Ruminant livestock are an important source of anthropogenic methane (CH₄). Decreasing the emissions of enteric CH₄ from ruminant production is strategic to limit the global temperature increase to 1.5°C by 2050. Research in the area of enteric CH₄ mitigation has grown exponentially in the last 2 decades, with various strategies for enteric CH₄ abatement being investigated: production intensification, dietary manipulation (including supplementation and processing of concentrates and lipids, and management of forage and pastures), rumen manipulation (supplementation of ionophores, 3-nitrooxypropanol, macroalgae, alternative electron acceptors, and phytochemicals), and selection of low-CH₄-producing animals. Other enteric CH₄ mitigation strategies are at earlier stages of research but rapidly developing. Herein, we discuss and analyze the current status of available enteric CH₄ mitigation strategies with an emphasis on opportunities and barriers to their implementation in confined and partial grazing production systems, and in extensive and fully grazing production systems. For each enteric CH₄ mitigation strategy, we discuss its effectiveness to decrease total CH₄ emissions and emissions on a per animal product basis, safety issues, impacts on the emissions of other greenhouse gases, as well as other economic, regulatory, and societal aspects that are key to implementation. Most research has been conducted with confined animals, and considerably more research is needed to develop, adapt, and evaluate antimethanogenic strategies for grazing systems. In general, few options are currently available for extensive production systems without feed supplementation. Continuous research and development are needed to develop enteric CH₄ mitigation strategies that are locally applicable. Information is needed to calculate carbon footprints of interventions on a regional basis to evaluate the impact of mitigation strategies on net greenhouse gas emissions. Economically affordable enteric CH₄ mitigation solutions are urgently needed. Successful implementation of safe and effective antimethanogenic strategies will also require delivery mechanisms and adequate technical support for producers, as well as consumer involvement and acceptance. The most appropriate metrics should be used in quantifying the overall climate outcomes associated with mitigation of enteric CH₄ emissions. A holistic approach is required, and buy-in is needed at all levels of the supply chain.

In Brazil, pastures of Brachiaria grasses are often attacked by the spittlebug Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae). Biological control of this pest insect is rarely used, in part because of a lack of diversity in commercialized pathogens effective against such pests. However, fungal infection of M. spectabilis has been noted in some tropical silvopastoral systems, which rarely have problems with pest insects. This study surveyed the fungi found in association with M. spectabilis in a silvopastoral system in Brazil and made a preliminary assessment of their virulence. Infected spittlebugs were collected in a silvopastoral system in Brazil, from which 5 types of fungi were isolated and identified by morphological analysis. Conidia of each wild fungus and a commercial strain of Metarhizum anisopliae (Metschn.) Sorokin (Clavicipitaceae) were diluted in a 1% NaCl solution at a concentration of 1×104 conidia per mL. In the laboratory, eggs and nymphs of M. spectabilis were placed in... Resumo Pastagens com Brachiaria spp. geralmente sofrem ataques severos pela cigarrinha Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae). O controle biológico desse inseto tem sido pouco utilizado, principalmente porque há poucos entomopatógenos comercialmente disponíveis. Entretanto, M. spectabilis infectada por fungos tem sido encontrada em alguns sistemas silvipastoris (SSP) tropicais, os quais raramente apresentam problemas com insetos-praga. Este estudo é uma prospecção de fungos encontrados em associação com M. spectabilis e uma análise preliminar de sua virulência. Cigarrinhas infectadas foram coletadas em um SSP no Brasil, das quais cinco tipos de fungos foram isolados e identificados por análises morfológica e molecular. Conídios de cada um dos fungos selvagens e de uma linhagem comercial de Metarhizum anisopliae (Metschn.) Sorokin (Clavicipitaceae) foram diluídos em solução de NaCl 1% a uma concentração de 104 conídios/mL. No laboratório, ovos e ninfas de M. spectabilis foram colocados em ...

The negative climate change effect on ruminant production is increasing the risk of food security. Therefore, the search for alternative forages able to provide high volume of biomass and nutritional qualities and also adapted to a poor soil and climate conditions are extremely necessary. In this context, the high tropical biodiversity is able to provide potential forages for ruminants as a pasture or even as a fodder bank. The promissory results of our work on the use of Tithonia diversifolia as feed for dairy and beef cattle in Brazil and Colombia are showing its potential to attend nutritional requirements for medium and high performance cows. In addition, these studies are in line with the guidelines advocated by Food Agriculture Organization (FAO) for the promotion of sustainable intensification of animal production in the tropical world.

Among the alternatives identified as capable of making livestock farming a more efficient activity and reducing its environmental impact, the use of feeds with high digestibility and the use of non-conventional fodder species can be highlighted. Tithonia diversifolia (Hemsl.) A. Gray (TD) has already gained attention as a feed for ruminants. Nonetheless, there has been little discussion about the impacts of this plant on the rumen dynamics that lead to better animal performance. The aim of this study was to assess how increasing levels of TD could affect ruminal microbial biomass synthesis, degradability, and in vitro gas production (IVGP) of diets. Four diets were evaluated: a control diet (TD0: 400 g kg⁻¹ soybean meal and maize grain, and 600 g kg⁻¹ Tifton 85 hay (Cynodon spp.)) and three increasing levels of TD (TD9: 90, TD27: 270, and TD45: 450 g kg⁻¹–dry matter basis) as a replacement for dietary roughage. A 96 h IVGP assay was carried out and five incubation times (2, 4, 10, 24, and 96 h) were used for degradability determination. Gas produced, methane (CH4), degradability of organic matter (IVDOM), short-chained fatty acid (SCFA) production, partitioning factor (PF), and microbial biomass (MB) were evaluated among treatments. There was no significant effect (p > 0.05) between TD inclusion and IVGP at most incubation times; only at 6 h of incubation did gas production increase linearly with TD inclusion (R² = 0.19; p < 0.05). TD inclusion had no effects on CH4. IVDOM increased linearly with TD inclusion at 6 and 10 h, with TD45 being more degradable than the control diet at 6 h only. There was a positive linear relationship (R² = 0.20; p < 0.05) between TD inclusion and PF. TD45 had significantly higher PF values than the control. MB also increased linearly (R² = 0.30; p < 0.05) with TD inclusion, and all diets with TD had significantly more MB than the control diet. The inclusion of TD at the levels used in this work was revealed to have a positive impact on microbial protein synthesis, which could be related to the higher microbial efficiency of increased substrate quality.

Forage intake, feeding behavior and bio-climatological indices of pasture grass, under the influence of trees, in a silvopastoral system

To gain insights into the forage morphological and anatomical characteristics in a silvopastoral system (SPS) with Bolsa de Pastor (Zeyheria tuberculosa) and palisadegrass ‘Marandu’ (Urochloa brizantha) monoculture (MONO). The SPS was established through natural regeneration of the tree species. Treatments were a SPS and MONO distributed in a completely randomized design with six replicates and repeated measures were the harvest periods. Response variables were morpho-physiological and anatomical characteristicss: green: dead material ratio, leaf blade: stem+sheath ratio, leaf area index, chlorophyll and carotenoid concentrations, proportions of non-lignified and achlorophyllous areas, lignified areas in stems, proportions of non-lignified and achlorophyllous areas, lignified and chlorophyllous areas in leaves, as well as cell length in longitudinal section of stem. Morpho-physiological patterns were altered (p < 0.05) under natural shading conditions due to higher photosynthetic efficiency in the SPS. There was no effect (p > 0.05) of the systems on anatomical patterns, proportions of non-lignified and achlorophyllous, lignified and chlorophyllous tissues, these proportions were influenced only by the periods of the year, both for stems and leaves. Cells of the internodes of the grasses of the studied systems had the same length. The SPS alters morpho-physiological characteristics of palisadegrass and increases the concentration of chlorophyll a and b.