Abstract 1. 1.|This study presents an estimate of the energy budget of two Boran steers in a hot, radiative environment through a quantitative evaluation of each avenue of heat gain and loss, in near-nature field conditions. 2. 2.|The mean per cent error in the energy budget for the two steers was −9·3 and −15·1, with the estimate of heat loss larger than heat gain. Present techniques and methods are evaluated through an analysis of this error.