Radiant Thermal Load Research Articles

Thermal comfort of Nelore (Bos indicus) and Canchim (Bos taurus x Bos indicus) bulls kept in an integrated crop-livestock-forestry system in a tropical climate

CONTEXTClimate change presents challenges for livestock productivity and animal health. Thus, management strategies to mitigate the effects of the global temperature increase on livestock production have become progressively relevant. However, the use of integrated crop-livestock-forestry systems to optimize the beef cattle thermal balance has not been examined more deeply. OBJECTIVEThe study aimed to evaluate the microclimate in a non-shaded pasture system (NS) and in an integrated crop-livestock-forestry system (ICLF) and its influence on thermoregulatory and endocrine responses of zebu and composite bulls, during different climatic seasons. METHODSThe experiment was carried out in a tropical region, São Carlos-SP, Brazil (21°57′42″S, 47°50′28″W). Nelore (Bos indicus) and Canchim (5/8 Bos taurus x 3/8 Bos indicus) bulls were equally allocated in a non-shaded system (NS; n = 32) or in an integrated crop-livestock-forestry system (ICLF; n = 32). The animals were monthly evaluated and the data were analyzed using a GLM Model. Means were compared using Tukey test (P < 0.05). RESULTS AND CONCLUSIONSThe ICLF system reduced the air temperature (−0.6 °C; P = 0.0010), the Black Globe Temperature and Humidity Index-BGHI (−3.8; P < 0.0001), and the Radiant Thermal Load (−104 W/m2; P < 0.0001) compared to the NS system. The infrared thermograms of NS bulls were characterized by higher temperatures on the surface of the back and in the trunk, during Autumn and Winter (P < 0.05). In addition, NS bulls presented higher respiratory rate (RR: 35.85 ± 0.88 vs 31.97 ± 0.88 breaths/min; P = 0.0210) and internal body temperature (BT: 39.54 ± 0.05 vs 39.35 ± 0.05 °C; P = 0.0057) during Autumn. There was a significant reduction in cortisol concentration (−12.13 ng/mL; P < 0.05) in both systems throughout the experiment. Nelore bulls had lower RR and BT, lower mean concentration of cortisol, and higher secretion of triiodothyronine than Canchim bulls. The ICLF system was effective in mitigating the microclimate of pastures due to the action of natural shading, providing greater thermal comfort, especially for composite animals, and favored the maintenance of homeothermy in the bulls. SIGNIFICANCEThis thesis has provided a deeper insight into the physiological mechanisms involved in the thermoregulation of cattle raised in integrated crop-livestock-forestry systems. The insights gained from this study may be of assistance to indicate ICLF as a suitable option for increasing animal welfare in tropical climates.

Placental Development and Physiological Changes in Pregnant Ewes in Silvopastoral and Open Pasture Systems during the Summer.

This study aimed to analyze the reproductive and physiological changes in ewes subjected to heat stress during pregnancy at UTFPR-Brazil. Twenty-four pregnant crossbred ewes were kept in a silvopastoral system (SP) or an open pasture system (OP) throughout the final trimester of pregnancy. Both systems were stressful, but the SP system had lower air temperature than the OP system (26.0 ± 0.38 and 26.9 ± 0.41 °C, respectively; p = 0.0288). Moreover, the radiant thermal load of the two groups presented a difference of 34 Wm-2 (p = 0.0288), and the grass temperature was also lower in the SP system compared to that in the OP system (23.4 ± 0.37 and 25.6 ± 0.44 °C, respectively; p = 0.0043). The respiratory and heart rates of animals from the OP group were higher than those from the SP group (p < 0.001), but no difference was observed in the mobilization of white blood cells (p = 0.4777), and the neutrophil count was only affected by time (p < 0.0001). As regards placental biometry, placentas in twin pregnancies had a greater membrane area (p = 0.0223), but no differences between the systems were observed in placental weight (p = 0.1522) and the number of cotyledons (p = 0.5457). We concluded that the type of rearing system used affects the thermal comfort of pregnant ewes, and that an SP system can offer more amenable microclimatic conditions, which result in greater comfort for the ewes.

The shading quality of tree species and their influence on the microclimate of the immediate surroundings in urban environments

The purpose of this paper was to assess the quality and impact of the shading offered by two types of shading trees Samanea saman (rain tree) and Searsia Pendulina (Wit Karee) of the environmental variables Dry Bulb Temperature (TBS) and Radiant Thermal Load (CTR) by selected species trees and increasing their relative air humidity (RH) on the climatic conditions of the University of Baghdad, and Baghdad Park in An Nasiriyah, Iraq. Data related to the variables described were collected by means of two sets of thermometers placed: the one in tree shade (5 m) and the second in trunk (full sun) at 10 m, from June to August 2020, for each single tree, for 3 days each hour from 10:00 am to 14:00 pm. The calculation of the percentage of the Relatively Variated Values, at 5 m and 10 m, with respect to the values obtained at 5 m for quantification of shading contribution to the attenuation and augmentation of environmental variables took place. The data were analysed by testing the following hypotheses: I TBS shade attenuation > TBS attenuation at 10 m (ii) shade CTR attenuation > CTR attenuation at 10 m and (iii) shade RH increased > RH increase at 10 m. Increased shade of TBS at 10 m. The results show the good impact on TBS and CTR mitigation and RH increases. Searsia Pendulina was the most prominent species that exhibited a general TBS attenuation range from 5% to 10%, rain tree and Karee in the UR variable with increments over 30% and Karee in the CTR shadow rates with attenuations in the order of 15%. The comparison of results in this sector with the criterion of comfort has proved the impact on improving the microclimate of the local environment of the researched arboreal species.

Microclimate and animal thermal comfort indexes in different silvopastoral system arrangements in Caatinga

The objective was to evaluate the microclimate and animal thermal comfort indexes in silvopastoral system in the Brazilian semiarid region with different woody cover levels within Caatinga trees. The experiment was carried out at the Teaching, Research and Extension Unit of the Federal Institute of Science and Technology of Ceará, Campus Limoeiro do Norte, in Chapada do Apodi, CE, in 2018. The treatments were forage grown under woody cover of 46.15% (SS46), forage grown under woody cover of 30.00% (SS30), and forage grown under woody cover of 17.64% (SS18). The evaluations were carried out during three consecutive days, in the vegetative, transition, and dormancy periods at 6 a.m.; 10 a.m.; 2 p.m. and 6 p.m.. First, the microclimate variables, relative air humidity (%), wind speed (m s-1), dry bulb temperature (°C), wet bulb temperature (°C), black globe temperature (°C), and dew point temperature (°C), were obtained for subsequent calculation of black globe temperature and humidity index and radiant thermal load (W m-2). SS46, SS30, and SS18 systems had no differences of black globe temperature and humidity index and radiant thermal load in the sun. There were significant reductions in black globe temperature and humidity index and radiant thermal load within the trees promoting improvement in the thermal environment at times of higher radiation load. The trees promoted better conditions of animal thermal comfort in all silvopastoral arrangements and periods of the year.

Postpartum behavioural response of Santa inês x dorper ewes and lambs in a silvopastoral system

In an extensive system, sheep are exposed to direct solar radiation and thermal variations throughout the day, resulting in behavioural changes and varied physiological responses. The silvopastoral system has the premise to reduce the radiant thermal load for animals under shading. However, little is known regarding the behavioural responses of ewes and lambs under shaded areas. Therefore, this study aimed to assess whether different production systems may influence the behaviour of lambs and ewes during the postpartum period. Twenty-four hair coat ewes (Dorper x Santa Inês) in the postpartum period and their lambs (n = 24) were randomly assigned to a silvopasture system or open pasture exposure, from December 2018 to February 2019. The following microclimate variables: air temperature, relative humidity, and wind speed were recorded and used to calculate the temperature and humidity index (THI). Behavioural data were obtained by 0/1 focal sampling with 10 min of observation being recorded every 30 min over 12 h. The following behavioural variables were assessed: standing at rest, lying down, standing ruminating, lying ruminating, panting and water intake. The data were analyzed using the Bayesian inference method, using the R software and the brms package. Regarding the THI values, the silvopastoral system provided a more comfortable thermal environment (75 ± 0.4) compared to an open pasture (77 ± 0.8). However, these conditions were still outside the normal range for sheep. Animals in the open pasture system were more likely to pant (probability between 0.6−0.8), while the chance of lying and standing ruminating (above 0.5) was higher in animals in the silvopastoral system. Moreover, animals in the silvopastoral group are less likely to pant (below 0.4), allowing them more time to rest and ruminate in the milder temperatures of the day. Our results highlight the potential of the silvopastoral system for the thermal comfort of sheep and lambs in the postpartum period.

MORPHO-PHYSIOLOGICAL RESPONSES OF BOS INDICUS, BOS TAURUS AND CROSSBRED WEANED HEIFERS TO SEASONAL VARIATIONS

Animals kept in extensive production systems are constantly exposed to the effects of climatic aspects, which could favour thermal discomfort, decreasing productive and reproductive performances. Utilisation of Bos taurus crosses with Bos indicus animals is increasing in the tropics aimed at improving production and it is now well known how these animals respond in such environment. The objective was to characterize the morpho-physiological thermoregulation responses of weaned heifers from four different genetic groups to infer regarding the different degrees of adaptation to heat under tropical conditions Forty-eight, pasture-kept, 6-month-old, weaned heifers from four distinct genetic groups: (1) Nellore; (2) Senepol; (3) Angus x Nellore; and, (4) ¼ Brahman x ¼ Nellore x ½ Senepol (Tri-cross) were evaluated. Skin, hair coat and rectal temperatures; sweating rate; respiratory and heart rates; visual analysis of hair and hair coat colour; hair coat temperature and thickness; and length, diameter, density and number of hairs were evaluated. In addition, the temperature-humidity index, black-globe temperature and humidity index, and radiant thermal load were determined. Angus x Nellore animals presented the lowest (P=0.008) respiratory rate. Rectal temperature did differ (P=0.001) between seasons. Angus x Nellore heifers showed the greatest (P=0.001) values for the morphological measures in the evaluated months, coinciding with thermal comfort indexes above those considered comfortable for cattle. Nellore (Bos indicus), Brahman x Nellore x Senepol, and Senepol (B. taurus) present the best adaptive traits in savanna. The utilisation of B. indicus animals or adapted breed confers desirable morphological characteristics for the tropical environment.

Improvement of thermal comfort indices in agroforestry systems in the southern Brazilian Amazon.

Agroforestry systems can minimize heat stress and improve cattle welfare, but the influence of the forest component in microclimatic changes in the southern Amazon remains unclear. This study aimed to compare the thermal comfort indices in grass monoculture and integrated systems. The three systems were pasture under full sunlight (PFS), integrated (triple-row) livestock-forestry (ILFT), and integrated (single-row) livestock-forestry (ILFs), across four seasons, for two years, from June 2017 to June 2019. We assessed photosynthetically active radiation (PAR), air temperature, relative humidity, black globe temperature, and wind speed. Thermal comfort indices such as temperature-humidity index (THI), black globe temperature-humidity index (BGHI), and radiant thermal load (RTL) were calculated based on microclimate data daily-collected from 8:00 to 16:00. The ILFT mean THI (76.8) was slightly lower than ILFS and PFS. The BGHI and RTL values decreased as shading increased (PFS>ILFs>ILFT). The most challenging heat stress conditions for grazing animals occurred predominately during winter and autumn. In conclusion, the presence of trees in pastures of the southern Amazon improved the microclimate and, consequently, the thermal comfort indices. Agroforestry systems can foster an environment with a more suitable thermal comfort or less restrictive to animal performance, which contribute to mitigating global climate change for forage-livestock systems in Brazilian Amazon.

Cooling ventilation at farrowing for sows from first to third parturition

This study aimed to evaluate the thermal comfort considering natural and cooling ventilation on the performance, physiological parameters and thermal comfort indices for sows from first to third parturition. A total of 30 sows from commercial lineage (genetic base Landrace x Large White) initially weighing 252.3±5.7, 280.8±9.5 and 324.5±4.8 kg at first, second and third parturition, respectively, were distributed in a 3x2 factorial arrangement, considering the three parturition orders and the two ventilation methods, with five replicas per treatment. The effect of ventilation methods and times of the day on relative humidity, radiant thermal load, temperature and humidity index and black globe humidity index. There was an interaction among ventilation methods and parturition order for sow weight at weaning and daily feed intake. Regarding the females physiological parameters, with the exception of rectal temperature, there was an interaction between ventilation methods and times of the day. The thermal conditioning using cooling ventilation provides better values for thermal comfort indexes of the sows and promotes an increase in feed intake, mainly in gilts.

Animal thermal comfort indexes in silvopastoral systems with different tree arrangements

This study aimed to assess solar radiation transmission and animal thermal comfort indexes in two silvopastoral systems established with different tree arrangements in a tropical region. This study was conducted between 2014 and 2017 in two silvopastoral systems, one composed by an established Urochloa (syn. Brachiaria) decumbens pasture with Brazilian native trees planted in triple rows spaced 17 m apart, and another by an established Urochloa (syn. Brachiaria) brizantha (Hochst ex A. Rich.) Stapf ‘BRS Piatã’ pasture with Eucalyptus urograndis (clone GG100) trees arranged in single rows spaced 15 m apart. In these systems and in a full-sun pasture, photosynthetically active radiation transmission, air temperature, relative humidity, black globe temperature, and wind speed were measured. These variables were used to calculate black globe temperature and humidity index (BGHI) and radiant thermal load (RTL). Higher animal thermal comfort was observed in the silvopastoral systems due to changes in the microclimate induced by the trees; notably, a decrease in solar radiation transmission. Fewer hours of potential animal thermal stress (BGHI>79) were observed in the silvopastoral systems than under the full-sun conditions, with differences up to 3 h per day. The silvopastoral systems presented lower radiant thermal load than the full-sun pasture with differences up to 22% achieved. The assessed silvopastoral systems may help livestock adapt to climate change, since they achieved the limit of BGHI considered to cause stress to animals following an increase of 2.2 °C in air temperature, compared with full-sun pastures.

SIMILITUDE AND THERMAL PERFORMANCE ON NON-CONVENTIONAL ROOFS

The objectives of this study were to evaluate the thermal comfort and the similitude between prototypes and reduced models, using non-conventional coverage with green roof and expanded clay aggregate, supported on wood frame structure. For this, were determined the Black Globe Temperature and Humidity Index (BGHI), the Human Discomfort Index (HDI), Effective Temperature (ET), Air Temperature (Tair) and Radiant Thermal Load (RTL), from March 2013 to December 2014. The results showed that there were no statistical differences to 5% significance in predicting heat indices between the prototypes and models. Observing all indexes simultaneously, it was observed that January was the month what led to the worst heat conditions, while June and July showed the worst cold conditions. It can be concluded that the use of reduced models is possible (1:2) compared to the prototype (1:1), with green roofs and expanded clay as covering element, for the prediction of thermal indexes, minimizing construction costs and use of spaces.

CONFORTO TÉRMICO EM ABRIGO INDIVIDUAL PARA BEZERROS COM FORRO NÃO CONVENCIONAL DE SUBPRODUTOS AGROINDUSTRIAIS

This study evaluated the thermal comfort conditions in two individuals calve shelter models covered with fiber cement tile without ceiling and using a ceiling made of low density particleboards from agro-industrial by-products (40% sugarcane bagasse and 60% Pinus sp. shavings) bonded with polyurethane bi-component resin based on castor oil. In the ambience study, dry bulb temperature (DBT), black globe temperature (BGT) and relative humidity (RH) of the calf hutches were evaluated. Indices, such as Black Globe Temperature and Humidity Index (BGHI) and Radiant Thermal Load (RTL), and also thermographic images of the internal surface of the shelters were studied. The use of fuzzy modeling has been proposed, allowing the comparison of the BGT, BGHI and RTL indices, and via these values, attributing the comfort situation, thus seeking to optimize the experimental evaluations. The results indicate that the presence of the ceiling did not contribute to a heat level reduction inside the shelters, which presented above the comfort conditions for the animals during the summer. Through observation, there was a reduction of the internal temperature of the surfaces of the shelter with a ceiling.

Thermal comfort indices assessed in integrated production systems in the Brazilian savannah

The objective was to evaluate the animal thermal comfort indices from two integrated croplivestock- forestry (ICLF) systems. For this, temperature? humidity index (THI), black globe temperature and humidity index (BGHI), and the radiant thermal load (RTL) were assessed. Two ICLF (ICLF-1 and ICLF-2) systems and one control system were established. On the ICLF systems, the arboreal component was the eucalyptus tree (Eucalyptus grandis 9 Eucalyptus urophylla; H13 clone), planted in simple widespaced rows. The ICLF-1 system had a tree spacing of 14 9 2 m with 357 trees per hectare, and the ICLF-2 had a tree spacing of 22 9 2 m with 227 trees per hectare. The control system had five scattered native trees per hectare, pertaining to Gochnatia and Dipteryx species. The forage component in all three systems was piata?-grass (Brachiaria brizantha cv. BRS Piata?). The experimental design was a randomized block in a sub-subplot design scheme with four replications. The presence of shade provided by the trees offered better conditions of animal comfort when compared with the condition of full sun. The ICLF-1 system, with higher tree density, provided better indicators for thermal comfort, THI, BGHI, and RTL when compared with the condition of full sun, while ICLF-2 was no different than ICLF-1 for BGHI.

English

This study aimed to analyze bioclimatic indexes: black globe temperature and humidity index (BGHI) and radiant thermal load (RTL) in Santa Ines sheep farms, with and without coverage to develop a fuzzy logical computational model to forecast variables analyzed experimentally. Ten Santa Ines sheep were placed in two cover paddocks, and one without cover. Data recorded were: air temperature schedules and black globe (°C), relative humidity (%) and wind speed (m s-1), and BGHI and RTL were calculated. Computational models were developed using fuzzy logic which had as input variables, air temperature (°C) relative humidity (%) for the output variables BGHI and RTL. Based on the experimental data, there were also certain relevance curves that conform more to the results for the model generation via Fuzzy logic. The Mandani inference method was used for the preparation of rules and defuzzification of the center of gravity method was applied. The results showed that in the critical periods, 12 to 14 h, coverage was insufficient to differentiate between stress environments. It was also found that the Fuzzy models compared with the experimental data were highly correlated with R² equal to 0.99, proving it is suitable for implementation in practice. Key words: Computational model, heat stress, shelter, simulation.

Vacas F1 Holandês x Zebu no terço final de gestação apresentam adaptação fisiológica quando criadas no ambiente semiárido

This study aimed to verify the adaptability of F1 Holstein x Zebu cows in the late pregnancy third, raised in the semiarid region of Minas Gerais, by means of physiological responses. A total of ten cows were used, all in fourth pregnancy. To characterize the climatic environment, daily collections of air temperature, air relative humidity and wind speed were carried out to enable the calculation of the Globe Temperature and Humidity Index (GTHI) and Radiant Thermal Load (RTL). The physiological parameters analyzed were: respiratory frequency, rectal temperature and surface body temperature, at 10 am and 3 pm. The adaptability tests used were Heat Tolerance Index (HTI) and Heat Tolerance Coefficient (HTC). The climatic environment was out of thermal comfort in the afternoon. There were significant differences (P <0.05) for the values of the physiological parameters. However, these responses were within the comfort range recommended for crossbred animals. The adaptability tests confirmed that the animals show adaptation to the semiarid environment of Minas Gerais, showing differences (P <0.05) on HTC between 10 am (2.52) and 3 pm (2.64), and the HTI showed an average of 9.64, a value that is very close to the index 10. It is concluded that the F1 Holstein x Zebu cows in the late pregnancy third are adapted to the climate in the semiarid region of Minas Gerais, for not altering their physiological behavior in face of the adversities of the climatic environment.

THERMAL ENVIRONMENT OF TABLE GRAPE PACKING HOUSES IN THE SÃO FRANCISCO VALLEY

The aim of this study was to characterize the thermal environment of the sorting and packing sectors of small, medium and large packing houses in the Sao Francisco Valley, Northeast of Brazil. Micrometeorological data were monitored every 15 minutes for 20 days during winter 2014 and summer 2015. The parameters evaluated were air temperature (°C), relative humidity (%) and radiant thermal load, RTL,(W/m2). External environmental data were obtained from weather stations close to the packing houses. The data obtained show that packing houses minimum and maximum temperatures were reached at 6am and 3pm, respectively, during winter and summer. Both seasons had air temperatures above 20°C, relative humidity below 90% and radiant thermal load above 450 W/m2. The construction materials that had the highest energy transmissions were the roofs. Metal roofs had the worst thermal conditioning, resulting in maximum internal air temperatures of 32.7°C and minimum relative humidity of 40.9% at 3pm, during summer. According to the results, thermal environments of sorting and packing sectors proved to be inadequate for processing table grapes, mainly during summer. These packing houses should be modified to reach the optimal thermal environment, considering the regional climatic conditions.

Shading effect on microclimate and thermal comfort indexes in integrated crop-livestock-forest systems in the Brazilian Midwest.

The objective of this paper was to perform a microclimate evaluation and determine the indexes of thermal comfort indexes, in sun and shade, in integrated crop-livestock-forest systems with different arrangements of eucalyptus and native trees, in the Brazilian Midwest. The experiment was conducted at Embrapa Beef Cattle in Campo Grande, state of Mato Grosso do Sul, Brazil, from July to September 2013. The evaluations were conducted on four consecutive days, from 8:00 a.m. to 5:00 p.m., local time (GMT -4:00), with 1 hour intervals, recording the microclimate parameters: air temperature (°C), black globe temperature (°C), wet bulb temperature (°C), relative humidity (%), and wind speed (m.s-1), for the subsequent calculation of the Temperature and Humidity Index, the Black Globe Temperature and Humidity Index, and the Radiant Thermal Load. The largest changes in microclimate parameters were found in the full sun, between 12:00 p.m. and 1:00 p.m., in less dense eucalyptus system, followed by the scattered native trees system, resulting in a maximum Temperature and Humidity Index of 81, Black Globe Temperature and Humidity Index of 88 and Radiant Thermal Load of 794Wm-2. Therefore, it is observed that with the presence of trees in pastures were possible reductions of up to 3.7% in Temperature and Humidity Index, 10.2% in the Black Globe Temperature and Humidity Index, and 28.3% of the Radiant Thermal Load in the shade. Thus, one can conclude that the presence of trees and their arrangement in the systems provide better microclimate conditions and animal thermal comfort in pastures.

Thermal efficiency of individual shelters for girolando calves in brazilian semi-arid regions

ABSTRACT The objective of this research was to evaluate the thermal efficiency of roofs used on individual shelters during milk-feeding stage of Girolando calves. The research was conducted at a farm located in a dry region of Pernambuco state, Brazil. The experimental design was completely randomized, with 27 Holstein × Gir dairy crossbred calves housed in shelters with three roofing materials (fibre cement tile, recycled tile, and thatched roofs). The recycled tiles and thatched roofs provided reductions of 18.7 and 14.6% in radiant thermal load, respectively. Regardless the roofing material, all animals increased their respiratory rate to maintain thermal equilibrium.

Thermoregulatory responses and blood parameters of locally adapted ewes under natural weather conditions of Brazilian semiarid region

&lt;p&gt;The effect of the natural weather conditions on respiratory rate, rectal temperature and hematologic parameters such as glucose, total cholesterol, triacylglycerol, total protein, albumin, globulin, red blood cells, microhematocrit, mean corpuscular volume, serum triiodothyronine (T3) and thyroxine (T4) levels was evaluated in red (RMN) and white (WMN) coat colored Morada Nova ewes, of different class of body condition score (CBCS), during the dry (from july to december) and wet (from january to june) seasons, which exhibited different (P&amp;lt;0.05) air temperature, relative humidity and radiant thermal load averages. Tukey’s test was used and the difference considered was to P&amp;lt;0.05. Significant greater averages of respiratory rate were observed in the dry period compared to the rainy period (42.26±8.96 and 36.89±8.20 breaths min-1, respectively), mainly in the RMN (45.54±8.23 breaths min-1) compared with the WMN (39.27±8.57 breaths min-1). No differences were observed in rectal temperature measurements between the dry and the wet periods (38.59±0.58 and 38.60±0.56 oC, respectively), but the WMN had higher values than the RMN (38.77±0.54 and 38.40±0.54 oC, respectively). The glucose and total cholesterol were higher in the wet season, with no variation due to breed variety and CBCS. The triacylglycerol did not change between breed varieties and seasons. The albumin was similar between varieties and in different seasons, being different in CBCS. Total protein and globulin serum were higher during the wet season, but total protein was higher and globulin was lower in better CBCS. T3 and T4 levels were higher in the rainy season (0.25±0.07 and 6.74±11.37 ?g dL-1, for T3 and T4, respectively) than in the dry season (0.18±0.08 and 6.31±1.64 ?g dL-1, for T3 and T4, respectively). The red blood cells showed no difference, but microhematocrit was higher in WMN and in the better CBCS and mean corpuscular volume was higher in the dry season. The concentration of T3 was lower in the RMN than in the WMN (0.19±0.07 and 0.24±0.08 ?g dL-1, respectively), while T4 did not differ between them (6.53±1.51 and 6.52±1.46 ?g dL-1, respectively). The Morada Nova sheep showed positive physiological responses to the heat stress, notably an increase of respiratory rate and a reduction of T3 and T4 levels. All another hematologic parameters analyzed were within the normal range for all sheep, indicating a good ability to cope with the climatic changes of the Brazilian semiarid region. Both varieties were heat tolerant, but the red variety required major adjustments to maintain homeothermy.&lt;/p&gt;

Thermoregulatory responses and blood parameters of locally adapted ewes under natural weather conditions of Brazilian semiarid region

The effect of the natural weather conditions on respiratory rate, rectal temperature and hematologic parameters such as glucose, total cholesterol, triacylglycerol, total protein, albumin, globulin, red blood cells, microhematocrit, mean corpuscular volume, serum triiodothyronine (T3) and thyroxine (T4) levels was evaluated in red (RMN) and white (WMN) coat colored Morada Nova ewes, of different class of body condition score (CBCS), during the dry (from july to december) and wet (from january to june) seasons, which exhibited different (P&lt;0.05) air temperature, relative humidity and radiant thermal load averages. Tukey’s test was used and the difference considered was to P&lt;0.05. Significant greater averages of respiratory rate were observed in the dry period compared to the rainy period (42.26±8.96 and 36.89±8.20 breaths min-1, respectively), mainly in the RMN (45.54±8.23 breaths min-1) compared with the WMN (39.27±8.57 breaths min-1). No differences were observed in rectal temperature measurements between the dry and the wet periods (38.59±0.58 and 38.60±0.56 oC, respectively), but the WMN had higher values than the RMN (38.77±0.54 and 38.40±0.54 oC, respectively). The glucose and total cholesterol were higher in the wet season, with no variation due to breed variety and CBCS. The triacylglycerol did not change between breed varieties and seasons. The albumin was similar between varieties and in different seasons, being different in CBCS. Total protein and globulin serum were higher during the wet season, but total protein was higher and globulin was lower in better CBCS. T3 and T4 levels were higher in the rainy season (0.25±0.07 and 6.74±11.37 ?g dL-1, for T3 and T4, respectively) than in the dry season (0.18±0.08 and 6.31±1.64 ?g dL-1, for T3 and T4, respectively). The red blood cells showed no difference, but microhematocrit was higher in WMN and in the better CBCS and mean corpuscular volume was higher in the dry season. The concentration of T3 was lower in the RMN than in the WMN (0.19±0.07 and 0.24±0.08 ?g dL-1, respectively), while T4 did not differ between them (6.53±1.51 and 6.52±1.46 ?g dL-1, respectively). The Morada Nova sheep showed positive physiological responses to the heat stress, notably an increase of respiratory rate and a reduction of T3 and T4 levels. All another hematologic parameters analyzed were within the normal range for all sheep, indicating a good ability to cope with the climatic changes of the Brazilian semiarid region. Both varieties were heat tolerant, but the red variety required major adjustments to maintain homeothermy.

Condicionamento térmico primário de instalações rurais por meio de diferentes tipos de cobertura

RESUMOObjetivou-se, com este trabalho, avaliar o conforto térmico proporcionado por diferentes tipos de cobertura, com base nas análises térmicas e nos índices de conforto térmico humano e zootécnico. A pesquisa foi realizada no período de 20 de março a 29 de maio de 2014, na UFRPE, no município de Recife, PE. Os tipos de cobertura analisados foram: telha de fibrocimento (Tfib), telha reciclada (Trec), telhado verde, grama, Zoysia japonica (Tgra) e telhado verde, amendoim, Arachis repens (Tame), com quatro repetições cada um; as variáveis meteorológicas foram registradas interna e externamente aos modelos. A análise térmica das coberturas foi realizada por meio de imagens termográficas e o conforto térmico das instalações foi obtido por meio dos índices de conforto, carga térmica radiante, índice de temperatura de globo negro e umidade, índice de conforto humano, índice de temperatura e umidade e temperatura efetiva. Os telhados verdes (Tame; Tgra) reduziram a temperatura da superfície interna das coberturas (5,3 e 4,4 ºC), promoveram maior atenuação da temperatura dos ambientes (1,37 e 1,35 ºC) e, consequentemente, promoveram também maior conforto térmico, em comparação com a Tfib e Trec.