Tithonia diversifolia (Hemsl.) A. Gray has significant potential as a forage source in silvopastoral systems, particularly in tropical conditions. However, its intensity and frequency management differ from those commonly applied to grasses. This study aims to evaluate T. diversifolia under two harvest intensities (30 and 40 cm stubble height) and four harvest frequencies (21, 28, 35 and 42 days), aligning with Brazil's traditional tropical grass management practices. Biomass production and nutritive value of forage, as well as in vitro rumen fermentation parameters, were assessed. We observed that the tested harvest intensities have a limited impact on the biomass production and nutritional value of T. diversifolia. Despite the linear increase in biomass production, lower harvest frequencies (i.e., longer regrowth period) significantly affect nutritional value, impacting the products of ruminal fermentation, as indicated by the in vitro assay. The methane production per gram of degraded organic matter (OM) and the OM allocated for microbial biomass production are affected by the harvest frequencies. Additionally, we observed that rainfall and canopy height have a stronger correlation with biomass production than harvest frequencies controlled by days. We conclude that T. diversifolia is minimally affected by harvest intensities and, for Brazilian edaphoclimatic conditions, it can be harvested with higher frequencies than those suggested for other regions.

ABSTRACT Tree density is an important aspect in silvopastoral system (SPS) planning, since low luminosity can limit forage perenniality, especially for tropical forages of C4 metabolism. The objective with this study was to verify if an SPS with high tree density accelerates the pasture degradation process and changes the forage chemical composition. The experiment was carried out by comparison of marandu palisade grass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster] pasture in two systems: silvopastoral and open pasture. In the SPS, teak (Tectona grandis) was planted with a density of 750 trees ha-1. Evaluations were carried out over three years (2015, 2016 and 2017). SPS shading reduced herbage mass, tiller density and soil cover over the years. In the marandu palisade grass in the SPS there was a greater stem proportion, which favoured lesser potential digestible dry matter in the first year. Even with a higher amount of stem, higher crude protein concentration and minerals were observed in the SPS. Due to the high density of trees, excessive shading accelerated the process of degradation of the pasture, which demonstrates that planning of the spatial arrangement of tree species is crucial.

Context Forage–livestock systems contribute to Brazilian greenhouse gas (GHG) emissions, harming the environment and reducing bioeconomic efficiency. Employing technologies like pasture management is crucial for sustainable mitigation. Aims Our objective was to measure greenhouse gas emissions of beef cattle in forage systems by exploring well-managed Brachiaria hybrid pastures in the Brazilian Amazon Biome. Methods The experimental design was a randomised complete block, with two cultivars: Ipyporã and Mulato II, in four replicates, totalling eight experimental units, and each experimental unit was 1.5 ha. Key results Ipyporã pastures had 88.5% greater herbage mass than Mulato II in January (8350 vs 4430 kg dry mass ha−1). There was no difference between cultivars for soil GHG emissions. The greatest enteric methane and carbon dioxide values were measured in February. In Ipyporã pastures, the average daily gain was 57% and 50% greater than in Mulato II, in February (837 vs 533 g day−1) and March (1054 vs 700 g day−1) respectively. Enteric methane and carbon dioxide were 34% and 48% less respectively in Ipyporã pastures in February. Conclusions Soil GHG emissions in fertilised pastures followed similar patterns across different cultivars, but those with greater production tended to produce more emissions (soil and enteric) due to fertilisation and increased stocking rates. Implications Forage–livestock production systems benefit from adequate grazing and pasture management of two Brachiaria cultivars, resulting in greater productivity compared to GHG emissions. This leads to reduced emissions per unit of product, contributing to the development of a more efficient and sustainable forage–livestock system.

Ensuring the sustainability and circularity of mixed crop-ruminant livestock systems is essential if they are to deliver on the enhancement of long-term productivity and profitability with a smaller footprint. The objectives of this study were to select indicators in the environmental, economic and social dimensions of sustainability of crop-livestock systems, to assess if these indicators are relevant in the operational schedule of farmers, and to score the indicators in these farm systems. The scoring system was based on relevance to farmers, data availability, frequency of use, and policy. The study was successful in the assemblage of a suite of indicators comprising three dimensions of sustainability and the development of criteria to assess the usefulness of these indicators in crop-ruminant livestock systems in distinct agro-climatic regions across the globe. Except for ammonia emissions, indicators within the Emissions to air theme obtained high scores, as expected from mixed crop-ruminant systems in countries transitioning towards low emission production systems. Despite the inherent association between nutrient losses and water quality, the sum of scores was numerically greater for the former, attributed to a mix of economic and policy incentives. The sum of indicator scores within the Profitability theme (farm net income, expenditure and revenue) received the highest scores in the economic dimension. The Workforce theme (diversity, education, succession) stood out within the social dimension, reflecting the need for an engaged labor force that requires knowledge and skills in both crop and livestock husbandry. The development of surveys with farmers/stakeholders to assess the relevance of farm-scale indicators and tools is important to support direct actions and policies in support of sustainable mixed crop-ruminant livestock farm systems.

Understanding how forage can be utilized in the rumen is important for optimizing system efficiency. We aimed to evaluate the ruminal fermentation parameters and methane (CH4) production of Marandu palisadegrass [Brachiaria (syn. Urochloa) brizantha (Hochst. ex A. Rich.) R. D. Webster] growing in monoculture or in integrated systems. The experiment was conducted over 3 years to evaluate four systems [livestock (L), livestock-forestry (LF), crop-livestock (CL), and crop-livestock-forestry (CLF)] during the dry and rainy seasons. In the dry season, palisadegrass in CLF presented the greater crude protein (CP) and the lesser neutral detergent fibre (NDF) concentrations. The greatest gas volume was produced in L, while LF and CL reduced CH4 production compared to L. The greatest ammoniacal-nitrogen concentration, propionate and valeric acid proportions, and degradability of NDF were in CLF. In the rainy season, palisadegrass in LF and CLF presented the greater CP concentration and the lesser CH4 production. Integration of crop and forestry components in a forage-based livestock system affected ruminal fermentation parameters of Marandu palisadegrass, consequently, reducing CH4 production. In addition, the inclusion of a forestry component enhanced forage CP concentration. Integrated systems can improve ruminal fermentation, supporting sustainable livestock production and optimizing forage utilization.

Intensification of livestock systems becomes essential to meet the food demand of the growing world population, but it is important to consider the environmental impact of these systems. To assess the potential of forage-based livestock systems to offset greenhouse gas (GHG) emissions, the net carbon (C) balance of four systems in the Brazilian Amazon Biome was estimated: livestock (L) with a monoculture of Marandu palisade grass [Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster]; livestock-forestry (LF) with palisade grass intercropped with three rows of eucalyptus at 128 trees/ha; crop-livestock (CL) with soybeans and then corn + palisade grass, rotated with livestock every two years; and crop-livestock-forestry (CLF) with CL + one row of eucalyptus at 72 trees/ha. Over the four years studied, the systems with crops (CL and CLF) produced more human-edible protein than those without them (L and LF) (3010 vs. 755 kg/ha). Methane contributed the most to total GHG emissions: a mean of 85 % for L and LF and 67 % for CL and CLF. Consequently, L and LF had greater total GHG emissions (mean of 30 Mg CO2eq/ha/year). Over the four years, the system with the most negative net C balance (i.e., C storage) was LF when expressed per ha (-53.3 Mg CO2eq/ha), CLF when expressed per kg of carcass (-26 kg CO2eq/kg carcass), and LF when expressed per kg of human-edible protein (-72 kg CO2eq/kg human-edible protein). Even the L system can store C if well managed, leading to benefits such as increased meat as well as improved soil quality. Moreover, including crops and forestry in these livestock systems enhances these benefits, emphasizing the potential of integrated systems to offset GHG emissions.

Two experiments were carried out to evaluate the effect of monensin in supplements for grazing heifers. In experiment I, treatments consisted of protein supplements (low intake – 0.5 kg/animal/day and high intake – 1.0 kg/animal/day) associated or not with monensin. Animal performance, nutrient intake, and digestibility were evaluated. Forty crossbred heifers with an initial body weight (BW) of 213.8 ± 4.5 kg were used. There was no difference in average daily gain between treatments (average of 0.588 kg/animal/day). There was no interaction between monensin and supplements for intake parameters and digestibility. Dry matter (DM) intake was equal between treatments ( 2

This study evaluated the effect of increased energy via supplementation on the performance, ingestive behavior, nutrient digestibility, and nitrogen metabolism of grazing heifers fed tropical forage in the rainy-dry transition season. Treatments consisted of mineral supplementation ad libitum (control) and multiple supplements formulated to provide different energy levels and the same amount of protein (300 g CP animal d-1) and were denominated as low (LE; 340 g TDN animal d-1), medium (ME; 780 g TDN animal d-1) and high (HE; 1220 g TDN animal d-1) energy. Animals supplemented with ME, and HE had a greater average daily gain in relation to the control treatment, with an increase of 41 and 46%, respectively. Greater values for total apparent digestibility of neutral detergent fiber were observed for the treatment HE. Lesser values of urinary urea N were observed for the control and HE treatments. Our results define the use of energy levels in the supplement as a tool for pasture management. If the purpose of the production system is to enhance forage intake, the option is to supply supplements with less energy levels. In contrast, if the purpose is to increase the stocking rate, supplements with greater energy levels should be used.

Forage is a low-cost food for cattle production. To achieve maximum economic and productive efficiency, nitrogen dose must be adjusted as well as the ideal time to carry out the application. Thereby, this work aimed to identify the appropriate moment to realize nitrogen maintenance fertilization on cultivars of Panicum maximum (syn. Megathyrsus maximus): BRS Tamani e MG 12 Paredão. Two experiments were carried out in a greenhouse. The first experiment (Experiment 1) at Federal University of Mato Grosso, Cuiabá, and the second experiment (Experiment 2) at Federal University of Rondonópolis. Treatments consisted of five intervals between forage defoliation and nitrogen fertilization: 0, 2, 4, 6, and 8 days. Harvests were done when Tamani and MG 12 Paredão guinea grass reached 30 + 0.70 and 78 + 0.70 cm, respectively. The intervals between forage defoliation and nitrogen fertilization did not influence the development of MG 12 Paredão, except for tiller number. In contrast, the intervals between forage defoliation and nitrogen fertilization of BRS Tamani changed the leaf number, tiller number, dry mass of each leaf blade, dry mass of each tiller, leaf blade dry mass, stem dry mass and shoot dry mass. The longer the interval between defoliation and nitrogen fertilization on BRS Tamani, the greater the decrease in development, which impacted negatively on forage mass. There was no common biological response for both cultivars, even belonging to the same species, therefore, MG 12 Paredão has flexibility for fertilization timing, while BRS Tamani fertilization should be performed as close as possible to defoliation.

A criação de bovinos no Brasil ocorre, prioritariamente, em pastagens e, neste contexto, a adubação do pasto é uma importante estratégia de aumento na eficiência produtiva. Diante disso, objetivou-se, com esta revisão, descrever os impactos técnicos da adubação no desenvolvimento de gramíneas tropicais. A calagem é uma prática importante na disponibilidade dos nutrientes e, novos estudos visam demonstrar que o intervalo entre a incorporação do calcário e a semeadura tem maior dependência da umidade do solo e que é possível reduzir este período que tradicionalmente é de 60 a 90 dias. A adubação fosfatada tem maior impacto sobre a implantação do que a manutenção do pasto, e quando negligenciada na formação do pasto, observa-se um efeito residual sobre a rebrota. O nitrogênio e o potássio são os nutrientes mais extraídos na manutenção dos pastos, o que se torna importante o estudo da relação entre estes nutrientes, bem como a adoção da adubação potássica em sistemas em que a adubação nitrogenada é uma prática rotineira. A varredura, que consiste na mistura de sobras de fertilizantes em galpões, embora tenha baixo custo por quilo de produto, o uso pode ser antieconômico, o que depende da composição do insumo adquirido. Palavras-chave: calagem; fertilização de pastos; formação de pastagens. Technical and economic impacts of pasture fertilization ABSTRACT: Cattle production on Brazil priority occurs in grasslands, in this context, pasture fertilization is an important strategy to improve production efficiency. Therefore, the aim with this review is to describe the technical impacts of fertilization on tropical grass development. Liming is an important practice in nutrient availability and new studies aim to demonstrate that the interval between limestone incorporation and seeding has more dependence on soil moisture, and that is possible to reduce this period, which traditionally is from 60 to 90 days. Phosphate fertilization has a greater impact on pasture implantation than maintenance, and when neglected in pasture formation, there is a residual effect on regrowth. Nitrogen and potassium are the nutrients extracted on pasture maintenance, which makes it important to study the relationship between these nutrients, as well as the adoption of potassium fertilization in systems where nitrogen fertilization is a routine practice. Mixing leftover fertilizers in warehouses, although it has a low cost per kilo of product, the use can be uneconomical, which depends on the input composition purchased. Keywords: liming; pasture fertilization; pasture implantation.

Timing of nitrogen (N) fertilizer application can influence grass regrowth, so it is important to identify how tropical grasses respond to delays in applying fertilizer after defoliation. Our objective was to identify the effects of timing of N fertilizer application after harvest on the productive, morphogenic and structural characteristics of 3 tropical grasses: ‘Xaraés’ (Urochloa brizantha [Hochst. ex A. Rich.] Stapf cv. Xaraés), ‘Marandu’ (Urochloa brizantha [Hochst. ex A. Rich.] Stapf cv. Marandu) and ‘Tanzânia’ (Megathyrsus maximus [Jacq.] cv. Tanzânia). The experiments were performed in a greenhouse, in a completely randomized design, with 5 delays in applying N after harvesting (0, 3, 6, 9 and 12 days). Delaying fertilizer application did not affect the forage mass of Xaraés and Marandu palisade grass (7.4 and 7.8 g/pot, respectively). There was a linear decrease in number of leaves per tiller and leaf appearance rate, but tiller population density and phyllochron increased linearly as fertilizer application was delayed. Grass forage mass (12.2‒10.6 g/pot), number of leaves per tiller (3.1‒2.6 leaves/tiller) and forage accumulation rate (0.47 to 0.41 g DM/d) of Tanzânia guinea decreased linearly as N application was delayed, but tiller population density was unaffected (25 tillers/pot). Based on our results, N fertilizer should be applied to Tanzânia guinea grass pastures as soon as possible after harvest and certainly before 3 days, while there is not the same urgency with Xaraés and Marandu where fertilization could be delayed up to 12 days without significant detriment. These suggestions need to be tested in a field study before being recommended widely.

Cattle production on Brazil priority occurs in grasslands, in this context, pasture fertilization is an important strategy to improve production efficiency. Therefore, the aim with this review is to describe the technical impacts of fertilization on tropical grass development. Liming is an important practice in nutrient availability and new studies aim to demonstrate that the interval between limestone incorporation and seeding has more dependence on soil moisture, and that is possible to reduce this period, which traditionally is from 60 to 90 days. Phosphate fertilization has a greater impact on pasture implantation than maintenance, and when neglected in pasture formation, there is a residual effect on regrowth. Nitrogen and potassium are the nutrients extracted on pasture maintenance, which makes it important to study the relationship between these nutrients, as well as the adoption of potassium fertilization in systems where nitrogen fertilization is a routine practice. Mixing leftover fertilizers in warehouses, although it has a low cost per kilo of product, the use can be uneconomical, which depends on the input composition purchased.

The addition of protein supplementation in a silvopastoral system can contribute to improved forage intake and digestibility. Our objective was to evaluate in vitro ruminal parameters, digestibility and gas production of Marandu palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster] in a silvopastoral system and compare this to parameters obtained from diets with protein supplementation. Forage was sampled during the growing season (November to April) in 2016/17 and 2017/18. In vitro incubation treatments consisted of four levels of protein supplement (20% of crude protein; CP) in the diet (0.1, 0.2, 0.3 and 0.4 g/kg of body weight). The neutral detergent fibre, acid detergent fibre and indigestible neutral detergent fibre concentrations were highest in the first year. In the second year, CP concentration was 21% greater than in the first year. There was a linear increase for digestion rate, a quadratic effect for lag time and a linear decrease for average digestion time as supplementation levels were increased. The least lag time and digestion time occurred in the second year. There was no supplementation effect on ruminal pH, acetate and butyrate concentrations. Second-year in vitro dry matter digestibility (IVDMD) was greater than in the first year. Increases in supplementation levels linearly enhanced IVDMD and reduced methane (CH4) production. The inclusion of a protein supplement contributed to reduced CH4 and increased volatile fatty acids production; therefore, we recommended the supplement inclusion of >0.28 g/kg of BW for animals grazing in well-managed palisadegrass pastures.

The absence of nutrient replacement, especially nitrogen (N), is one of the main causes of grazing system underutilization and tropical climate pasture degradation. Therefore, N is a very important nutrient in the pasture maintenance; however, it is necessary to know the maximum limit to be used of this nutrient, since fertilization increases production cost. Thus, the objective of this study was to identify the N dose that provides the highest production of marandu palisadegrass (Brachiaria brizantha cv. Marandu), and the fertilization effect on pasture degradation process and forage nutritive value. Treatments consisted in the application of : 0 (control), 25, 50, 75 and 100 kg N ha(-1) cycle(-1) of regrowth. The evaluations were carried out during the summers (November to April) of 2015/2016 and 2016/2017. The highest dry matter yield (DMY) and forage accumulation rate (FAR) occurred between doses of 50 and 75 kg ha(-1) cycle(-1), with no change in productive potential at higher doses. The reduction in mineral content and the increase in crude protein (CP) are the main changes in the nutritional value of marandu palisadegrass, with no pronounced effect on in vitro dry matter digestibility (IVDMD), indigestible neutral detergent fiber (iNDF) and potentially digestible dry matter proportions of CP in the cell wall (CPCW) and in cellular content (CPCC).The productive effect of nitrogen fertilization under marandu palisadegrass is the increase in DMY and FAR. Thus, the use of nitrogen fertilizers in pasture systems with marandu palisadegrass has a greater impact on the area gain than the individual gain, assuming these systems, the use of nitrogen doses of 50 to 75 kg ha(-1) cycle(-1).

In dairy production systems, the use of strategies to increase production can be used, however some care must be taken to avoid the loss of nitrogen in the system, which is directly related to the environmental impacts. The aim with this study was to evaluate and the effect of the use of CP levels in concentrate in intensive systems on the productive performance and nitrogen metabolism of dairy cows in a tropical forage-based system. Sixteen multiparous Holstein-Zebu crossbreed cows in the middle and final third of lactation were used in a replicated 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments design with 2 grazing systems (traditional and intensive) and 2 CP levels (18 and 22% CP) in concentrate. In intensive system, fertilization and irrigation were performed, while in traditional system, there was no fertilization and irrigation. Grazing systems affected all milk yield and composition variables, except for milk protein and solids. Greater milk yield was observed for cows in intensive system. Milk solids content was greater for cows supplemented with 18% CP level. Milk fat, protein, lactose, and solids yield was greater for cows in intensive system. Nitrogen use efficiency was greater for cows in traditional system. Milk N excreted was similar between supplemented cows, however, it was greater for cows in intensive system compared to cows in traditional system as well as 22% CP level. There was a grazing systems effect for ruminal ammonia nitrogen concentration with lesser values for cows in traditional system. The 22% CP level increased ruminal ammonia nitrogen. The results obtained in this study showed that cows in pastures under intensive system showed protein and energy imbalance in the rumen. The increase in CP levels does not affect the productive characteristics of these animals, only resulting in higher costs and higher N excretion to the environment.

Alterações no ambiente luminoso provocam mudanças adaptativas nas plantas, na tentativa de manter o seu crescimento e desenvolvimento. Objetivou-se com esta revisão investigar e descrever o efeito do ambiente luminoso no crescimento e desenvolvimento de forrageiras de clima tropical em sistemas silvipastoris. A compreensão da influência do ambiente luminoso e, das mudanças biológicas que as diferentes intensidades do sombreamento podem causar nas forrageiras de clima tropical, possibilita fundamentar as alterações metabólicas das respostas das plantas na tentativa de se manterem persistentes em sistemas sombreados. A partir disso, entender quais são os níveis aceitáveis de radiação para que os sistemas de produção sombreados não entrem em colapso é fundamental para que tomadas de decisões sejam realizadas no tempo hábil do ciclo biológico das espécies vegetais. Em sistemas silvipastoris, a redução da luz incidente em forrageiras de clima tropical provoca alterações como aumento da área foliar específica, redução na densidade populacional de perfilhos e na relação raízes: parte aérea da planta. Cada espécie ou cultivar apresenta características adaptativas específicas ao sombreamento com a finalidade de aproveitar os recursos disponíveis em tecidos fotossintéticos e de suporte. No entanto, ainda assim o sombreamento intenso (>40%) afeta negativamente a produção forrageira de acordo com a variabilidade climática. Palavras-chave: adaptação morfofisiológica; fotossíntese; luz; plantas C4. EFFECT OF THE LIGHT ENVIRONMENT IN TROPICAL CLIMATE FORAGES IN SILVOPASTORAL SYSTEMS ABSTRACT: Changes in the light environment cause adaptive changes in plants, to maintain their growth and development. The aim of this review is to investigate and describe the light environment effect on the growth and development of tropical forages in silvopastoral systems. The understanding of the influence of the light environment and the biological changes that different shading intensities can cause in tropical forages, makes it possible to substantiate the metabolic alterations of plant responses to remain persistent in shaded systems. From this, understanding what are the acceptable levels of radiation so that the systems do not collapse is essential for decision-making to be carried out in a timely manner in the plant's biological cycle. In silvopastoral systems, a light incidence reduction on tropical forages causes changes such as an increase in the leaf area index, reduction in the tiller population density, and shoot: root ratio. Each species or cultivar has adaptive characteristics specific to shading to take advantage of the resources available in photosynthetic and support tissue. However, even so, the intense shading (> 40%) negatively affects forage production according to climatic variability. Keywords: morphophysiological adaptation; photosynthesis; light; C4 plants.

Reactive natural phosphate is a slow and gradual solubilizing fertilizer, which makes it difficult to use in neutral to alkaline soils. Nitrogen fertilizers which acidify the soil may increase the possibility of using this phosphate fertilizer commercially. Two greenhouse experiments were conducted to compare responses of Xaraés palisadegrass (Urochloa brizantha syn. Brachiaria brizantha cv. Xaraés) and Mombasa guineagrass (Megathyrsus maximus syn. Panicum maximum cv. Mombasa), when different combinations of P and N fertilizers were applied during the establishment phase in non-acidic soils or with corrected acidity. The experiments were carried out in a completely randomized design with 3 fertilizer combinations (simple superphosphate plus urea, SSU; natural reactive phosphate plus urea, RPU; and natural reactive phosphate plus ammonium sulfate, RPAS). There was no difference in tiller density, leaf numbers, forage mass, leaf mass and stem mass for either forage on SSU and RPAS treatments but they exceeded those on RPU. Soil pH was lower in soil fertilized with ammonium sulfate than in soil fertilized with urea. Applying natural reactive phosphate plus ammonium sulfate seems as effective as simple superphosphate plus urea in promoting increased growth in tropical grasses on low-P soils. Longer-term and more extensive field studies are needed to determine if these results can be reproduced in the long term, and the level of soil acidification over time.

Ipypora grass, a Brachiaria interspecific hybrid was developed by crossing a genotype of Brachiaria ruziziensis (syn. Urochloa ruziziensis) and an access of Brachiaria brizantha (syn. Urochloa brizantha), which have different nitrogen requirements. Therefore, the objective with work was to verify the nitrogen requirement of the interspecific hybrid of Brachiaria hybrid cv. Ipypora. Experiment was carried out in a greenhouse in a randomized block design, with twelve treatments and four replications. Treatments consisted of a 4 x 3 factorial arrangement, with four nitrogen doses (0; 100; 200 and 300 mg/dm(3)) and three forages (Brachiaria hybrid cv. BRS Ipypora, Brachiaria humidicola cv. Llanero and Panicum maximum cv. Zuri). Each experimental plot consisted of a 3 dm(3) pot with three plants. Three evaluation harvest were done. B. hybrid had greater response to nitrogen fertilization for number of tillers and leaves than the other forages. However, for the total dry mass, B. hybrid was less responsive to nitrogen than P. maximum grass (high demand) and more responsive than B. humidicola (low demand), which shows that this hybrid has medium nitrogen requirement.

This study evaluated the effect of energy and protein supplementation on the nutritional characteristics, ingestive behavior, and productive performance in grazing heifers during the rainy season. Forty crossbred heifers (Nelore breed predominance) were used in the study, with an age of 14 months and an initial mean weight of 182 ± 1.13 kg. The treatments consisted of mineral supplementation ad libitum (control) and three supplements formulated to contain an energy: protein ratio (TDN:CP) of 1.13, 2.62, and 4.06; these were denominated as low (LC, 0.5 kg animal d−1), medium (MC, 1.0 kg animal d−1), and high consumption (HC, 1.5 kg animal d−1), respectively, in order to guarantee an intake of 300 g of crude protein (CP) animal−1 d −1, with variation in energy content. There was a difference (P < 0.05) in crude protein intake, with a 44% reduction for the LC treatment in relation to HC. The lowest grazing time (398 min) was observed with the MC treatment. Urinary urea-N (UreaN) was lower for control animals (P < 0.05). Average daily gain (ADG) was lower for the control animals than for the supplemented animals (P < 0.05); there was no difference in ADG between the animals receiving supplementation. High supplementation levels and TDN:CP ratios are not recommended because they do not justify the increased costs of supplementation. Therefore, when forage presents great nutritional characteristics, it is possible to optimize the performance of the animals with low to medium consumption supplementation.

The aim of this study was to evaluate the effects of Brachiaria seed contact time with 05-25-15 fertilizer (N-P2O5-K2O) on the seed’s physiological quality. The experimental design was a completely randomized design with four replicates. Treatments were arranged in a 5x4 factorial, being: five seeds contact times with fertilizer (0, 24, 48, 72 and 96 hours); four forages: Marandu palisadegrass, Piatã palisadegrass, Xaraés palisadegrass and Ruziziensis grass. The performed tests were: water content, germination (first count and germination percentage), tetrazolium (viability), electrical conductivity, accelerated aging, sand emergency and emergence speed index. Contact time of 05-25-15 fertilizer with Brachiaria seeds reduces linearly: Germination, emergence and emergence speed index of Brachiaria seeds; Piatã and Xaraés palisadegrass seeds viability; vigor (electrical conductivity), except in Ruziziensis grass seeds; and seeds germination of Piatã palisadegrass submitted to accelerated aging test (vigor). Piatã palisadegrass is the least recommended, among the analyzed grasses, for intercropping in simultaneous sowing.