Fatty liver disease occurs when there is an accumulation of fat in the liver. At the beginning of the dry period, the energy requirement of the cows decreases because they no longer produce milk. When the cows are still receiving an energy-rich ration, this ensures that fat is stored as belly fat at the organs. This fat is easily absorbed into the blood. When there is too much fat in the blood, the liver cannot handle it and becomes fat. In addition to the start of the dry period, the phase around calving is crucial. Cows enter a negative energy balance around calving. This is caused by the growth of the calf, the start of lactation and changes in the hormone balance.