Infrared thermography for evaluation of the environmental thermal comfort for livestock

Application of Infrared Thermography in the Rehabilitation of Patients in Veterinary Medicine

Infrared Thermography (IRT) has become an assistance tool in medicine and is used to noninvasively evaluate heat elimination during and after inflammatory processes or during the recovery period. However, its application in veterinary patients undergoing physiotherapy is a field that requires deep research. This review aims to analyze the application of IRT in the monitoring of animal physiotherapy, using the thermal changes that are present in patients undergoing gait or lameness issues (e.g., inflammation, pain, increased local temperature) as a neurobiological basis. Rehabilitation techniques such as acupuncture, physical therapies, thermotherapy, photo-biomodulation, and electrostimulation have been reported to have an anti-inflammatory effect that decreases the amount of local heat production, which is heat that can be recorded with IRT. Therefore, IRT could be used as a complementary tool to evaluate the effectiveness of the therapy, and it is suggested that further studies evaluate the accuracy, sensibility, and sensitivity of IRT.

Vaginal temperature modeling in Holstein cows and cluster analysis by the cophenetic correlation coefficient

The objective was to establish a model for the prediction and characterization of vaginal temperature in Holstein cows, based on environmental predictors and thermal comfort indices, through cluster analysis, validation by the cophenetic correlation coefficient, and multiple regression analysis. The micrometeorological characterization of the site was carried out by recording the air temperature (T_air), the relative humidity (RH), the black globe temperature (BGT), the black globe temperature and humidity (BGHI), and dew point temperature (TDP). The recording of vaginal temperature (Tv) was performed in eight dairy cows using temperature sensors, equipped with data loggers, coupled with intravaginal devices. The data were analyzed using descriptive statistics and cluster analysis (CA) by using the hierarchical agglomerative method based on the value of the cophenetic correlation coefficient (CCC >0.70), in which representative physiological models were established, characterizing the Tv through multiple regression. In the afternoon the coefficient of variation (CV) was low for all variables, indicating homogeneity of the meteorological variables and efficiency of the ventilation system. The temperature and humidity index (THI) was mild only on the morning. There was a variation of 0.28 °C of Tv between shifts, sufficient to characterize the condition of comfort and stress of the animal, with values above 39 °C indicating animal stress. Tv showed strong correlation with BGT, T_air, TDP and RH, assuming that physiological variables, such as Tv, tend to have greater relationship with abiotic variables. Empirical models were established for estimating Tv based on the analyses performed in this study. Model 1 is recommended for TDP ranges of 14.00-21.00 °C and RH of 30-100%, while model 2 can be used for T_air situations up to 35 °C. The regression models for estimating Tv are promising for characterizing the thermal comfort of dairy cows housed in compost barn systems.

Feather Damage Monitoring System Using RGB-Depth-Thermal Model for Chickens

Feather damage is a continuous health and welfare challenge among laying hens. Infrared thermography is a tool that can evaluate the changes in the surface temperature, derived from an inflammatory process that would make it possible to objectively determine the depth of the damage to the dermis. Therefore, the objective of this article was to develop an approach to feather damage assessment based on visible light and infrared thermography. Fusing information obtained from these two bands can highlight their strengths, which is more evident in the assessment of feather damage. A novel pipeline was proposed to reconstruct the RGB-Depth-Thermal maps of the chicken using binocular color cameras and a thermal infrared camera. The process of stereo matching based on binocular color images allowed for a depth image to be obtained. Then, a heterogeneous image registration method was presented to achieve image alignment between thermal infrared and color images so that the thermal infrared image was also aligned with the depth image. The chicken image was segmented from the background using a deep learning-based network based on the color and depth images. Four kinds of images, namely, color, depth, thermal and mask, were utilized as inputs to reconstruct the 3D model of a chicken with RGB-Depth-Thermal maps. The depth of feather damage can be better assessed with the proposed model compared to the 2D thermal infrared image or color image during both day and night, which provided a reference for further research in poultry farming.

Thermoregulation mechanisms and perspectives for validating thermal windows in pigs with hypothermia and hyperthermia: An overview

Specific anatomical characteristics make the porcine species especially sensitive to extreme temperature changes, predisposing them to pathologies and even death due to thermal stress. Interest in improving animal welfare and porcine productivity has led to the development of various lines of research that seek to understand the effect of certain environmental conditions on productivity and the impact of implementing strategies designed to mitigate adverse effects. The non-invasive infrared thermography technique is one of the tools most widely used to carry out these studies, based on detecting changes in microcirculation. However, evaluations using this tool require reliable thermal windows; this can be challenging because several factors can affect the sensitivity and specificity of the regions selected. This review discusses the thermal windows used with domestic pigs and the association of thermal changes in these regions with the thermoregulatory capacity of piglets and hogs.

The potential of natural shade provided by Brazilian savanna trees for thermal comfort and carbon sink

This study looked at the potential of thermal comfort provided to animals by four different Brazilian savanna (Cerrado) native trees, as well as their potential for carbon sink. The evaluations were carried out during the summer of 2020, which consisted of the collection of microclimate variables. The Mean Radiant Temperature (TMR, °C) was derived from the shaded and unshaded areas under the trees, and from that, the Radiant Heat Load (RHL, W m^-2) was calculated as an index of thermal comfort. Solar radiation was estimated considering the sum of the direct, diffuse, and reflected components (W m^-2), and carbon stock from trees biomass for CO₂ sequestration was estimated from an allometric model applied to the native Cerrado tree species. The shade of the native trees reduced the meteorological variables such as dry bulb and black globe temperatures, to values considered adequate for the thermal comfort of animals, with an average reduction respectively equal to 1.3 °C and 6.4 °C. This represents a significant difference compared to the unshaded area as well as among tree species (P < 0.05), reflecting in lower values of TMR and RHL in the shaded area provided by each species. Carbon sequestration individually estimated by each native tree species was on average 8.85 Mg per tree. These results demonstrate the great potential for native tree species in the Cerrado biome to be used in agroforestry systems to provide higher levels of thermal comfort to animals and to combat climate change through their aptitude of CO₂ sink.

Progress on Infrared Imaging Technology in Animal Production: A Review

Infrared thermography (IRT) imaging technology, as a convenient, efficient, and contactless temperature measurement technology, has been widely applied to animal production. In this review, we systematically summarized the principles and influencing parameters of IRT imaging technology. In addition, we also summed up recent advances of IRT imaging technology in monitoring the temperature of animal surfaces and core anatomical areas, diagnosing early disease and inflammation, monitoring animal stress levels, identifying estrus and ovulation, and diagnosing pregnancy and animal welfare. Finally, we made prospective forecast for future research directions, offering more theoretical references for related research in this field.

Technological opportunities for sensing of the health effects of weather and climate change: a state-of-the-art-review

Sensing and measuring meteorological and physiological parameters of humans, animals, and plants are necessary to understand the complex interactions that occur between atmospheric processes and the health of the living organisms. Advanced sensing technologies have provided both meteorological and biological data across increasingly vast spatial, spectral, temporal, and thematic scales. Information and communication technologies have reduced barriers to data dissemination, enabling the circulation of information across different jurisdictions and disciplines. Due to the advancement and rapid dissemination of these technologies, a review of the opportunities for sensing the health effects of weather and climate change is necessary. This paper provides such an overview by focusing on existing and emerging technologies and their opportunities and challenges for studying the health effects of weather and climate change on humans, animals, and plants.

Using infrared thermography to detect subclinical mastitis in dairy cows in compost barn systems

This study aimed to evaluate the use of thermal imaging obtained by infrared thermography (IRT) to detect cases of subclinical mastitis in dairy cows under commercial conditions of compost barn systems in a region of Brazil with a semiarid climate. Twenty-eight crossbred cows were evaluated twice a day for one week using IRT. Three thermal images were obtained for each cow, referring to the anatomical regions of the right and left fore udder and rear udder. A computer program was used to analyze the images and obtain the right fore udder temperature (RFUT, °C), left fore udder temperature (LFUT, °C), rear udder temperature (RUT, °C), and average udder temperature (AUT, °C). In addition, samples of milk from each quarter of the udder were collected for somatic cell count (SCC) to correlate the diseases observed on the thermal image with any infection in the udder region. The results obtained using IRT were subjected to regression and correlation analyses. It was observed that LFUT, RAQT, RUT, and AUT were adjusted in quadratic polynomial models with good prediction of SCC (i.e., infection) with R² = 0.92, 0.97, 0.86, and 0.94, respectively. The region of the anterior quarters of the udder was the most promising for imaging, stronger correlations were obtained between LFUT and RFUT with SCC (r = 0.87 and 0.88, respectively). The IRT is a practical technology capable of detecting cases of mastitis in dairy cows with good precision, especially with thermal images from the anatomical region of the front quarters of the udder. However, more detailed studies are needed to make thermal imaging processing a more useful method for routine activities on farms in compost barn systems.

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 558 m altitude. The 12 ha 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.

Different methods of assessing udder temperature through thermography and their relation with rectal temperature

Infrared thermography of the lateral side portion of the udder was taken from 38 lactating cows in a 6-day experiment. Thermograms were analyzed using specific software with the use of eight different methods. The experiment was aimed at correlating the different methods with each other and with rectal temperature (RT), in order to suggest a method to assess udder side temperature, and also at creating regression equations to enable RT calculation through the use of thermographic data. All methods of analyzing thermograms were highly correlated; correlations between thermograms and RT were significant (P < 0.01) and above 0.840. The highest correlation was between RT and the maximum temperature obtained using a horizontal rectangle placed within the lateral (side) portion of the udder (maximum temperature in a horizontal rectangle (MHR), 0.897). With the exception of the average temperature of a horizontal rectangle, linear regression coefficients were significant (P < 0.05) and coefficients of determination were higher than 75.51%. We suggest the use of MHR to evaluate udder side temperature. The ease of accessing the side of the udder, the welfare advantages of non-invasive observations, and the high correlation with RT suggest the use of thermograms in the lateral portion of the udder to assess animals' temperature.