Diarrhoea (defined as abnormal frequency and fluidity of faecal evacuations) was recorded for each calf individually.
The RSP design consisted of three dose levels, in which all the calves were started on the same dose at the first design level, but thereafter participated in the study based only on own obtained results. The grades of negative reactions (milk detected in the rumen or failure to ingest the offered amount) determine the dose for the subsequent levels. All calves were given 4.0 l at the first RSP level, and the meal size was subsequently changed individually based on the obtained results, i.e. milk detected in the rumen or failure to ingest the amount offered. The minimum and maximum meal size were set to be 1.0 and 7.0 l, respectively.