Estimation of Respiratory Frequency and Rectal Temperature on Pigs in Heat Stress by Fuzzy Logic

Abstract

Physiological parameters such as respiratory frequency and rectal temperature stand out as indicators for heat stress in pigs, however, requiring time and labor for measurements. The possibility of using infrared thermography associated with prediction systems of these physiological variables can help in decision making, allowing greater welfare and productivity of the animals. With this objective, an experiment was carried out with growing pigs submitted to acute and chronic heat stress, working with a thermoneutrality temperature (22° C) and heat stress (34° C). The results were used for the development of a fuzzy model using as input variables: air dry bulb temperature (°C), average surface temperature (°C) and, as output variables: respiratory frequency (movements/minute) and rectal temperature (°C). The method of inference used was the one of Mamdani having been elaborated six rules and the defuzzification technique used was the one of the Center of Gravity. In the obtained results on simulation model when compared with experimental data was evidenced satisfactory efficiency in respiratory frequency determination and the rectal temperature, in which the R 2 values calculated were respectively 0.997 and 0.951 for acute stress and 0.993 and 0.964 for chronic heat stress.

Use of Different Cooling Methods in Pig Facilities to Alleviate the Effects of Heat Stress—A Review

“…The authors also found that average skin-surface temperature increased from 33.5 °C to 40.5 °C, but in contrast to the body-core temperature, it dropped when the animals were moved back to the thermal neutral conditions. In turn, de Oliveira et al [ 27 ] studied both effect of acute (48 h) and chronic stress (71 d) on finishing pigs. Short-term heat stress caused an increase of 0.6 °C in rectal temperature; in turn pigs’ exposure to heat for a longer period was characterised by a body core temperature 0.2 °C higher than normal values.…”

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

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