Produção animal em pastagens de Coastcross-1 consorciada com Arachis Pintoi com e sem adubação nitrogenada

• Ano de defesa: 2006
• Autor(a) principal: Paris, Wagner
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; Programa de Pós-Graduação em Zootecnia; UEM; Maringá, PR; Centro de Ciências Agrárias
• Palavras-chave em Português: Bovinos; Desempenho animal - Pastagem consorciada; Adubadação nitrogenada; Ciências Agrárias; Zootecnia
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/1601

This work consisted of four trials evaluating in a field experiment, the following treatments: 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, in a randomly block design, with two replicates during the years of 2003 and 2004. Pasture management was done through continuous grazing with variable stocking rate. Crossbred heifers (Bos indicus x Bos taurus) were used with three animals testers per treatment. Animal performance was evaluated in the first trial. For average daily gain (ADG) and gain per hectare (GPH) it was observed high gains to treatments CA200 and C200, over CA100 and CA0 with values of 0.51; 0.51; 0.42 and 0.38 kg/day, respectively. The (GPH) was higher than 1000 kg/ha/year. Average stocking rate was 4.5 AU/ha during all year, with 7.5 and 2.5 AU/ha on summer and winter, respectively. The accumulation rate was above 22.4 tons in the year, with no difference (P>0.05) among treatments. Arachis pintoi percentage on mixture was higher during spring and to CA0 treatment, with visual estimates always higher than the real due the lower dry matter (DM) of this legume, super estimating the population. On second trial it was evaluated the pasture structural constituents (leaf blade (LB), sheath + green stem (SGS), dead material (DE) and whole plant of Arachis pintoi (WPA)), in relation to production and quality. The structural constituents' production varied in agreement with the forage mass, and CA200 and C200 had the highest monthly values of LB and SGS. For DE it was not observed difference, however, WPA was higher on CA0. The values of 19.5 % and 20% of crude protein (CP), and 63.1% and 63.4% for dry matter in vitro digestibility (DMIVD) of LB from Coastcross and WPA, respectively, were similar, with one difference on neutral detergent fiber (NDF) of WPA (50%) in relation to LB from Coastcross (68.2%), confirming the high quality of these materials. To SGS the values for CP, NDF and DMIVD were 9%, 75% and 54%, respectively. On third trial it were evaluated the forage mass (FM), CP and NDF percentage on 0 to 7 cm, 7 to 14 and above 14 cm layers of LB, SGS, DE fractions and leaf/stem ratio of Coastcross grass and whole plant of Arachis pintoi. The proportion of LB and the leaf/stem ratio increased and SGS, DE and WPA decreased with clipping height increase, and were not observed difference among treatments. WPA had little influence on pasture composition, mainly on higher layer and on winter, when it was not present. The highest values for CP (P<0.05) and the lowest for NDF were observed on intermediary and higher layers of LB, SGS and WPA. The treatment with no fertilization presented the lowest CP value (P<0.05) than the others, in all layers and plant constituents, with a higher pasture quality in autumn and spring. The objectives of forth trial were to determine the alkane profile (C27 to C35), the animal's intake and pasture dry matter digestibility during December to April. It was observed predominance of n-alkanes with odd chain, mainly for those with higher chain length and the amount had alterations during year seasons, when there were higher C31 and C33 concentrations on December. The grazing animal's intake was influenced by forage offer, mainly on April, where the higher offer (P<0.05) caused a higher (P<0.05) intake per animal. The digestibility values using n-alkanes were similar to leaves blade DMIVD of Coastcross. The results presented that the use of n-alkane technique in tropical conditions makes possible the estimative of intake and digestibility in grazing conditions.