Animal Thermal Comfort Research Articles

A CFD Methodology for the Modelling of Animal Thermal Welfare in Hybrid Ventilated Livestock Buildings

Computational fluid dynamics (CFD) may aid the design of barn ventilation systems by simulating indoor cattle thermal welfare. In the literature, CFD models of mechanically and naturally ventilated barns are proposed separately. Hybrid ventilation relies on cross effects between air change mechanisms that cannot be studied using existing models. The objective of this study was to develop a CFD methodology for modelling animal thermal comfort in hybrid ventilated barns. To check the capability of CFD as a design evaluation tool, a real case study (with exhaust blowers) and an alternative roof layout (with ridge gaps) were simulated in summer and winter weather. Typical phenomena of natural and mechanical ventilation were considered: buoyancy, solar radiation, and wind together with high-speed fans and exhaust blowers. Cattle thermal load was determined from a daily animal energy balance, and the assessment of thermal welfare was performed using thermohygrometric indexes. Results highlight that the current ventilation layout ensures adequate thermal welfare on average, despite large nonuniformity between stalls. The predicted intensity of heat stress was successfully compared with experimental measurements of heavy breathing duration. Results show strong interactions between natural and mechanical ventilation, underlining the need for an integrated simulation methodology.

Use of Solar Panels for Shade for Holstein Heifers.

Animal Agrivoltaics combines electric energy generation, animal thermal comfort, and sustainable production at the same time. This model of production can foster the sustainable intensification of dairy production in tropical areas where solar irradiance is high and nearly constant throughout the year. In this study, we propose Animal Agrivoltaics as an alternative practice to reduce the heat load and eCH4 emissions from dairy heifers in tropical areas. To attest this hypothesis, (1) the meteorological data and the behavioral and physiological responses of the animals were integrated in order to determine the benefits provided by the shade from the solar panels on the thermoregulation of the dairy heifers, and (2) measurements of the enteric methane emissions were taken to determine the potential of the solar panels to offset the GHG. Seven crossbred Holstein heifers (7/8, Holstein × Gyr) with a mean body weight of 242 kg (SD = 53.5) were evaluated in a paddock shaded with ten modules of solar panels. Miniature temperature loggers were used to record the body surface, skin and vaginal temperatures of the heifers every five minutes. The respiratory rate and the shade-use behavior were also monitored by two observers. These measurements were taken from 08:00 to 17:00 h for 18 consecutive days. After completing the field study, the heifers underwent for assessments of the daily oscillations of eCH4 emission using a flow-through respirometry system. The use of shade by the heifers was progressively increased (p < 0.01) with an increasing level of solar irradiance. Lying and ruminating were more likely (p < 0.01) to occur when the heifers were in the shade, especially when the solar irradiance exceeded 500 W m-2. Between 10:00 and 14:00 h, the heifers benefited from the shade produced by the solar panels, with a reduction of 40% in the radiant heat load. With an increasing intensity of solar irradiance, body surface temperature, skin temperature and respiratory rate of the heifers in the shade were lower (p < 0.01) compared to when they were exposed to the sun. The heifers had a daily methane emission total of 63.5 g per animal-1 or 1.7 kg of CO2-eq. Based on this emission rate and the amount of CO2-eq that was not emitted to the atmosphere due to the electricity generated by solar panels, 4.1 m2 of panels per animal (nominal power = 335 W) would be expected to obtain a net-zero eCH4 emission. Over a period of one year (from September 2018 to August 2019), a set of ten photovoltaic panels used in the study produced 4869.4 kWh of electricity, thereby saving US $970.00 or US $48.00 per m2 of solar panel. Based on the results of this study, it can be concluded that use of Animal Agrivoltaics, in addition to producing electricity, has significant potential benefit in providing better thermal comfort to cattle, as well as offsetting the enteric methane emissions released into the environment. In addition, the system would provide extra income to farmers, as well as a potential source of energy micro-generation.

Thermal comfort and behavior of beef cattle in pasture-based systems monitored by visual observation and electronic device

Understanding how the bioclimatic factors influence the animals homeothermy and behavior is essential to implement good practices for tropical livestock. Thus, the objective of this work was to study the effect of the incorporation of the arboreal component in pasture production systems in a tropical environment on thermal comfort and to analyze the influence of the integrated crop-livestock-forestry system on the behavior of beef cattle. The study was carried out in São Carlos-SP, Brazil, region of tropical altitude subtype, for 13 months. Sixty-four Nelore (Bos indicus) and Canchim (5/8 Bos taurus x 3/8 Bos indicus) non-castrated males (26 months; 358 kg LW) were allocated to production systems with pastures in full sun (Group FS; n = 32) or with forested pastures (Group ICLF; n = 32). The microclimate of the pastures was permanently monitored by weather stations. The behavior of the animals was assessed through an observational method in monthly campaigns and a continuous electronic monitoring method based on the use of an accelerometer and acoustic sensor coupled to collars. Higher means of the black globe temperature index were registered in the morning and the afternoon, with a very challenging condition for the animals during the spring and summers, especially for the Group FS. The observational results showed that animals in the Group FS grazed longer in the morning than animals in the Group ICL, mainly in the warmer seasons (P < 0.05). The animals in FS remained lying down longer than the animals kept in the ICLF system, during rumination or resting (P < 0.05). The animals in the Group ICLF preferred the use of shaded areas within the forested system and their frequency of visits to the drinking fountain was reduced in the morning (−55 %) and afternoon (−26 %) shifts. Electronic monitoring showed that animals, regardless of the production system, spent 38.4 % of their time resting, 32.6 % in displacement, and 29.0 % in rumination. The animals in FS had a higher displacement time at night and dawn, and less time resting at night (22:00 h and 23:00 h) and dawn (2:00 h to 6:00 h), which affected their circadian rhythm and restricted the time devoted to restorative effects of rest. Therefore, the use of the arboreal component proved to be beneficial for obtaining a more favorable microclimate for raising cattle on pasture, being useful for increasing animal thermal comfort and for the expression of behavioral attitudes favorable to the maintenance of homeothermy in a tropical environment.

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.

Animal thermal comfort index for the state of Paraíba, Brazil: trend, influencing factors, and mitigating measures

Animal thermal comfort index for the state of Paraíba, Brazil: trend, influencing factors, and mitigating measures

Thermal images to predict the thermal comfort index for Girolando heifers in the Brazilian semiarid region

The objective of this research was to use image analysis techniques to extract characteristics of interest and to establish a model of animal thermal comfort, based on the classification of thermal images of 7/8 Holstein-Gir heifers, through geostatistics and multivariate analysis. The thermal images were recorded by an infrared thermographic camera, which allowed images of the complete lateral faces of three heifers on pasture to be obtained. The analysis of the images consisted of the use of an extractor algorithm of notable points, referring to the regions of the head, neck, trunk, and limbs, to extract the matrices of the surface temperature of the animals. The temporal variability of the data was subjected to descriptive statistical analysis and spatial dependence, through geostatistics. The exploratory analysis of the data consisted of the application of the principal component analysis, in which 5 variables were admitted, head temperature (Thea, °C), cannon temperature (Tcan, °C), back temperature (Tbac, °C), udder temperature (Tudd, °C) and skin temperature (Tski, °C) of the animal, which allowed the identification of predictor variables correlated to animal comfort. The extraction of characteristics from the thermal images (06:00 am and 12:00 pm), using the ORB detector (Oriented fast and Rotated Brief), allowed to verification differences in the intensity of pixels in the images. The Gaussian model was the one that best fitted the studied variables and had a strong degree of spatial dependence (R2 > 0.900). The temperature of the head surface showed a greater variation (6 °C) between the analyzed times. PCA indicated a better correlation for Tcan, Tbac, Thea, and Tski in characterizing the thermal comfort of animals. The developed model proved to be efficient in characterizing the thermal comfort of heifers in the semiarid region, by determining the animal's surface temperature, with a smaller number of predictor variables.

Development and assessment of a low-cost embedded system for evaluation of animal thermal comfort

Technologically advanced animal production requires more controlled environments, aiming to maximize animal performance and, consequently, the profitability of the activity. To do that, it is necessary to instrument, evaluate and diagnose the various rearing environments. Hence, Precision Animal Production is inserted in this context and aims to effectively meet the general needs of the animal, so that it reach its full productive potential, correcting the divergences between the environment and its well-being to guarantee its comfort. Since Brazil is a country with tropical climate, which is a major obstacle, the proposal of this project is to develop a prototype for embedded system of thermal comfort analysis at low cost. Using sensors and the microcontroller Arduino to manage data, this work fulfilled its objective, with a prototype device (WGV-1c) capable of measuring dry bulb temperature, wet bulb temperature, black globe temperature, relative humidity, BGHI and THI with production cost below that proposed by the market.

Influence of microclimate on dairy cows’ behavior in three pasture systems during the winter in south Brazil

The aim of this study was to evaluate the influence of microclimate on thermal comfort and dairy cows' behavior in different pasture systems during the winter of a subtropical climate. The experiment was carried out in June and August 2020, covering the winter season in the southern hemisphere. Local microclimatic variables and cows' behaviors were compared in two conditions (shaded and sunny), in three pasture systems: silvopastoral system with disperse trees (SPSdisp), silvopastoral system with trees along the border fences (SPSfen), and treeless pasture (TLP). The black globe-humidity index (BGHI) was calculated to measure thermal comfort. During the afternoon the BGHI values were above animal thermal comfort at the sunny condition in the three pasture systems. The lowest average values (p<0.05) of BGHI and soil surface temperature were recorded in the SPSdisp and SPSfen when compared to TLP. The highest value of soil surface temperature observed in the three systems were: in the sunny condition of the SPSdisp (24.7°C) and SPSfen (23.1°C), both between 13:00-14:55; in the TLP (28.5°C) between 12:00-12:55. The time cows spent on each behavior was different (p<0.05) among the pasture systems and conditions (shaded and sunny): in both SPSs, cows spent more time lying (resting and rumination) at the sunny condition between 12:00-12:50, and more time standing (resting and ruminating) at the shaded condition between 13:00-13:50. The frequency of drinking water was approximately 33% greater in the TLP than in the SPSs when the BGHI exceeded the comfort threshold (12:00-12:50). In the silvopastoral systems the cows had the option to compensate the heat loss caused by low temperatures staying at the sun; they could also use shade when motivated to do so, either to seek protection from the sun in the middle of the day or to rest.

Spatiotemporal variations on infrared temperature as a thermal comfort indicator for cattle under agroforestry systems.

With the expanding use of thermal assessment techniques in beef cattle, infrared thermography has become a promising tool for assessing the environment for animal thermal comfort. Goals of this study were: (1) to evaluate cattle thermal comfort in agroforestry systems with different shade availability (2) to verify the spatiotemporal variations of infrared temperature inside agroforestry systems, and; (3) to test infrared thermography as a potential tool to assess animal thermal comfort indices in agroforestry systems. A trial was carried out between June 2015 and February 2016, covering Central-Brazil's dry winter and rainy summer seasons, respectively. The experimental area of Embrapa Beef Cattle is located in Campo Grande (Mato Grosso do Sul), coordinates 20°24'53″ S, 54°42'26″ W and 558m altitude. The 12ha plot has two agroforestry systems varying shade availability. Traditional Black Globe Temperature and Humidity Index, Heat Load Index and Radiation Thermal Load were determined, from measurements using digital thermo-hygrometers, with datalogger. Surface temperature and humidity of tree canopies and pasture were determined using an infrared thermographic camera. Results show spatiotemporal variations in infrared temperature. This means that the environment inside agroforestry systems is not homogeneously comfortable for cattle, and the system with the lowest shade availability has the greatest heat accumulation area. Weak to strong associations were identified between infrared variables and thermal comfort indices (0.08=r≤0.75). Positive relationships were also obtained and equally well explained by the Black Globe Temperature and Humidity Index and Heat Load Index (0.55=R2≤0.94). We conclude that infrared thermography can be used as a tool to assess thermal comfort indices in agroforestry systems and to determine onset of animal thermal stress from environment and heat body accumulation.

Study on Desiccant and Evaporative Cooling Systems for Livestock Thermal Comfort: Theory and Experiments

The present study considers evaporative cooling and desiccant unit-based air-conditioning (AC) options for livestock AC application. In this regard, proposed systems are investigated by means of experiments and thermodynamic investigations. Air-conditioning requirements for animals are theoretically investigated and temperature-humidity index (THI) is estimated. A lab-scale heat mass exchanger based on the Maisotsenko-cycle evaporative cooling conception (MEC) is set up and its performance is evaluated at different ambient air conditions. In addition, a desiccant-based air-conditioning (DAC) unit is thermodynamically evaluated using a steady-state model available in the literature. The study focuses on the ambient conditions of Multan which is the 5th largest city of Pakistan and is assumed to be a typical hot city of southern Punjab. The study proposed three kinds of AC combination i.e., (i) stand-alone MEC, (ii) stand-alone desiccant AC, and (iii) M-cycle based desiccant AC systems. Wet bulb effectiveness of the stand-alone MEC unit resulted in being from 64% to 78% whereas the coefficient of performance for stand-alone desiccant AC and M-cycle based desiccant AC system was found to be 0.51 and 0.62, respectively. Results showed that the stand-alone MEC and M-cycle based desiccant AC systems can achieve the animals’ thermal comfort for the months of March to June and March to September, respectively, whereas, stand-alone desiccant AC is not found to be feasible in any month. In addition, the ambient situations of winter months (October to February) are already within the range of animal thermal comfort.

CFD simulation of airflows and ammonia emissions in a pig compartment with underfloor air distribution system: Model validation at different ventilation rates

Pig buildings with underfloor air distribution (UFAD) system provide the animal area with efficient cooling and better air quality compared ceiling air inlets. This is because the air inlets near the floor and the exhaust opening at the ceiling allow the excess heat and the old air to be displaced from the animal area to the upper part of the building. Typical inlet types of UFAD systems in Flanders (Belgium) are the slatted floor units placed in service alley. The main drawback in pig buildings with UFAD systems is that during winter, cold draughts often occur in the animal area, and due to the air displacement ventilation process, there is a risk of NH3 transport from the slurry pit. The effect of NH3 emissions is important as it leads to acidification and eutrophication. Modelling airflows and NH3 emissions using Computational Fluid Dynamics (CFD) can promote the development of techniques for mitigating NH3 emissions, improving indoor air quality and animal thermal comfort. A steady-state CFD model was therefore developed to predict the indoor airflow and NH3 distribution in a pig compartment with a UFAD system. An advanced NH3 emission modelling approach was implemented in the CFD model to simulate NH3 generation in the slurry pit and pen floor. In order to validate the CFD model, two experiments were performed. The first experiment was conducted in a compartment with mock-up pigs at different ventilation rates to validate the modelled air velocity and temperature fields. The second experiment was conducted in a compartment occupied by real pigs to validate the modelled airflow patterns, temperature, CO2 and NH3 concentrations. Overall, there was a good agreement between the simulated and measured results. The field experiment and CFD model results confirmed that NH3 was transported from the slurry pit to the compartment. The air exchange rate of the slurry pit in the CFD model increased from 10.4 to 26.1 h−1 as the ventilation rate was increased from 11 to 92 m3 h−1 pig−1 due to the air displacement in the slurry pit.

Green Anaconda (Eunectes murinus) with Bacterial Clinical Stomatitis

Background: Stomatitis is an infectious disease common in serpents and responsible for high mortality rates. It is characterized by the infection of the oral mucosa and neighboring tissues, related to the opportunistic character of bacteria present in the normal microbiota, pathogenic in stressful situations. Few studies have described the profile of sensibility of these agents in serpents of the Brazilian fauna. Therefore, this study has aimed at describing the isolation and identification of the infectious agents involved in the clinic stomatitis in a specimen of green anaconda (Eunectes murinus), and the profile of susceptibility to antimicrobial agents.Case: The serpent has been rescued in an urban environment, without previous records and featured erosive injuries in its oral cavity, with the presence of secretion. In a clinical evaluation, it has been assessed that the specimen had erosive injuries in its oral cavity, with hyperemic points in its mucosa and serous secretion. Then the specimen went through a collection of the secretion from its oral cavity for microbiological analysis. Typical colonies of Enterococcus, Citrobacter and Enterobacter were identified by the colony morphology and their typical odor. The results of these tests were able to confirm and identify the Citrobacter freundii, Enterobacter spp. and Enterococcus spp. The profile of sensibility to antimicrobials of the isolated microorganisms has been determined through the method of diffusion in the disk of Kirby-Bauer. There was not any sensitive antimicrobial drug for the three agents.Discussion: Immunodepression, malnutrition, and temperatures and humidity outside the animal thermal comfort zone, are predisposing factors for the development of bacterial diseases in reptiles. Little information about pathogen agents affecting constrictor serpents in their native area is available. Most reports on stomatitis in serpents approach cases occurred in captive animals, differently from what has been presented in this case, which is about a free animal rescued when invading an urban area. The bacteria isolated from the oral cavity of the serpent here reported belong to the normal microbiota of the oral cavity of these animals. Notwithstanding, these bacteria may become pathogenic in certain circumstances. Conditions of undernutrition, stress and oral trauma are considered as predisposing factors to the occurrence of stomatitis in serpents, what can be correlated to the occurrence of the disease in this case. The gram-negative agents causing bacterial diseases in serpents are generally resistant to medicines of the most common spectrum used in the clinical routine of wild animals. This way, veterinarians often deal with these diseases in reptiles empirically, using a wide range of antibiotics. This practice might result in the development of resistant bacterial stumps, what stands out due to the potential that resistant bacteria have to generate infections and zoonoses in humans.

Temperature, thermal comfort, and animal ingestion behavior in a silvopastoral system

Thermal discomfort is one of the main causes of production losses in animals fully exposed to solar radiation under extensive livestock farming. The inclusion of trees in this farming system is the most efficient strategy to decrease the temperature and increase animal productivity without the need to explore new areas. In this context, the objective of this study was to characterize the microclimate in a silvopastoral system (SPS), a refuge area, and an open pasture, and evaluate thermal comfort and the ingestive behavior of animals under shade. The study was conducted at the Agronomic Institute of Paraná (IAPAR), located in Ibiporã, Paraná state, Brazil, in three areas with distinct management systems: a SPS of Eucalyptus grandis with Tifton 85 (Cynodon spp.), a woodland of Leucena leucocephala that provided shade to cattle, and a pasture in full sun (PFS). Automatic meteorological stations were installed in the SPS (one station beside the tree lines and the other in an average distance perpendicular to the rows), one in the refuge area, and one in the PFS. The measured variables were air temperature and relative humidity. The mean temperatures of the shaded treatments were compared to those of the PFS using a t-test. The mean values of the temperature and humidity index (THI) were calculated for each season of the year. The animal ingestion behavior in the SPS was analyzed in three typical days in different seasons of the year. Significant differences were observed between shade treatments and full-sun pasture, with a temperature decrease ranging from 0.4 to 1.6 °C in the shaded systems. The comparison of animal thermal comfort between the study areas in different seasons of the year indicated that there were no significant differences in thermal comfort between the SPS and refuge area relative to the PFS, suggesting a need to monitor the animals’ body temperature to better estimate thermal comfort. The evaluation of the ingestive behavior evidenced the animals’ preference to perform activities under tree shade and that the SPS led to changes in their food habits, optimizing grazing time. Therefore, the trees directly affected the microclimate of the studied environments, attenuating the temperature, protecting the animals against direct solar radiation, and providing better thermal comfort.

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.

ARTIFICIAL NEURAL NETWORKS FOR PREDICTING ANIMAL THERMAL COMFORT

ABSTRACT The objective of this study was to develop artificial neural networks (ANNs) for predicting animal thermal comfort based on temperature and relative humidity of the air for each day of the year. The data on temperature and relative humidity for a 25-year historical series collected at the Padre Ricardo Remetter Conventional Meteorological Station, located in the city of Santo Antonio de Leverger - Mato Grosso (Brazil), were retrieved from the website of the National Institute of Meteorology. According to the day of the year, the temperature and humidity index was determined as a function of the climatic variables. Therefore, the day of the year was the input variable of the neural networks, and the temperature and humidity index (THI) was the output variable. The number of layers and neurons used for establishing different architectures was variable. Data were adjusted on the basis of mean square errors, performance and efficiency indexes, and normality tests. The values estimated by the networks and those obtained from the historical series did not differ significantly. The networks with the best performance were selected for graphical analysis of residuals. The ANNs developed in this study predicted animal thermal comfort with adequate reliability and precision.

Association between human and animal thermal comfort indices and physiological heat stress indicators in dairy calves

Warm summer episodes have a significant effect on the overall health and well-being of young cattle; however, it is not known which temperature measure should be used for estimating heat stress in dairy calves. In this study, generalized linear mixed-effects models were used to estimate the relationships between thermal comfort indices and animal-based heat stress indicators in sixteen Holstein bull calves that were housed in individual calf hutches. Data were collected under continental weather characteristics over a 5-day period: day 1 (lower-temperature day), days 2 and 3 (heat stress days), and a 2-day post-stress period. Relative humidity, ambient temperature, the heat index, the humidex and five different temperature–humidity indices (THI) were used as thermal indices. Physiological variables monitored included respiratory rate, rectal temperature, ear skin temperature and heart rate. The heat index and the humidex measuring human thermal comfort were more closely associated with physiological measures than were the ambient temperature or the THIs (in case of heat index: R2 = 0.87 for respiratory rate, R2 = 0.63 for rectal temperature, R2 = 0.70 for ear skin temperature, and R2 = 0.78 for heart rate, respectively; in case of humidex: R2 = 0.85 for respiratory rate, R2 = 0.60 for rectal temperature, R2 = 0.68 for ear skin temperature, and R2 = 0.75 for heart rate, respectively). Based on our results, parameters of human outdoor comfort seem better to estimate heat stress in dairy calves in a continental region than those of THIs or ambient temperature.

English

This research aimed to evaluate the dendrometric development of four tree species (Carapa guianensis Aubl. (Meliaceae); Dipteryx odorata (Aubl.) Willd (Fabaceae), Swietenia macrophylla King (Meliaceae) and Handroanthus chrysotrichus (Mart ex A. DC.) Mattos (Bignoniaceae)) in a silvopastoral system in Santarem, Para, Brazil. Productive activities in the forest sector create a demand for technical capacity to promote sustainable management, with the silvipastoral system presented as one of the paths to sustainability. Three permanent plots of 1 ha each were established on the 240-hectare Diamantino Farm, and stem DBH 1.30 m from the soil surface, total height and crown diameter data were obtained for all individuals. In addition to the quantitative data, crown regularity and bole tortuosity parameters were measured. S. macrophylla achieved better performance in almost all parameters. C. guianensis and D. odorata, respectively showed greater uniformity in growth. The species, H. chrysotrichus had the smallest crown diameter; however it was still able to provide enough shade for animal thermal comfort. Key words: Dendrometry, forest management, reforestation.

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.

Dermatopathy Caused by Enterobacter aerogenes and Pseudomonas aeruginosa in Boa constrictor amarali

Background: Bacterial diseases are the main cause of the high mortality rates of snakes, especially those caused by gramnegative agents. However, studies on dermatopathy caused by these bacterial agents in snakes are scarce; and no reports have been found on Enterobacter aerogenes as causative agent of dermatopathy in snake species. Thus, the objective of this study was to describe the clinical signs, and lesion evolution of a dermatopathy in a male snake (Boa constrictor amarali) specimen of approximately seven years old; and to describe the isolation and identification of the Enterobacter aerogenes and Pseudomonas aeruginosa agents involved in the cause of this disease.Case: The Boa constrictor amarali evaluated presented blackened cutaneous lesions in the dorsal, snout-vent and tail regions; and well-defined subcutaneous nodules of 2.0-3.0 cm diameter, with soft consistency, reddish color, cutaneous flaccidity, and areas of scale ulceration in the dorsolateral region. The clinical evaluation of the animal showed dehydration signs and pale mucous membranes. The blackened lesions were subjected to mycological analysis - after procedure of deep scale scraping - which showed presence of septate hyphae. The nodule was punctured for microbiological and biochemical analysis. The sample was collected with a sterilized alginate cotton tip swab, and was stored in a plastic tube containing a semi-solid Stuart transport medium, for microbiological analysis. Then, this sample was incubated in a bacteriological oven at 37°C for 24 h. Typical colonies of Pseudomonas and Enterobacter grew on MacConkey agar medium; these bacteria were identified by the colony morphology and their typical odor. The colonies grown in MacConkey agar were also identified through biochemical tests in the mediums: Phenol red, Lysine, Phenylalanine, Citrate, Urea and SIM (Sulfide, Indole, Motility). The results of these tests were able to confirm and identify the P. aeruginosa and E. aerogenes species. The animal died within 36 h, before the identification of the causative agents of the disease, thus, no pharmacological interference was possible.Discussion: Immunodepression, malnutrition, and temperatures and humidity outside the animal thermal comfort zone, are predisposing factors for the development of bacterial diseases in reptiles. Little information about pathogen agents affecting Boa constrictor specimens in their native area is available; however, captive snakes are subject to a wide variety of diseases - most of which caused or intensified by the captivity conditions. Among the bacteria involved in reptile diseases, few are primary causative agents. In general, clinical bacterial infections tend to be secondary to viral infections. The bacterial agents found in this study are commonly described in scientific literature with location in the oral cavity, differently from the results found in this study. Moreover, the bacterium E. aerogenes has not yet been described in other studies as a causative agent of dermatopathy. Reptiles are considered reservoirs of important zoonotic microorganisms, such as P. aeruginosa, which can be transmitted by fecal contact, bites and wounds. However, the little information on P. aeruginosa in captive reptiles indicates the need for further studies to establish its zoonotic potential. A most adequate management conditions for the snake species could have decreased the severity of the lesions. The occurrence of P. aeruginosa and E. aerogenes found in this work may alert professionals for future clinical suspicions and adequate therapeutic management.

Can meteorological variables affect milk production in different lactation orders of dairy cows in the Cfb climatic zone? A case study in Southern Brazil.

Data from 5689 lactating cows in 35 different dairy herds in Southern Brazil were evaluated over a 15-year period to examine the influence of meteorological variables on milk production in dairy cows with primiparous (1st) and multiparous (2nd to 4th) lactation. Meteorological variables considered were maximum and minimum temperature, relative humidity of air, solar radiation, wind speed, precipitation and temperature and humidity index corrected for solar radiation and wind speed (THIc). Data were submitted to principal component analysis (PRINCOMP), Pearson correlation (CORR) and step-by-step (STEPDISC) discriminant analyses, using the Statistical Analysis System (SAS®). lactation order and milk production showed a negative and significant correlation with minimum temperature, but with low magnitude. Primiparous and multiparous cows were negatively affected by maximum temperature in summer, while the higher the minimum temperature in winterwas, the better the milk production was. Primiparous cows produced, on average, 28.17 kg/day of milk and were 26.15 months old while the multiparous cows in average produced 30.76 kg/day and were 54.47 months old. The greatest average maximum temperature recorded during the 15 years of observations did not exceed 30oC and the THI corrected were maintained within acceptable values for animal thermal comfort. Lactation order and milk production showed a negative and significant correlation with minimum temperature, but with low magnitude. Milk production of multiparous cows was negatively affected by maximum temperature in summer and milk production of both categories were affected negatively by minimum temperature in fall. The principal component analysis did not show any association between milk production, lactation order and meteorological variables. Discriminant analysis presented significant values for meteorological variables, but with very low values of partial R2 estimated. Meteorological variables in a Cfb climatic zone did not negatively affect milk production in primiparous and multiparous lactating cows.