Thermographic evaluation of climatic conditions on lambs from different genetic groups

Abstract

In production systems the characterization of genetic resources in relation to their capacity to respond to environmental conditions is necessary. The objective of this study was to evaluate the use of infrared thermography for separation of animals from different genetic groups and determine which phenotypic traits are important for climatic adaptation. A total of 126 suckling lambs from four different genetic groups (Santa Inês--SI, Bergamasca--B, Bergamasca X Santa Inês--BS, and Ile de France X Santa Inês--IL) were used. The animals were divided into two groups, one housed and another in an outside paddock. Thermograph photographs were taken at four-hour intervals over three full days. Temperatures of the nose, skull, neck, fore and rear flanks and rump were measured, as well as coat depth, the density and length of hairs, reflectance and color. The daily temperature range during the experimental period was more than 20°C, with animals experiencing heat (12 h to 15 h) and cold (24 h to 4 h) stress. The three main phenotypic traits that influenced genetic group separation were hair density, height of coat, and length of hairs. Thermograph temperatures were able to detect different responses of the genetic groups to the environment. Therefore, infrared thermography is a promising technique to evaluate the response of animals to the environment and to differentiate between genetic groups.

Heat tolerance in Brazilian hair sheep

“…In this study, high THI was observed in the afternoon, reaching values classified as danger and emergency [17]. This high amplitude of thermal variation observed in the present study have already been reported in the Midwest region of Brazil, where animals tend to suffer from cold stress at night and heat stress during the day [19]. The animal’s ability to respond to heat stress depends upon exposure to low temperatures during the night, and more specifically, the duration and intensity of this low temperature [9].…”

“…Infrared thermography has been shown to be related to several physiological processes associated with heat tolerance [19,29]. In the present study, the thermographic temperatures of the several body areas measured using an infrared camera were affected by period of the day and, as expected, were lower in the morning period with cooler environmental temperatures.…”

“…A relationship between time of day and foot temperature have also been reported in Comisana sheep kept under a natural photoperiod [30]. Body temperature variation that increased throughout the day and decreased at night had also been reported by several researchers [19]. This variation was probably due to the lower thermal balance between the surface of the animal and the air temperature in the afternoon.…”

“…In a thermographic evaluation of climatic conditions on lambs, the temperature of the nose was the only one that behaved differently [19]. However, here this thermographic temperature was grouped with the others.…”

Applicability of Ammonia Sensors for Controlling Environmental Parameters in Accommodations for Lamb Fattening

“…Alternatively, environmental parameters could be bypassed entirely in favour of measuring the body temperature of animals-after all, this factor is a direct cause of thermal stress. Contact thermometers, infrared thermometers, and thermal lamps are all potential methods [10,14,15]; however, these types of measurements are challenging, expensive, and difficult to automate.…”