Uso de N-alcanos para estimar o consumo e a digestibilidade da pastagem de coastcross-1 consorciada com "Arachis pintoi"

The trial was carried out to evaluate the alkanes (C27 to C35) profile, dry matter intake and digestibility of Coastcross-1 and Arachis pintoi mixed pasture with or without nitrogen fertilization in two periods (December/2003 and April/2004). The treatments evaluated were: CA0 = Coastcross + Arachis pintoi without N; CA100 = Coastcross + Arachis pintoi with 100 kg of N; CA200 = Coastcross + Arachis pintoi with 200 kg of N and C200 = Coastcross with 200 kg of N. The experimental period was composed by 8 days, with 3 days for marker administration (C32 in cellulose pelets) and 5 days for fecal collection, directly from animal rectum. Sixteen animals were used and maintained on grazed area since June 2003. From December to April, for pasture constituents, there was predominance of n-alkanes with odd chain, mainly for those with higher length chain (C29, C31 and C33), excepting leaves blade of Coastcross that presented the C27 alkane in higher concentration than C33. The highest amounts of n-alkanes C31 and C33 occurred during December. Animal’s intake and DMD did not present differences (P>0.05). The values of DMD using n-alkanes were similar to in vitro DMD of leaves blade from Coastcross.