Livestock animals are homeothermic (chickens, sheep, goats, pigs, cattle) and are able to maintain a constant body temperature, regulating their production of heat by their metabolism and the losses with the surrounding environment. The body temperature varies for each species: chickens (41.0 °C), sheep (38.5 °C), goats (39.0 °C), pigs (38.0 °C) and cattle (38.0 °C). As environmental temperature changes, the animals adjust their physiology and behaviour in an attempt to keep their body temperature constant (DeShazer et al. 2009). Sensible heat losses occur by convection, conduction and radiation, and latent heat losses occur by respiration and from the skin surface (sweat rate and insensible perspiration). The mechanisms involved in heat gain and losses between animals and the environment are summarised in the figure.