Hot summer temperatures are a highly limiting factor for milk production of dairy cows. To maintain body temperature, cows reduce intake, which decreases the heat increment that results from rumen fermentation.
During the last 3 weeks of gestation, cow’s requirements for energy increase due to fetal development and colostrum production. At the same time, dry matter (DM) intake drops significantly during this period. This mismatch between nutrient intake and demand generates a negative energy balance towards the end of the pregnancy that is prolonged for several weeks after calving.