Mirelle Magalhães Souza

The aim of this study was to evaluate the effects of oregano essential oil (OEO) as a replacement for monensin (MON) on performance, carcass characteristics and meat quality in heifers finished either in confinement or on pasture. Thirty-six Nellore heifers (252.44 kg ± 21.80 kg) were distributed in a completely randomised design in a 2 × 2 factorial scheme, with two types of additives and two finishing systems. In both systems, a concentrate at 1.5% of body weight (BW) on a dry matter (DM) basis containing MON (282.2 mg/animal/day) or OEO (300 mg/animal/day) was offered daily. The final BW (FBW) and average daily gain (ADG) were higher in confinement-finished animals than in those finished on pasture (p < 0.01). There was no effect from the finishing system (p ≥ 0.376) or additive (p ≥ 0.057) for hot-carcass weight, hot-carcass yield, subcutaneous fat thickness, or the Longissimus lumborum area. The pH and shear force of the meat did not differ between treatments (p ≥ 0.076). Finishing in confinement resulted in brighter meat than finishing on pasture (p ≤ 0.006). The use of OEO increased the redness of the meat (p ≤ 0.042). Consumer perception (n = 63) of the sensory attributes of aroma, colour, tenderness, flavour and juiciness was not affected by the treatments (p > 0.05). Heifers finished in confinement or on pasture, with the same proportion of concentrate in the diet and the addition of MON or OEO, presented similar characteristics for both the carcass and the meat.

Silvopastoral systems (SPS) offer a sustainable alternative for animal production in tropical ecosystems. This study aimed to evaluate the effects of deferment days on herbage accumulation, plant-part composition, and canopy structural characteristics of Marandu palisadegrass (Urochloa brizantha Hochst. ex A. Rich.) in SPS with Eucalyptus urophylla and monoculture (MC). The experiment was conducted using a randomized block design, with each system individually allocated at the center of each plot in a 3 x 4 factorial arrangement, consisting of three systems: monoculture, and silvopastoral systems with tree row spacings of 12 m and 18 m, and tree intra-row spacing of 2 m, across four regrowth periods (60, 90, 120, and 150 days), each with three replications. Increasing deferment days reduced the proportion of green components in the forage, affecting tiller population density (TPD), leaf dry mass (LDM), and leaf/stem ratio. Maximum LDM production occurred at approximately 88 days with 0.63 Mg ha-1, while peak green dry mass (GDM) was at 94 days, reaching 1.11 Mg ha-1. Both dead material dry mass (DMDM) and total dry mass (TDM) increased linearly with regrowth periods, although TDM comprised about 47% dead forage. A regrowth period of 94 days from March is feasible for Marandu palisadegrass in SPS with 12 m and 18 m between tree rows, demonstrating that this spacing does not hinder forage production.

Silvopastoral systems (SPS) offer a sustainable alternative for animal production in tropical ecosystems. This study aimed to evaluate the effects of deferment days on herbage accumulation, plant-part composition, and canopy structural characteristics of Marandu palisadegrass (Urochloa brizantha Hochst. ex A. Rich.) in SPS with Eucalyptus urophylla and monoculture (MC). The experiment was conducted using a randomized block design, with each system individually allocated at the center of each plot in a 3 x 4 factorial arrangement, consisting of three systems: monoculture, and silvopastoral systems with tree row spacings of 12 m and 18 m, and tree intra-row spacing of 2 m, across four regrowth periods (60, 90, 120, and 150 days), each with three replications. Increasing deferment days reduced the proportion of green components in the forage, affecting tiller population density (TPD), leaf dry mass (LDM), and leaf/stem ratio. Maximum LDM production occurred at approximately 88 days with 0.63 Mg ha-1, while peak green dry mass (GDM) was at 94 days, reaching 1.11 Mg ha-1. Both dead material dry mass (DMDM) and total dry mass (TDM) increased linearly with regrowth periods, although TDM comprised about 47% dead forage. A regrowth period of 94 days from March is feasible for Marandu palisadegrass in SPS with 12 m and 18 m between tree rows, demonstrating that this spacing does not hinder forage production.

This study aimed to evaluate the chemical and mineral characteristics of Marandu grass under stockpiling in monoculture (MC) and a silvopastoral system (SPS) with 12- (SPS12) and 18-m (SPS18) spacing between tree rows. The experimental design consisted of randomized blocks, in which each system was allocated individually. Each treatment was formed in the center of each plot in a 3 × 4 factorial arrangement consisting of three systems (MC and SPS12 and SPS18 between the tree rows) and four stockpiling periods (60, 90, 120, and 150 days), totaling 12 treatments with three replications. No interaction effect was observed between the factors (p>0.05) for crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), phosphorus (P), potassium (K), calcium (Ca), or magnesium (Mg). The CP content decreased with increasing stockpiling days but met the suggested requirement for ruminants up to 75 days. The NDF and ADF concentrations increased, while P and K contents decreased with increasing stockpiling days. Magnesium and Ca concentrations did not differ with stockpiling days. However, a difference was observed only for Mg relative to the evaluated systems, which was higher in MC and SPS12, differing from SPS18. The spacing adopted in the SPS of 12 and 18 m does not negatively influence the nutritional value of the forage plant. The 75-day stockpiling period from March favored the concentration of macronutrients and CP content in Marandu grass in both MC and SPS.

Resumo O objetivo deste trabalho foi avaliar as características bromatológicas e minerais do capim Marandu sob diferimento em monocultivo (MC) e em sistema silvipastoril (SSP) com 12 (SSP12) e 18 m (SSP18). O delineamento experimental foi em blocos ao acaso, onde cada sistema foi alocado individualmente. No centro de cada parcela formou-se cada tratamento em fatorial de 3 × 4, composto por três sistemas (MC e SSP12 e SSP18 entre as fileiras das árvores) e quatro períodos de diferimento (60, 90, 120 e 150 dias), perfazendo doze tratamentos com três repetições. Não houve efeito de interação entre os fatores (p>0,05) para proteína bruta (PB), fibra em detergente ácido (FDA), fibra em detergente neutro (FDN), fósforo (P), potássio (K), cálcio (Ca) e magnésio ( Mg). O teor de PB diminuiu com o incremento nos dias de diferimento, mas até os 75 dias atendeu a demanda sugerida para ruminantes. As concentrações de FDN e FDA aumentaram, enquanto os teores de P e K diminuíram com o incremento nos dias de diferimento. A concentração de Mg e Ca não diferiu com os dias de diferimento. No entanto, em relação aos sistemas avaliados houve diferença apenas para Mg, que foi maior em MC e SPS12, diferindo de SPS18. O espaçamento adotado no SSP de 12 e 18m não influencia negativamente o valor nutricional da planta forrageira. O período de diferimento de 75 dias a partir de março favoreceu a concentração de macronutrientes e o teor de PB no capim marandu tanto em MC quanto nos SSP.