Timothy and bromegrass were studied in pure sowings in a glasshouse, and each in a mixture with lucerne, dominated by the grass–fraction in the first crop year, in the field. In the glasshouse both species were cut 3, 5, or 6 times at a 2–in. and 6 times at a 3/4–in. stubble height. In timothy, cutting 6 times gave lower DM but higher protein yields than less frequent cutting. In bromegrass close cutting gave higher DM yields than lax cutting. The following results applied to both species: root weight decreased with increasing severity of defoliation, final tiller density was very low under close cutting, and a complete application of N at the time of sowing was superior to a split application.In the field, the first cut was taken on 5 dates at intervals of 1 week, the second cut 6 or 8 weeks after the first cut, and the third cut 7 weeks after the second cut (for bromegrass mixture only). DM yield was generally the higher the later the first cut was taken and the longer the subsequent rest period. However, the opposite applied for best sustainment of yield. The 1 1/2–in. stubble treatments outyielded the 3 1/2–in. treatments. Generally, production of CP was influenced more by DM yield than by % content. Reduced removal of tiller primordia in the second cut led to higher third–cut yields, but at the cost of total yield. Difficulties in the control of shoot apex removal encountered in both glasshouse and field ar