The objective was to characterize the nutrient and mineral composition of M. maximus cv Aruana grazed by lambs in a silvopastoral system or full sun with added nitrogen. The treatments are: (1) Aruana grazed in full sun with nitrogen fertilization, (2) Aruana grazed in full sun without nitrogen fertilization, (3) Aruana grazed in a silvopastoral system with nitrogen fertilization and (4) Aruana grazed in a silvopastoral system without nitrogen fertilization. The nutrient dynamics, urinary excretion of N and the amount returned of the nutrient were determined from four sheep in a Latin square experimental design; the analysis of the mineral composition of the leaves and stalks of the grass was carried out by collecting samples from the plots used, totaling six in each treatment evaluated. The silvopastoral system provided high levels of P and K in forage plants. Urinary N excretion and urine mineral contents were influenced by the systems evaluated and the use of N fertilizer. N did not show differences for leaves and canes.

The objective of this work was to evaluate the quantitative and qualitative characteristics of carcass and meat of Dorper x Santa Ines crossbred lambs finished in a silvopastoral system, pasture or feedlot. Twenty-four non-castrated male lambs were used (8 animals in each production system). The experimental design was completely randomized, with three production systems and eight replications. The production systems were: pasture of Megathyrsus maximus cv. Aruana, without shading + feed supplementation (Pasture); pasture of Megathyrsus maximus cv. Aruana, with natural shading provided by the native laurel tree (Cordia trichotoma) + feed supplementation (Silvopastoral) and feedlot. The cold carcass weight, empty body weight, cold carcass yield, fat color, fat consistency and carcass compactness index showed significant differences (P < 0.05) between production systems, with higher values observed in the feedlot. The shoulder weight and the percentage of shoulder components (bones, muscle, fat and others), did not significantly differ (P > 0.05) between production systems. The pasture silvopastoral systems presented similar results and also, when contrasted with the feedlot system, did not influence the parameters related to meat. Feedlot provided better quantitative and qualitative characteristics to the lambs’ carcassess.

The objective of this work was to compare the zootechnical performance of Dorper x Santa Inês crossbred lambs finished in grazing systems on Megathyrsus maximus Aruana cultivar pasture, with and without shading, and in a feedlot. Twenty-four non-castrated lambs were used in a completely randomized experimental design, with the three following treatments with eight replicates each: 'Aruana' pasture without shading + supplement; 'Aruana' pasture with shading + supplement; and feedlot, with diet containing ryegrass hay and concentrate at a 20:80 ratio. The treatments did not influence lamb age at slaughter, birth weight, leg compactness, true yield, and main cut yield, except that of breast tip + flank that was lower for the pasture with shading. However, average daily gain, body condition score, live weight at slaughter, carcass compactness index, cold carcass and empty body weights, and cold carcass yield differed between treatments, showing higher values in the feedlot. Termination in the feedlot increases the zootechnical performance of Dorper x Santa Inês sheep and favors a lower age at slaughter, as well as a greater weight of the main commercial cuts, but not their yield.

The objective of this work was to evaluate the effects of the use of additives on the ensiling of AGRI 002E sorghum (Sorghum bicolor), focusing on the chemical composition, loss, microbial profile, and fermentative stability of the fodder. Sorghum was harvested 111 days after sowing, chopped, and ensiled in PVC silos under different treatments, as follows: without additives (SS), with inoculant (SSI), with urea (SSU), and with urea and inoculant (SSUI). The silos were opened and analyzed at 1, 3, 7, 14, 28, and 56 days after ensiling. The inclusion of urea and bacterial inoculant did not significantly affect dry matter content, but influenced dry matter recovery and microbial population, reducing the presence of clostridia and fungi. Dry matter and gas losses were minimal, indicating an adequate fermentation. The additives contribute to a more stable fermentation and a better preservation of the ensiled material, particularly by reducing undesirable microbial populations.

O objetivo do presente trabalho foi avaliar o efeito da adubação nitrogenada em M. maximus cv. Aruana cultivado em sistema silvipastoril e pleno sol sobre as características morfogênicas, estruturais, produtivas e composição química. Sistemas silvipastoris promovem eficiência produtiva e sustentabilidade na produção animal, melhorando a forragem e o conforto térmico. A adubação nitrogenada afeta o crescimento de forrageiras tropicais. O estudo avaliou o sistema utilizado (silvipastoril e pleno sol), adubação (com e sem) e períodos (21, 42, 63 e 84 dias) em características produtivas e morfogênicas da forrageira. O sistema silvipastoril elevou a altura do dossel, enquanto o pleno sol favoreceu a matéria seca e ganho de peso animal. A adubação beneficiou a densidade de perfilhos basais e morfogênese. O teor de proteína bruta foi maior no pleno sol. Pleno sol teve vantagens na forragem e composição, enquanto o silvipastoril destacou-se na altura do dossel. A adubação melhorou várias características, incentivando renovação tecidual. O estudo destaca a importância do manejo adequado em sistemas silvipastoris para otimizar produção e qualidade forrageira.