Lignification of plant cell walls has been identified as a major factor limiting forage digestibility. It limits the amount of digestible energy available to livestock, resulting in an incomplete utilisation of cellulose and hemicellulose by ruminant animals. Modification of the lignin profile of ryegrasses (Lolium spp.) and fescues (Festuca spp.) is undertaken through modulating the expression of genes encoding enzymes involved in the biosynthesis of monolignols