Two flocks of ewes with lambs were compared for differences in performance. One group was permanently infected with footrot, the other one served as healthy control. They were kept in the same barn but in different bays during lambing and on pasture during the summer. Biweekly all animals were weighed and in the affected group all feet were scored for severity of footrot and if necessary the claws were treated. Furthermore the body condition was scored 4 times in the ewes. The lambs were slaughtered with 43 kg. At that time age and carcass quality were used as parameters. In 20 lambs of each group the lying behaviour was measured using a datalogger during 5 consecutive days. The results revealed significant differences in the performance of ewes and lambs between the two groups. The overall duration of fattening was 31.8 days longer in affected animals. Most importantly, even mild footrot led to significantly impaired growth of the lambs and an altered lying behaviour compared to the healthy controls. The lying periods were more frequent but of shorter duration in affected lambs.