ABSTRACT.- Efficient pasture-based animal production systems require optimisation of forage production with the highest nutritive value. Increasing the defoliation regimen of pastures allows to improve the nutritive value of forage for ruminants but it can be detrimental for total biomass production. An experiment was carried out to study the effect of the defoliation regimen around flowering time on productivity, chemical composition and nutritional value of tall fescue. The experiment was carried out on 4-year old orchardgrass (Dactylis glomerata cv 'INIA Perseo') pasture, at the experimental station "La Estanzuela" (INIA, Uruguay).