Adapted to heat stress
Heat stress occurs when temperature and humidity reach a certain level beyond which a cow’s body is unable to efficiently dissipate heat to maintain its normal body temperature. The heat stress indicator considers both parameters and refers to the Temperature-Humidity Index (THI). When the THI exceeds 68, animals are under heat stress (Herbut et al.; CNIEL, 2021). To cool down, animals adjust by increasing their respiratory rate and perspiration, which leads to electrolyte loss, such as sodium (Na) for instance. Animals can also modify their behavior by reducing their feed intake, rumen activity and thus their performance.
