Clinical and subclinical milk fever are very costly. They incur not only direct economic losses, but also open the “door” to other illnesses. Health and fertility problems increase and longevity decreases. Especially the number of cases of subclinical (invisible) milk fever is strongly underestimated. Statistics from the field indicate that more than 70% of cows contend with it. Nutrition experts are looking for solutions to prevent calcium shortages around calving by modifying the ration during the dry period and adding anionic salts.