Resumo: O objetivo deste trabalho foi avaliar a qualidade da pastagem e a emissão de metano (CH4) entérico de bovinos Curraleiro Pé-duro x Nelore, em pastagem de Megathyrsus maximus 'Mombaça', tanto a pleno sol como em consórcio com palmeiras de babaçu (Attalea spp.), no bioma Amazônia. O delineamento experimental foi inteiramente casualizado, com seis novilhos por sistema, e as avaliações foram realizadas nos períodos seco (2015) e no chuvoso (2016). Em comparação à forragem no sistema a pleno sol, a forragem no sistema silvopastoril apresentou maiores teores de proteína bruta, extrato etéreo, nutrientes digestíveis totais e digestibilidade in vitro da matéria orgânica, e menores teores de matéria seca, fibra em detergente neutro e carboidratos totais (CHOT). No período das águas, o sistema silvopastoril apresentou maiores teores de proteína bruta e reduções de carboidratos não fibrosos e CHOT. As emissões de CH4 foram semelhantes entre os sistemas, tendo variado de 44,0 a 74,2 kg por animal por ano. No período seco, a emissão por quilograma de matéria seca ingerida e a perda de energia bruta por metano foram menores no sistema silvopastoril. No período chuvoso, as emissões foram similares entre os tratamentos. O sistema silvopastoril oferece pastagem de boa qualidade na seca e, considerando-se o ciclo com ambos os períodos, é mais eficiente (emissão de CH4 pelo ganho de peso diário) do que o sistema a pleno sol.

Abstract: The objective of this work was to evaluate the quality of pasture and enteric methane (CH4) emission of Curraleiro Pé-duro x Nellore cattle in a pasture of Megathyrsus maximus 'Mombaça', both in full sun and in a consortium with babassu palms (Attalea spp.) in the Amazonian biome. The experimental design was completely randomized, with six steers per system, and the evaluations were done during the dry period (2015) and rainy period (2016). In comparison to forage in the full sun system, forage in the silvopastoral system showed, in the dry period, higher levels of crude protein, ether extract, total digestible nutrient, and in vitro digestible organic matter, and lower levels of dry matter, neutral detergent fiber, and total carbohydrate (TCHO). In the rainy period, forage in the silvopastoral system showed higher levels of crude protein and a reduction of nonfibrous carbohydrate and TCHO. The CH4 emissions were similar in both systems within the same period, and ranged from 44.0 to 74.2 kg per year per animal. During the dry period, the emission per kilogram of dry ingested matter and the loss of gross energy as methane were lower in the silvopastoral system. During the rainy period, the emissions were similar in both systems. The silvopastoral system yields forage with good quality in the dry period, and considering both periods, it is more efficient (emission of CH4 per daily weight gain) than the system in full sun.

ABSTRACT The objective of this study was to evaluate live weight and carcass traits, from birth to slaughter, and meat quality of Nellore (NEL), Curraleiro Pé-Duro (CPD), and crossbred (F1) products in the state of Piauí, Brazil. Progenies from CPD, NEL, and their F1 crossbred (½ NEL + ½ CPD), a total of 252, males and females, from birth to 24 months of age, were evaluated in a comparative study in growth performance. The steers were sent to slaughter at 28 months of age and carcasses and meat quality were analyzed. After slaughter, carcass weight, dressing percentage and Longissimus dorsi area (rib eye area) were evaluated; an index was created by the relationship between these measures per hundred kg of chilled carcass produced. To assess meat quality, the shear force, water-holding capacity, color, brightness, pH, and cooking loss were investigated. Results obtained showed that month and year of birth were significant on growth, indicating influence of climatic variables. Nellore offspring was heavier than F1 and this was heavier than CPD throughout the study period, including the hot and cold carcass. No differences were found in dressing percentage among NEL and F1, but CPD and F1 showed a rib eye area and index significantly higher than NEL. The meat from CPD group presented a stronger red coloration than the others, but there was no significant difference in the remaining meat qualitative variables among the three groups. Curraleiro Pé-Duro and F1 crossbred produce more meat per 100 kg of carcass than Nellore in natural pasture of Piauí State.