Estimation of Rectal Temperature of Goats Based on Surface Temperature

Abstract

Infrared thermography (IR) is a non-invasive tool with potential to indicate changes in the animal's thermal conditions in response to the thermally stressful environment. The objective of this study was to evaluate the application of IR to estimate the rectal temperature of crossbred goats of the Boer breed. Six male crossbred goats of the Boer breed were distributed in a completely randomized design and submitted to temperatures of 26, 30 and 34 °C and 68% relative humidity. Rectal temperature (RT) and thermograms data were collected from animals at each air temperature (AT) evaluated. In the thermograms, the temperatures of the ocular globe (PT), head (HT), shoulder (ST), hindquarter (HQ) and maximum infrared (IRMax) temperatures of the animals' surfaces were collected. The correlation of PT, HT, ST, HQ and IRMax data with RT was evaluated through the Pearson coefficient analysis and the concordance using Bland-Altman diagrams. With the exception of the IRMax surface temperature, the others were adequate for the accurate estimation of RT, with PT standing out for presenting the highest correlation coefficient with RT (r = 0.951) and estimation errors varying in the range of ± 0.27 °C.

Thermoregulation in Sheep and Goats: A Review

“…In most cases, animals exposed to heat stress tend to have an elevated core body temperature, breathing rate, heart rate, changing endocrine function, sweating, and metabolic activity [7,16,47,48]. According to Marques [49], an increase in the goats' core temperature from 38.0 0 C to 39.0 0 C indicates that the animal has been kept at a hot ambient temperature for more than six hours. Another study by Al-Dawood [50] reported that an increase in rectal temperature above 44 0 C indicates that the animal has been exposed to higher temperatures.…”