Thermal comfort indices assessed in integrated production systems in the Brazilian savannah

Abstract

The objective was to evaluate the animal thermal comfort indices from two integrated croplivestock- forestry (ICLF) systems. For this, temperature? humidity index (THI), black globe temperature and humidity index (BGHI), and the radiant thermal load (RTL) were assessed. Two ICLF (ICLF-1 and ICLF-2) systems and one control system were established. On the ICLF systems, the arboreal component was the eucalyptus tree (Eucalyptus grandis 9 Eucalyptus urophylla; H13 clone), planted in simple widespaced rows. The ICLF-1 system had a tree spacing of 14 9 2 m with 357 trees per hectare, and the ICLF-2 had a tree spacing of 22 9 2 m with 227 trees per hectare. The control system had five scattered native trees per hectare, pertaining to Gochnatia and Dipteryx species. The forage component in all three systems was piata?-grass (Brachiaria brizantha cv. BRS Piata?). The experimental design was a randomized block in a sub-subplot design scheme with four replications. The presence of shade provided by the trees offered better conditions of animal comfort when compared with the condition of full sun. The ICLF-1 system, with higher tree density, provided better indicators for thermal comfort, THI, BGHI, and RTL when compared with the condition of full sun, while ICLF-2 was no different than ICLF-1 for BGHI.