1. Calves which had been reared for 12 weeks on three milk feeds and either cut grass or concentrates-with-hay, were introduced to an all-grass diet when weaned.

2. Eight animals were kept indoors and fed herbage cut from paddocks grazed by nineteen similar calves.

3. After an initial period of about 2 weeks there was a tendency for grass-reared calves to make slightly better live-weight gains.

4. No difference could be shown in the intake of herbage dry matter by these groups of calves.

5. There was little indication that grass-reared animals digested their food more efficiently. It appeared that they converted grass to animal tissue better, but further study is required to substantiate this.