Each year, around 250 000, predominantly male, calves are fattened on Swiss farms. Despite different amelioration measures on the fattening farms, the rate of morbidity, mortality and antibiotic use remains high. In a transdisciplinary research project, the rearing conditions on the dairy farms will be improved. The awareness and strategies of milk producers, fatteners, veterinarians and other stakeholders will be investigated with a mixed methods study. On the basis of current veterinary research results, a strategy for dealing with calves on the farm of birth ("ImproCalf") will be developed, which is based on (a) scientifically supported reduction of risk factors, (b) including solutions of the stakeholders, and (c) is deemed viable. In an on-farm study, calves will be raised on birth farms and randomly distributed to two groups to be (a) reared the standard way or (b) reared using the ImproCalf-Strategy, until transfer to the fattening farm. The groups will be compared based on performance, morbidity, mortality and the administration of medication.