In 2 stages of a trial the bodyweight of 16 calves (6 Fleckvieh female, 6 Braunvieh female, 4 Braunvieh male), experimentally infected with Sarcoptes bovis, was controlled between birth and until 25 weeks after treatment with Ivomec pour-on (5 mg ivermectin/10 kg b.w.). On the day of treatment and before the turnout to the pasture the living Sarcoptes mites and mange lesions were determined. The two stages were characterized by different degrees of mange, which also became noticeable in the daily increase of bodyweight on an average of 200 g and 570 g respectively compared with the untreated calves. After treatment of the animals of the control group the daily increase in bodyweight within a few weeks was identical with the increase of the bodyweight of the earlier treated calves, whereby 16/19 weeks after the turnout to the pasture (female calves) and the possibility to take in grass ad libitum and 16 weeks after beginning of fattening (male calves) respectively the group of earlier treated calves still showed a higher mean bodyweight of about 27 kg and 24 kg.