Black Globe Temperature Humidity Research Articles

Passive envelope solutions to aid design of sustainable livestock buildings in Mediterranean climate

The dairy cattle sector is responsible of significant greenhouse gas emissions such as methane, carbon dioxide, nitrous oxide. The reduction of heat stress of dairy cows plays a crucial role in the improvement of dairy productivity and avoid greenhouse emissions. In this study a parametric analysis about several traditional or innovative passive solutions for building envelope of livestock housing is carried out, with the aim to achieve the thermal comfort of animals without active energy systems.The different energy efficiency measures designed for the building envelope are evaluated on the basis of different indexes for animal comfort, by means of the combination of the Building Energy Performance Simulations (BEPS) and computational fluid dynamics (CFD) simulations.The proposed method starts from the numerical model definition of a semi-closed, naturally ventilated, loose housing system, characterized by criteria traditionally recognized or accepted by the scientific community for designing a dairy cow housing. Different interventions, referred to the shape of the building and its envelope materials, are taken into account, such as cool materials or cross laminated timber, as well as polyurethane insulation or shading systems.Basing on the both temperature-humidity index (THI) and black globe temperature humidity index (BGHI) the optimal building envelope solutions are: opening ridge area with 1.8 m width, window to wall ratio equal to 79%, roof made by polyurethane foam with a slope of 15°. The environmental indexes calculated by means of BEPS numerical models simpler than CFD analysis bring a difference in results by a maximum of 18%.The results can support the decision-making process in the design of a sustainable barn for dairy cows taking animals welfare as reference. Moreover, the methodological approach could be easily replicated for other livestock type or other climatic zones.

Ingestive Behavior and Physiological Parameters of Sindhi Heifers Receiving Saline Water

The objective was to evaluate the effects of potential use of brackish water as a source for Sindhi heifers on ingestive behavior and physiological and serum parameters. Twenty-four Sindhi heifers were distributed in a completely randomized design with four treatments and six replications, with levels of total dissolved solids (TDS) of 640, 3200, 5760, and 8320 mg/L. Three 24-hour behavioral tests were performed, which were divided into four observation shifts (00:00 to 06:00; 06:00 to 12:00; 12:00 to 18:00 and 18:00 to 00:00) at the beginning, middle, and end of the experiment. The highest values of black globe temperature humidity index and air temperature were observed at 14:00 h, with values of 92.7 and 34.1 °C, respectively. The different levels of TDS did not promote significant differences (P > 0.05) in the variables feed intake, rumination, idling, feeding efficiency as a function of dry matter and neutral detergent fiber intake, rumination efficiency as a function of dry matter and neutral detergent fiber intake, heart rate, rectal and surface temperature, creatinine, and potassium. Among the assessed shifts, feed and water intake showed higher frequencies in the shifts 2 (06-12 h) and 3 (12-18 h) and rumination showed a higher frequency in the shifts 1 (00-06 h) and 4 (18-00 h). The physiological variables presented higher indices during the warmest hours of the day. A linear behavior was observed for the serum sodium level, presenting a average of 134.4 mmol/L. Water containing up to 8,326 mg/L TDS can be used in the watering of Sindhi heifers in short periods in the season of highest water shortage without affecting the ingestive behavior and physiological and serum parameters of the animal.

Thermoregulatory responses of sindhi and guzerat heifers under shade in a tropical environment

This study characterized the thermal environment and assessed the physiological aspects of acclimatization of Sindhi and Guzerat heifers in a tropical environment (Brazil) under shade. Eight Sindhi and eight Guzerat purebred heifers (Bos indicus) had their physiological traits measured twice a day (9:00 a.m. and 2:00 p.m.). Environmental data during the experimental period were collected at two-hour intervals between 5:00 a.m. and 5:00 p.m. The temperature-humidity (THI) and the black globe temperature-humidity (BGHI) indices were calculated, and surface temperature (St), respiratory rate (Rr), and rectal temperature (Rt) were collected, being used to estimate heat loss by cutaneous (Ec) and respiratory (Er) evaporation. In the warmer parts of the day (1:00 and 3:00 p.m.), the THI and BGHI reached values of 80.26 and 81.25, respectively. There was no significant difference in rectal temperatures between the breeds, but higher values were observed in the afternoon. Heat transfer by cutaneous evaporation reached 118.71±12.91 W.m-2 and 103.43±6.82 W.m-2 at 2:00 p.m. for the Sindhi and Guzerat heifers, respectively. Under these conditions (air temperature was between 29 and 30°C), 84% of the total latent heat loss in Sindhi and Guzerat heifers was represented by Ec. It can be concluded that Sindhi and Guzerat heifers can maintain homeothermy with minimal thermoregulatory effort under shade conditions in a tropical environment.

Tolerância ao Calor em Ovinos de Pelames Claro e Escuro Submetidos ao Estresse Térmico

The aim of this research was to evaluate heat tolerance of thirty crossbred sheep (Santa Ines with Dorper) with white and black coat under heat stress. The experiment was conducted in September and October of 2012 and a completely randomized design was used. Before and after one hour exposure to solar radiation (14h00 - 15h00), rectal temperature, respiratory rate and surface temperature of the animals were measured. The Black Globe Temperature Humidity Index, the Heat Tolerance Index and the Heat Tolerance Coefficient were calculated. The values found for the Black Globe Temperature Humidity Index in the sun and in the shade were 89.08 and 82.81 respectively. Animals coat coloring did not influence on their rectal temperature and there was no difference on the heat tolerance index. It was verified the effect of coat coloring on the respiratory rate in dark colored hair coat sheep (P < 0.05) and the effect of the environment and coat coloring on the surface temperature and on the heat tolerance coefficient under the sun. Dark colored hair coat sheep presented lower heat tolerance.

Determinação dos Parâmetros Fisiológicos e Gradientes Térmicos de Caprinos Jovens Anglo-Nubianos no Semiárido Brasileiro

The aim of this research was to evaluate the thermal gradients of Anglo nubian goatling fed artificially and maintained under the same environmental conditions in semiarid. Were used 22 goatling aged 90 days and in this experiment a completely randomized design was used. The rectal temperature, respiratory rate and the surface temperature of the animals were measured. The thermal characterization of the environment was realized, through the Black Globe Temperature Humidity Index. The thermal gradients were evaluated by the difference between the rectal temperature and surface temperature (TRTS) and the difference between the surface temperature and the ambient temperature (TSTA). The values found for the Black Globe Temperature Humidity Index were 79.37 °C and for the thermal gradients were 3.6 °C and 5.3 °C for TRTS and TSTA respectively. The Anglo-nubian goatling showed good adaptability to semi-arid region.

Grazing Management and Microclimate Effects on Cattle Distribution Relative to a Cool Season Pasture Stream

Abstract Because of concerns about the impact of grazing management on surface water quality, a 3-yr study was conducted to determine grazing management and microclimate impacts on cattle distribution relative to a pasture stream and shade. Three treatments, continuous stocking with unrestricted stream access (CSU), continuous stocking with restricted stream access (CSR), and rotational stocking (RS), were evaluated on six 12.1-ha cool-season grass pastures stocked with 15 fall-calving Angus cows ( Bos taurus L.) from mid-May through mid-October of each year. On 2 d · mo −1 from May through September of each year, a trained observer in each pasture recorded cattle position and activity every 10 min from 0600 to 1800 hours. In years 2 and 3, position of one cow per pasture was recorded with a Global Positioning System (GPS) collar at 10-min intervals 24 h · d −1 for 2 wk · mo −1 from May through September. In week 2 of collar deployment in May, July, and September, cattle had access to off-stream water. Ambient temperature, black globe temperature, relative humidity, and wind speed were recorded at 10-min intervals and temperature humidity (THI), black globe temperature humidity (BGTHI), and heat load (HLI) indices were calculated. Based on GPS collars, mean percentage of time cows in CSU pastures were in the stream (1.1%) and streamside zone (10.5%) were greater ( P P