High-Roughage System for Raising Calves Based on the Early Development of Rumen Function. XII. In Vivo and In Vitro Changes in Rumen Contents of Calves Fed Alfalfa, Beet Pulp, or Soybran Flakes as the Roughage in Complete Pelleted Rations

Thirteen tIolstein and seven Jersey calves were used to study changes in rnmen contents to 16 wk of age when fed complete high-roughage (67%) pelleted rations in which the principal roughage was either alfalfa (OA), beet pulp (OB), or soybran flakes (OS). The pH and volatile fatty acid content of fresh strained rumen juice plus in vitro fatty acid production and cellulose digestibility in an artificial tureen were used as criteria in following the development of rumen function. The propionie acid separated chromatographically from fresh rumen juice was highest in the group fed soybran flakes (OS). Also, in vitro cellulose digestion was highest in the (OS) group.