In Switzerland, the entry of veal calves in the fattening unit at the age of 4-7 weeks coincides with the transition from passive to active immunity. The main objective of this study was to determine the effect of the entry age in the fattening unit on the health status of veal calves. Three groups of 30 calves ranging from 2 to 4, 5 to 7 and 8 to 10 weeks of age were simultaneously brought to the fattening unit. The age of entry influenced neither clinical symptoms or respiratory disorders incidence. The number, duration, and success rate of the antibiotic treatments were similar in the three groups. In conclusion, the arrival of veal calves in the fattening unit during the period of immune transition did not have any negative influence on their health status.