Digestion kinetics of NDF in dairy cows fed silages from primary growth and regrowth of grass

Abstract

Two grass silages from primary growth (PG) and two from regrowth (RG) were investigated in a 4x4 Latin square experiment by rumen cannulated dairy cows. Digestion kinetics of NDF was determined by rumen evacuations and the omasal canal flow measurements. Dry matter intake of PG was higher, rumen content of indigestible NDF (INDF) lower and passage rate of INDF higher in PG than in RG. Rumen contents of NDF and INDF increased with progressing growth stage of grass within harvest. It is concluded that intake of early cut PG and both RG silages was not limited by rumen fill alone.