Fig. 2

Incidence of pre-weaning diarrhea (PWD) in the four different sampling groups on the case farm. Each sampling group (1–4) had different number of litters (group 1 = 10, group 2 = 16, group 3 = 14, and group 4 = 10) and birth dates of the kits as seen in Table 1. The scoring of PWD was done every other day. However, due to the different birth dates of the mink kits the scoring of PWD ended at different ages of the kits (day 15 for group 1–3 and day 13 for group 4)