Herbage Allowance, Production and Composition of a Lolium Perenne Pasture

Abstract

For a better understanding of the consequences of the application of different grazing intensities, functions of response of composition and forage production of a pasture of Lolium perenne under different grazing herbage allowance levels (OF) were developed, and their structural characteristics were analysed with a multivariate method. The OF evaluated were 2.0- 4.5-7.0 and 9.5 DM kg/100 kg of animal liveweight/day. The relationships between forage production and relative forage utilization with the OF were lineal: forage production (DM kg/ha)=3619+1078OF, (P<0.0038; r² =0.74); forage utilization (percentage )=88.8- 3.86OF, (P <0.0066; r² =0.69), but no differences were detected in the disappeared forage. The relationship between pre-graze aerial biomass and foliage height (cm) for the entire period was: aerial biomass (DM kg/ha) = -758 + 237x (P <0.0001; r² = 0.79), for x=height (cm). The pre-graze green leaves biomass was lineally affected (P <0.01; r² =0.70) by the remainder green leaves biomass post-graze and by tillers density (P <0.0001; r² =0.67). Principal component analysis indicated that, under these conditions, only the biggest OF evaluated maintained the values of variables relatively high, suggesting a highest pasture productivity and stability under these treatments. The relationships achieved are useful for pasture management, although the environmental conditions changed during the experimental period, the grazing frequency was higher than the recommended and some tillers began to reproductive state.