Performance of growing pigs subjected to lighting programs in climate-controlled environments

Janice M C Barnabé,José L S Carvalho Filho,Mônica C R Holanda,Nicoly F Gomes,Héliton Pandorfi,Marco A C Holanda

doi:10.1590/1807-1929/agriambi.v24n9p616-621

Janice M C Barnabé, José L S Carvalho Filho + Show 4 more

Open Access

https://doi.org/10.1590/1807-1929/agriambi.v24n9p616-621

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Abstract

ABSTRACT The objective of this research was to evaluate the thermal comfort, physiological responses and performance of pigs in the growth phase, subjected to supplemental lighting programs in air-conditioned environments, in semiarid region of Pernambuco state, Brazil. Twenty-seven pigs (3/4 Duroc, ¼ Pietrain) were subjected to pens with no climate control, pens with forced ventilation and pens with adiabatic evaporative cooling, associated with 12 h of natural light, 12 h of natural light + 4 h of artificial light and 12 h of natural light + 6 h of artificial light. The experimental design was completely randomized, in a 3 x 3 factorial arrangement with three repetitions. Meteorological responses, physiological responses and performance variables of the animals were recorded. The evaporative cooling system attenuated the action of the stressors and ensured adequate thermal conditions for the animals. Respiratory rate and rectal temperature indicated that evaporative cooling ensured the maintenance of homeothermy. Weight gain and feed conversion were positively influenced for the animals exposed to evaporative cooling, but without significant effect of lighting programs.

Highlights

Pigs are homeothermic animals, but have a limitation in the thermoregulation system, so the thermal environment is an extremely relevant factor in pig farming
Respiratory rate and rectal temperature indicated that evaporative cooling ensured the maintenance of homeothermy
Except for animals subjected to evaporative cooling, the animals were exposed to temperatures above the upper critical limit (UCL) of 27 °C (Santos et al, 2018), between 9 and 18 h, reaching extreme values (32.6 °C) at 14 h (Figure 1A)

Summary

Introduction

But have a limitation in the thermoregulation system, so the thermal environment is an extremely relevant factor in pig farming In this context, in Brazil, one of the concerns of producers is the high air temperature, associated with high relative humidity, which compromises the transfer of energy through latent heat and the low capacity of natural air renewal in the facilities, typical of a country with essentially tropical climate (Santos et al, 2012). Some management practices to counterbalance the effects of daily thermal stress suffered by animals go beyond the adjustment of the microclimate inside the production facilities, comprising the use of supplemental lighting (Amaral et al, 2014) This is a usual practice in poultry rearing systems, with satisfactory results, and its principle is to stimulate food intake at times of mild temperature (night time), when the micrometeorological conditions inside the housing environment facilitate the dissipation of energy from food, reducing the harmful effects of thermal and caloric stresses (Ferreira et al, 2015).

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