Does a sheep's motivation to avoid hot conditions correspond to the physiological cost of remaining in those conditions?

Abstract

Two experiments investigated whether an animal's motivation to avoid hot conditions was aligned with its physiological response to the same conditions. In Experiment 1 (physiology), Merino ewes (n=12 per treatment) were assigned to 5 d of heat challenge: 20, 25, 30 or 35 °C with 70% humidity. In Experiment 2, 6 Merino ewes were trained to press a panel to open a door between the heat challenge pen and a cool pen at 20 °C. Each animal was exposed to the same temperatures as Experiment 1 and four fixed work ratios (1, 4,10 and 25 panel presses), with one temperature and fixed ratio per 9-h test session.