Cattle production strategies to deliver protein with less land and lower environmental impact.

Global land resources are over-exploited and natural habitats are declining, often driven by expanding livestock production. In Ireland, pastureland for grazing cattle and sheep account for circa 60% of terrestrial land use. The agriculture, forestry and other land use sector (AFOLU) is responsible for 44% of national greenhouse gas (GHG) emissions. A new Grassland Animal response Model (GLAM) was developed to relate livestock-cohort grass and feed requirements to farm-grassland system areas, enhancing environmental assessment of prospective AFOLU configurations. Although land conversion targets are often well-defined, they tend to lack a clear definition of where land sparing can occur. Through analyses of 10 scenarios of milk and beef production and management strategies, we found that displacing beef cows with dairy cows can increase national protein output while sparing up to 0.75 million ha (18%) of grassland (albeit with a minor increase in overseas land requirement for additional concentrate feed). Reducing slaughter age, increasing exports of male dairy calves and increasing grassland use efficiency on beef farms each achieved between 0.19 and 0.32 million ha of land sparing. Sexed semen to achieve more favourable male-female birth ratios had a minor impact. GHG emissions, ammonia emissions and nutrient leaching were only reduced substantially when overall cattle numbers declined, confirming the need for cattle reductions to achieve environmental objectives. Nonetheless, application of GLAM shows potential for improved grass and cattle management to spare good quality land suitable for productive forestry and wetland restoration. This change is urgently needed to generate scalable carbon dioxide removals from the land sector in Ireland, and globally.

Evidence for scale-dependent root-antation feedback and its role in halting the spread of a pantropical shrub into an endemic sedge.

Vegetation pattern formation is a widespread phenomenon in resource-limited environments, but the driving mechanisms are largely unconfirmed empirically. Combining results of field studies and mathematical modeling, empirical evidence for a generic pattern-formation mechanism is demonstrated with the clonal shrub Guilandina bonduc L. (hereafter Guilandina) on the Brazilian island of Trindade. The mechanism is associated with water conduction by laterally spread roots and root augmentation as the shoot grows-a crucial element in the positive feedback loop that drives spatial patterning. Assuming precipitation-dependent root-shoot relations, the model accounts for the major vegetation landscapes on Trindade Island, substantiating lateral root augmentation as the driving mechanism of Guilandina patterning. Guilandina expands into surrounding communities dominated by the Trindade endemic, Cyperus atlanticus Hemsl. (hereafter Cyperus). It appears to do so by decreasing the water potential in soils below Cyperus through its dense lateral roots, leaving behind a patchy Guilandina-only landscape. We use this system to highlight a novel form of invasion, likely to apply to many other systems where the invasive species is pattern-forming. Depending on the level of water stress, the invasion can take two distinct forms: (i) a complete invasion at low stress that culminates in a patchy Guilandina-only landscape through a spot-replication process, and (ii) an incomplete invasion at high stress that begins but does not spread, forming isolated Guilandina spots of fixed size, surrounded by bare-soil halos, in an otherwise uniform Cyperus grassland. Thus, drier climates may act selectively on pattern-forming invasive species, imposing incomplete invasion and reducing the negative effects on native species.

Feeding Strategies to Mitigate Enteric Methane Emission from Ruminants in Grassland Systems.

Ruminants produce approximately 30% of total anthropogenic methane emissions globally. The objective of this manuscript was to review nutritional enteric methane abatement practices for ruminants that are applicable under grazing conditions. A total of 1548 peer-reviewed research articles related to the abatement of enteric methane emissions were retrieved and classified into four categories: non-experimental, in vitro, in vivo confined, and in vivo grazing. The methane abatement strategies for grazing systems were arranged into grazing management and supplementation practices. Only 9% of the retrieved papers have been conducted under grazing conditions. Eight grazing management practices have been evaluated to reduce methane emissions. Decreasing the pre-grazing herbage mass reduced the methane emission per unit of product. Other grazing management practices such as increased stocking rate, decreased forage maturity, rotational stocking, and incorporating tannin-containing or non-tannin-containing feeds showed contradictory results. Nitrogen fertilization or silvopastoral systems did not modify methane emissions. Conversely, supplementation practices in grazing conditions showed contradictory responses on methane emissions. Lipid supplementation showed promising results and suggests applicability under grazing conditions. Identifying and implementing grazing strategies and supplementation practices under grazing conditions is required to increase efficiency and reduce the environmental impact of these systems.

Physical and economic performance of dairy cows managed within contrasting grassland-based milk production systems over 3 successive lactations.

A diverse range of grassland-based milk production systems are practiced on dairy farms in temperate regions, with systems differing in relation to the proportion of grazed grass, conserved forages and concentrates in diet, calving season, duration of housing, cow genotype, and performance levels. The current study was conducted to examine performance within diverse grassland-based systems of milk production under experimental conditions. This study examined 4 milk production systems over 3 successive lactations (20 cows per system during each lactation). With winter calving-fully housed (WC-FH), Holstein cows were housed for the entire lactation and offered a complete diet consisting of grass silage, maize silage, and concentrates [approximately 50% forage on a dry matter (DM) basis]. With winter calving-conventional (WC-Con), Holstein cows were housed and offered the same diet from calving until turnout (late March) as offered with WC-FH, and thereafter cows were given access to grazing and supplemented with 5.0 kg of concentrate/cow daily. Two spring-calving systems were examined, the former involving Holstein cows (SC-H) and the latter Jersey × Holstein crossbred cows (SC-J×H). Cows on these systems were offered a grass silage-concentrate mix (70% forage on a DM basis) until turnout (late February), and thereafter cows were given access to grazing supplemented with 1.0 kg of concentrate/cow per day. The contributions of concentrates (3,080, 2,175, 722, and 760 kg of DM/cow per lactation), conserved forages (3,199, 1,556, 1,053, and 1,066 kg of DM/cow per lactation), and grazed grass (0, 2,041, 2,788, and 2,692 kg of DM/cow per lactation) to total DMI (6,362, 5,763, 4,563, and 4,473 kg of DM/cow per lactation) with WC-FH, WC-Con, SC-H, and SC-J×H, respectively, varied considerably. Similarly, milk yield (9,333, 8,443, 6,464, and 6,049 kg/cow per lactation), milk fat content (44.9, 43.3, 42.8, and 49.0 g/kg), and milk protein content (34.6, 34.9, 33.6, and 36.3 g/kg) differed between systems (WC-FH, WC-Con, SC-H, and SC-J×H, respectively). The higher milk yields with the WC systems reflect the greater concentrate inputs with these systems, whereas the greater milk fat and protein content with SC-J×H reflect the use of Jersey crossbred cows. Crossbred cows on SC-J×H produced a similar yield of milk solids as Holstein cows on SC-H. Cows on WC-FH ended the lactation with a greater body weight (BW) and body condition score than cows on any other treatment. While Jersey crossbred cows on SC-J×H had a lower BW than Holstein cows on SC-H, cows on these 2 systems were not different for any of the other BW, body condition score, or blood metabolite parameters examined. Cows on WC-FH had a greater interval from calving to conception, a greater mastitis incidence, and a greater locomotion score than cows on the spring calving systems. Whole-system stocking rates and annual milk outputs were calculated as 2.99, 2.62, 2.48, and 2.50 cows/ha, and 25,706, 20,822, 15,289, and 14,564 kg of milk/ha, with each of WC-FH, WC-Con, SC-H, and SC-J×H, respectively. Gross margin per cow was highest with WC-Con, gross margin per hectare was highest with WC-FH, and gross margin per kilogram of milk was highest with SC-J×H. This study demonstrated that diverse grassland-based milk production systems are associated with very different levels of performance when examined per cow and per hectare.

Methane production from four forages at three maturity stages in a ruminal in vitro system / Producción de metano de cuatro forrajes en tres estados de madurez en un sistema ruminal in vitro / Produção de metano de quatro forragens em três estágios de maturidade em um sistema ruminal in vitro

Abstract Background: Forage characteristics can modify in vitro methane production. There is little information about in vitro methane production of legumes and grasses at different maturity stages in tropical highland grazing systems. Objective: To evaluate the effect of species and forage maturity on in vitro methane production. Methods: Four forage species grown in tropical highlands of Colombia, two grasses: Kikuyu (Cenchrus clandestinus, previously named Pennisetum clandestinum) and ryegrass (Lolium perenne var. Samsum), and two legumes: Lotus (Lotus uliginosus var. Maku) and red clover (Trifolium pratense) were harvested in two paddocks at three maturity stages (young, intermediate, and mature). In vitro 48 h gas production was measured and methane proportion in gas was quantified by gas chromatography. Data were analysed as a randomized complete block (paddocks) design with a factorial arrangement 4×3 (4 species × 3 maturity stages) using the GLM procedure of SAS®. Results: Lotus produced less methane (p<0.01) than ryegrass, clover, and kikuyu (35.5 vs 64.7, 55.7 or 51.4 mL/g degraded organic matter, respectively). Younger forages produced less methane than intermediate and mature forages (42.8 vs 56.3 and 56.4 mL/g degraded organic matter, respectively). Cellulose concentration and organic matter degradability explained 67% (p<0.01) of methane production. Conclusion: Forage composition, presence of condensed tannins, and changes in fermentation patterns may explain the differences observed in in vitro methane production among species and maturity stages.

Resumen Antecedentes: Las características de los forrajes pueden afectar la producción de metano. Hay poca información sobre la producción de metano de leguminosas y gramíneas en diferentes estados de madurez en los sistemas pastoriles de trópico alto. Objetivo: Evaluar el efecto de la especie y la madurez de los forrajes sobre la producción de metano in vitro. Métodos: Cuatro especies forrajeras de trópico alto colombiano, dos gramíneas: Kikuyo (Cenchrus clandestinus, anteriormente llamado Pennisetum clandestinum) y ryegrass (Lolium perenne var. Samsum) y dos leguminosas: Lotus (Lotus uliginosus var. Maku) y trébol rojo (Trifolium pratense), fueron cosechadas de dos parcelas en tres estados de madurez (joven, intermedio y maduro). Se midió la producción de gas in vitro a las 48 h y la proporción de metano en el gas por cromatografía de gases. Los datos se analizaron empleando un diseño de bloques completos al azar (parcelas) con un arreglo factorial 4×3 (4 especies × 3 estados de madurez) mediante el procedimiento GLM de SAS®. Resultados: El lotus produjo menos metano (p<0,01) que el ryegrass, trébol o kikuyo (35,5 vs 64,7, 55,7 o 51,4 mL/g materia orgánica degradada, respectivamente). Los forrajes jóvenes produjeron menos metano que aquellos de edad intermedia y madura (42,8 vs 56,3 y 56,4 mL/g materia orgánica degradada, respectivamente). La concentración de celulosa y la digestibilidad de la materia orgánica explicaron el 67% (p<0,01) de la producción de metano. Conclusión: La composición de la pastura, la concentración de taninos condensados y los cambios en los patrones de fermentación pueden explicar las diferencias en la producción de metano in vitro según la especie y madurez del forraje.

Resumo Antecedentes: As caraterísticas das forragens podem modificar a produção de metano. Existe pouca informação sobre a produção de metano de leguminosas e gramíneas em diferentes fases de maturidade nos sistemas de pastoreio de trópico alto. Objetivo: Avaliar o efeito da espécie e a maturidade das forragens sobre a produção de metano in vitro. Métodos: Quatro espécies de forragens de trópico alto colombiano, duas gramíneas: Capim quicuio (Cenchrus clandestinus), antigamente chamado Pennisetum clandestinum) e azevém (Lolium perenne var. Samsum) e duas leguminosas: Trevina (Lotus uliginosus var. Maku) y trevo (Trifolium pratense), foram colhidas de duas parcelas diferentes em três fases diferentes de maturidade (jovem, intermedia e madura). Foi avaliada a produção de gás in vitro às 48 h e a proporção de metano foi determinada por cromatografia de gases. Os dados foram analisados com um delineamento em blocos ao acaso (parcelas) com um arranjo fatorial 4×3 (4 espécies × 3 fases de maturidade) utilizando o procedimento GLM de SAS®. Resultados: Trevina produz menos metano (p<0,01) que azevém, trevo o capim quicuio (35,5 vs 64,7, 55,7 ou 51,4 mL/g matéria orgânica degradada, respetivamente). Forragens jovens produzem menos metano que forragens com idade intermedia e matura (42,8 vs 56,3 y 56,4 mL/g matéria orgânica degradada, respetivamente). A concentração de celulosa e a digestibilidade da matéria orgânica explicaram o 67% (p<0,01) da produção de metano. Conclusão: A composição da pastagem, a concentração de taninos condensados e as mudanças nos padrões de fermentação podem explicar as diferencias na produção de metano in vitro entre espécies e maturidade de forragens.

Grassland futures in Great Britain - Productivity assessment and scenarios for land use change opportunities.

To optimise trade-offs provided by future changes in grassland use intensity, spatially and temporally explicit estimates of respective grassland productivities are required at the systems level. Here, we benchmark the potential national availability of grassland biomass, identify optimal strategies for its management, and investigate the relative importance of intensification over reversion (prioritising productivity versus environmental ecosystem services). Process-conservative meta-models for different grasslands were used to calculate the baseline dry matter yields (DMY; 1961-1990) at 1km2 resolution for the whole UK. The effects of climate change, rising atmospheric [CO2] and technological progress on baseline DMYs were used to estimate future grassland productivities (up to 2050) for low and medium CO2 emission scenarios of UKCP09. UK benchmark productivities of 12.5, 8.7 and 2.8t/ha on temporary, permanent and rough-grazing grassland, respectively, accounted for productivity gains by 2010. By 2050, productivities under medium emission scenario are predicted to increase to 15.5 and 9.8t/ha on temporary and permanent grassland, respectively, but not on rough grassland. Based on surveyed grassland distributions for Great Britain in 2010 the annual availability of grassland biomass is likely to rise from 64 to 72milliontonnes by 2050. Assuming optimal N application could close existing productivity gaps of ca. 40% a range of management options could deliver additional 21∗106tonnes of biomass available for bioenergy. Scenarios of changes in grassland use intensity demonstrated considerable scope for maintaining or further increasing grassland production and sparing some grassland for the provision of environmental ecosystem services.