Heat stress can cause reduced rumen function and lower feed intake, which leads to a reduced energy supply and impacts dairy performance. Milk yield and milk components are reduced. Milk loss is linked to both heat stress levels and duration of exposure. Lallemand Animal Nutrition developed a more precise categorization of losses thanks to several scientific publications that represent different situations all around the world. For dairy cows, the common threshold used by the scientific community was 68 (Burgos and Collier. 2013). However, practical field studies show that heat stress can impact dairy cattle starting at a temperature-humidity index (THI) of 62. Hammani (et al., 2013), studied heat stress in northern Europe and defined that heat stress can impact cows at 62. Bourraoui (et al., 2002) found higher losses in milk, fat and protein yields in Mediterranean regions.<\/p>\n","protected":false},"excerpt":{"rendered":"