Productivity changes in a rye grass praire grazed with beef cattle

Abstract

This experiment was made in order to obtain information about dry matter production in an artificial rye grass (Lolium multiflorum Lam) paire under cattle grazing. Traits were the combining of two factors, A = animals allowed tirne on pasture (1, 2, 4 and 8 hours) and B grazing dates and cutting (four periods, montly spaced). Previous to each grazing allowance measures on plants height, density and covering were taken. The paire was tilled with the variety Tam-90, seeding 35 kg ha1, in a land of 6.5 ha, fertilizing at once 80:50:00 N:P:K units. Grazing started 60 days after tillage, using a herd of 58 beef calf (172 kg started average). The dependent variables were: total forage yield on green and dry matter basis (TGM and TDM); remainder forage, also on green and dry matter basis (RFG and RFD); plant height, density and covering. The statistical analysis led to know real differences (P<.05) among B levels; the TGM mean by cuts was 16.73 t ha1 and 2.72 t ha1 for TDM; the multirange mean test (DMS,.05) indicated the fourth date as the lower. Significant differences (P<.01) about residual forage were found for the two factors, underlaying that higher values were for the first two times and first two dates. Variables taken previous grazing were different (P<.01) only for factor B leveles, pointed that the better characteristics were for the two earlier dates.