Thermal comfort index and infrared temperatures for lambs subjected to different environmental conditions

Abstract

There is an abundance of thermal indices with different input parameters and applicabilities. Infrared thermography is a promising technique for evaluating the response of animals to the environment and differentiating between genetic groups. Thus, the aim of this study was to evaluate superficial body temperatures of lambs from three genetic groups under different environmental conditions, correlating these with thermal comfort indices. Forty lambs (18 males and 22 females) from three genetic groups (Santa Inês, Ile de France × Santa Inês and Dorper × Santa Inês) were exposed to three climatic conditions: open air, housed and artificial heating. Infrared thermal images were taken weekly at 6h, 12h and 21h at the neck, front flank, rear flank, rump, nose, skull, trunk and eye. Four thermal comfort indices were calculated using environmental measurements including black globe temperature, air humidity and wind speed. Artificial warming, provided by infrared lamps and wind protection, conserved and increased the superficial body temperature of the lambs, thus providing lower daily thermal ranges. Artificial warming did not influence daily weight gain or mortality. Skin temperatures increased along with increases in climatic indices. Again, infrared thermography is a promising technique for evaluating thermal stress conditions and differentiating environments. However, the use of thermal imaging for understanding animal responses to environmental conditions requires further study.

Relación de temperatura rectal y frecuencia respiratoria con temperaturas de pelo obtenidas por termografía en ovejas gestantes estresadas por calor

“…Al igual que en este estudio, otras investigaciones plantean el uso de las cámaras termográficas como un método alternativo no invasivo para evaluar el estrés calórico en ovinos (Paim et al, 2014;McManus et al, 2015;Vicente-Pérez et al, 2016;Macías-Cruz et al, 2016) y otras especies (Martello et al, 2010). Las imágenes térmicas captadas por estas cámaras permiten determinar la temperatura de diferentes superficies de pelo, las cuales pueden ser usadas para desarrollar modelos de predicción al estar correlacionadas con TR y FR (McManus et al, 2016), tal como en el presente estudio fue demostrado.…”

“…Estas imágenes permiten determinar la temperatura de la superficie de diferentes regiones corporales del animal, y relacionar dichas temperaturas con aspectos productivos, reproductivos y de salud animal (Luzi et al, 2013). Al ser la termografía infrarroja un método no invasivo, algunos estudios recomiendan el uso de imágenes termales como indicativo de estrés calórico en ovinos, considerando que hay una asociación positiva entre variables fisiológicas como TR y FR con temperaturas de la capa de pelo o lana obtenidas por termografía infrarroja (Castanheira et al, 2010;George et al, 2014;Paim et al, 2014;Vicente-Pérez et al, 2016).…”

Use of Infrared Thermography for Identifying Physiological and Hematological Conditions of Young Sapera Dairy Goats

“…Fluctuations in rectal temperature and respiration rate across the observation time were also investigated by Hooper et al (2018) with the lowest value occurred at 6 a.m. morning. Several studies (Paim et al 2014;McManus et al 2015;Seixas et al 2017) reported that the lowest temperatures occurred in the morning and reached its peak at noon.…”

Shade Modifies Behavioral and Physiological Responses of Low to Medium Production Dairy Cows at Pasture in an Integrated Crop-Livestock-Forest System

“…Some studies have shown that long hair can be a heat insulator, serving as a buffer between the environment and the animal’s body [ 30 , 31 ]. An important point to note here is that, in the dry season, although the temperature is high during the day, it can fall well below 10 °C at night [ 32 , 33 ], as skies in this region at this time of year do not have cloud cover, so a lot of heat is lost from the earth’s surface by radiation. While Girolando cows contain Bos taurus taurus genes, and therefore may show a higher resistance to these colder temperatures, Gyr ( Bos taurus indicus) do not have an adaptation to low temperatures [ 34 ].…”