In some EU regions it is becoming popular to feed milk to calves only once a day to reduce labour. This practice, however, may restrict behavioural and physiological needs of a calf. The Directive 2008/119/EC specifies that calves must be fed twice a day with an appropriate diet adapted to their age, weight and behavioural and physiological needs, to promote good health and welfare. In this Thematic factsheet, the biological needs of calves, legal requirements and focus areas for inspection are described.