2594 broilers were distributed according to a completely randomized experimental design, in a 3x2x2 factorial arrangement, with four replicates per treatment. Treatments consisted of three different lemon grass levels (Cymbopogon citratus Stapf) used in the form of an infusion (0, 0.1, and 5 g per L of water), sex (male or female), and genetic strain (Ross(r) 308 or Cobb(r) 500). The infusion was offered when birds were 42 days old. On that day, blood was collected for blood cortisol level determination, broiler surface temperature was recorded, and an ethogram was applied to register broiler behavior. Blood cortisol level and broiler surface temperature were not affected by treatments (p>0.05). The behavior of beak opening was different between the genetic strains (p 0.05), being more frequent in Ross(r) 308 broilers. Lemon grass water content did not affect broilers' surface temperature when consumed during the pre-slaughter period.

Thermography evaluation of japanese quails (Coturnix coturnix japonica) / Avaliação termográfica de codornas japonesas (Coturnix coturnix japonica)

The present study aimed to determine variations in the body surface temperature (TS) of quails by infrared thermography. The study was conducted at the Laboratory of Biometeorology and Animal Welfare, campus Mossoró/RN, Brazil. Ten adult quails were used, males and females, in a controlled environment. The air temperature (TA) was divided into three classes (CT): CT 1 (TA < 18 °C); CT 2 (18 < TA < 22 °C); CT 3 (TA > 22 °C). The cloacal temperature (TC) was measured. The TS was measured in three regions (legs, face and feathered region). The analysis of variance for TS revealed a significant effect of the body region, CT and interaction between body region and CT. The region of the face presented TS (33.68 °C) higher than the area covered by feathers (24.73 °C) and the region of the legs (24.68 °C). The region of legs was the one that suffered the greatest variation in TS. Thus, it is concluded that Japanese quail (Coturnix coturnix japonica) have a difference in the body surface temperature according to the body region.(AU)

O presente estudo teve como objetivo determinar variaçãoes na temperatura da superfície corporal (TS) de codornas por termografia infravermelha. O estudo foi conduzido no Laboratório de Biometeorologia e Bem-Estar Animal, campus Mossoró/RN, Brasil. Foram utilizadas 10 codornas adultas, machos e fêmeas, em ambiente controlado. A temperatura do ar (TA) foi dividida em três classes (CT): CT 1 (TA < 18 °C); CT 2 (18 < TA < 22 °C); CT 3 (TA > 22 °C). A temperatura cloacal (TC) foi aferida. A TS foi aferida em três regiões (pernas, face e penas). A análise de variância para a TS revelou efeito significativo da região corporal, da CT e da interação entre região corporal e CT. A região da face apresentou TS (33,68 °C) superior à região coberta por penas (24,73 °C) e à região das patas (24,68 °C). A região das patas foi a que sofreu maior variação na TS. Dessa forma, concluise que codornas japonesas (Coturnix coturnix japonica) apresentam diferenças na temperatura superficial, conforme a região corporal.(AU)

Thermography evaluation of japanese quails (Coturnix coturnix japonica) / Avaliação termográfica de codornas japonesas (Coturnix coturnix japonica)

The present study aimed to determine variations in the body surface temperature (TS) of quails by infrared thermography. The study was conducted at the Laboratory of Biometeorology and Animal Welfare, campus Mossoró/RN, Brazil. Ten adult quails were used, males and females, in a controlled environment. The air temperature (TA) was divided into three classes (CT): CT 1 (TA 22 °C). The cloacal temperature (TC) was measured. The TS was measured in three regions (legs, face and feathered region). The analysis of variance for TS revealed a significant effect of the body region, CT and interaction between body region and CT. The region of the face presented TS (33.68 °C) higher than the area covered by feathers (24.73 °C) and the region of the legs (24.68 °C). The region of legs was the one that suffered the greatest variation in TS. Thus, it is concluded that Japanese quail (Coturnix coturnix japonica) have a difference in the body surface temperature according to the body region.

O presente estudo teve como objetivo determinar variaçãoes na temperatura da superfície corporal (TS) de codornas por termografia infravermelha. O estudo foi conduzido no Laboratório de Biometeorologia e Bem-Estar Animal, campus Mossoró/RN, Brasil. Foram utilizadas 10 codornas adultas, machos e fêmeas, em ambiente controlado. A temperatura do ar (TA) foi dividida em três classes (CT): CT 1 (TA 22 °C). A temperatura cloacal (TC) foi aferida. A TS foi aferida em três regiões (pernas, face e penas). A análise de variância para a TS revelou efeito significativo da região corporal, da CT e da interação entre região corporal e CT. A região da face apresentou TS (33,68 °C) superior à região coberta por penas (24,73 °C) e à região das patas (24,68 °C). A região das patas foi a que sofreu maior variação na TS. Dessa forma, concluise que codornas japonesas (Coturnix coturnix japonica) apresentam diferenças na temperatura superficial, conforme a região corporal.

RESPOSTAS PRODUTIVAS E FISIOLÓGICAS DE TOURINHOS HOLANDÊS x ZEBU OU NELORE SUBMETIDOS A AMBIENTE SOMBREADO OU A PLENO SOL

Objetivou-se com este estudo avaliar o índice de temperatura e umidade (ITU), a temperatura da superfície corporal, frequência respiratória, ingestão de água, consumo, digestibilidade aparente dos nutrientes, desempenho, características de carcaça e da carne de tourinhos mestiços leiteiros e Nelore, terminados em confinamento sombreado e pleno sol por 105 dias (84 dias de coleta de dados e 21 adaptação). A dieta foi silagem de capim elefante e cana-de-açúcar como volumoso, e concentrado comercial na proporção 30:70 com base na matéria seca. O delineamento experimental foi inteiramente casualizado com esquema fatorial 2 x 2, com oito repetições por tratamento, totalizando 32 animais. Foram coletadas amostras de alimentos, sobras e fezes que foram usados para determinar a ingestão de nutrientes e a digestibilidade aparente. A temperatura ambiente e umidade relativa do ar foram coletadas para o cálculo do índice de temperatura e umidade (ITU), e realizadas medições da frequência respiratória e da temperatura de superfície corporal para obtenção da resposta fisiológica. No final do experimento, os animais foram abatidos em frigorífico comercial e coletados dados de carcaça e amostras de carne. As temperaturas máximas foram (40,6 e 38,2 °C) e mínimas (15,2 e 16,2 °C) para o ambiente pleno sol e sombreado, respectivamente. O ITU máximo foi (87 vs 86) e mínimo (60 vs 64) para o ambiente pleno sol e sombreado, respectivamente. No período de estresse (13:00-16:00h), a temperatura da superfície corporal e freqüência respiratória foram maiores nos animais mestiços do sol. A ingestão de água foi maior para os animais mestiços, contudo não houve diferença para consumo de matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), extrato etéreo (EE), carboidratos não fibrosos (CNF) e nutrientes digestíveis totais (NDT). Também não houve diferença para a digestibilidade aparente da MS, PB e FDN, exceto para EE e CNF que foram maiores para os animais da raça Nelore. A média de ganho de peso diário, peso final, conversão alimentar e eficiência alimentar não foram alterados pelos tratamentos. As características de carcaça não foram influenciadas pelo ambiente, no entanto, os animais da raça Nelore apresentaram maior rendimento de carcaça quente integral, rendimento de carcaça quente e rendimento de carcaça fria, com médias de 55,22%, 53,44% e 55,92%. As temperaturas inicial e final da carcaça foram maiores para os animais mestiços assim como o pH (5,9). Os tratamentos influenciaram a força de cisalhamento que foi maior para os Nelores, a cor, o teor de proteína e matéria mineral da carne. Nessas condições de temperatura e umidade relativa do ar, o pleno sol não influencia o consumo, a digestibilidade de nutrientes, as características de carcaça, mais reduz o conforto térmico, aumenta a ingestão de água, a temperatura inicial da carcaça, a cor e a composição química da carne.

The objective of this study was to evaluate the temperature and humidity index (THI), the temperature of the body surface, respiratory rate, water intake, consumption, nutrient digestibility, performance, carcass and meat characteristics of crossbred dairy and Nellore finished in feedlot shaded and full sun for 105 days (84 days of data collection and 21 adaptation). The diet was elephant grass silage and cane sugar as forage and concentrated in the ratio 30:70 on the dry matter. The experimental design was completely randomized with factorial 2 x 2 with eight replicates per treatment, totaling 32 animals. Food samples were collected, and faeces were used to determine the nutrient intake and digestibility. The ambient temperature and relative humidity were collected to calculate the temperature and humidity index (THI), and performed measurements of respiratory rate and body surface temperature to obtain physiological response. At the end of the experiment, the animals were slaughtered at a refrigerator commercial and collected carcass data and meat samples. The maximum temperatures were (40.6 and 38.2 °C) and minimum (15.2 and 16.2 °C) to environmental sun full and shaded respectively. The maximum UTI was (87 vs 86) and minimum (60 vs 64) for environment sun full shaded, respectively. In the period of stress (13: 00-16: 00), the temperature of the body surface and respiratory rate were higher in sun crossbred. The water intake was higher for crossbred animals, but there was no difference for the intake of the dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), ether extract (EE), non-fiber carbohydrates (NFC) and total digestible nutrients (TDN). There was also no difference in the apparent digestibility of DM, CP and NDF, except for EE and NFC that were greater for Nelore cattle. The average daily weight gain, final weight, feed conversion and feed efficiency were not affected by treatments. Carcass characteristics were not influenced by the environment, however, the Nelore cattle had yield higher hot carcass integral, hot carcass yield and cold carcass yield, averaging 55.22%, 53.44% and 55 92%. The initial temperature was higher for crossbred animals as well as the pH (5.9). The treatments influenced the shear force which was higher for Nellore, color, mineral content e protein of the meat. In these conditions of temperature and relative humidity, the full sun does not influence the intake, nutrient digestibility, carcass characteristics, plus reduces the thermal comfort, increased water intake, the initial temperature of the carcass, the color and the chemical composition of meat.

Parâmetros fisiológicos de bovinos cruzados submetidos ao estresse calórico / Physiologic parameters of crossbred cattle subjected to heat stress

Caracterizaram-se as respostas fisiológicas de termorregulação em conforto e estresse calórico de bovinos cruzados F2 (½ Gir x ½ Holandês), machos e fêmeas, com idade entre 14 e 20 meses. Os animais foram alocados, em número de cinco, e submetidos ao conforto térmico (22°C a 70% de umidade relativa) por 12 horas e ao estresse calórico (42ºC e 60% de umidade relativa) durante seis horas, logo após o período de conforto, nas estações de verão e inverno, em câmara bioclimática. Nas duas etapas, foram registradas a temperatura retal (TR), a freqüência respiratória (FR) e a temperatura de superfície corporal (TSC) às 6 e 16 horas. Os animais apresentaram aumento da TR, da FR e da TSC no período de estresse calórico (P<0,05). O aumento da TR e FR foi mais acentuado no verão (P<0,05). A TSC não apresentou diferença entre as estações (P<0,05).(AU)

The thermoregulation physiological responses in thermoneutrality and heat stress of crossbred calves (½Gir x ½Holstein), males and females, with age between 14 and 20 months were studied. The animals were submitted to thermoneutrality (22°C and 70% of relative humidity) and to heat stress (42ºC and 60% of relative humidity) in summer and winter season's in bioclimatic chamber. Rectal temperature (TR), respiratory rate (FR) and body surface temperature (BST) were registered at 6 AM and 4 PM. It was observed increase in TR, FR and BST in the heat stress period (P<0.05). TR and FR increased more in the summer than in the winter (P<0.05). No difference between seasons (P>0.05) was observed for BST.(AU)