Search

Extensive cattle production on native grasslands is vital to the sustainability of the South American Pampas, and the inclusion of tannin-containing legumes can increase farm profitability, improve nitrogen (N) use and reduce greenhouse gas (GHG) emissions. This study quantified the effects of adding tannin-containing legumes to native grasslands on enteric methane (CH4) emissions, animal performance and N balance in cattle. A crossover design trial was conducted with 22 beef heifers under two treatments: native grassland (NG) and native grassland with the addition of Lotus uliginosus and L. angustissimus (NG+L). The results showed that forage mass disappearance was similar between treatments; however, 54% of the forage disappearance in the NG+L corresponded with legumes, indicating that the heifers in this treatment consumed a better-quality diet. While individual CH4 emissions were similar between treatments, heifers grazing the NG+L showed a higher average daily gain (ADG) and lower emissions intensity than heifers grazing NGs (0.25 vs. 0.58 g CH4/g ADG, p < 0.05). Additionally, they also ingested 20% more N and were more efficient in its utilization. Incorporating tannin-containing legumes into native grasslands can improve animal productivity and N use efficiency while reducing the intensity of enteric CH4 emissions. [ABSTRACT FROM AUTHOR]

While concerns about greenhouse gas (GHG) emissions and animal welfare persist, livestock farming offers unique ecosystem services. In Argentina, where livestock significantly contributes to GHG emissions, particularly enteric methane (CH4), urgent action is required to develop effective mitigation strategies while maintaining animal performance. This study assesses the potential of the inclusion of Lotus tenuis in natural grasslands to mitigate CH4 emissions and improve forage quality in the Salado River basin, Argentina. Twenty-four beef heifers (361 ± 19 kg LW) were assigned to two treatments with contrasting botanical composition (LOT: > 80% Lotus tenuis and NG: > 60% grasses). LOT showed better forage quality and reduced CH4 emissions (−17% gCH4/day, p < 0.01; Ym: - 7 to −30%, p < 0.05) compared to NG. However, the condensed tannin content in LOT was insufficient to conclusively attribute any impact on CH4 emissions. This study underscores the potential of promoted Lotus tenuis pastures in the Salado River basin to enhance forage quality and mitigate enteric CH4 emissions in free-ranging cattle systems, albeit additional research is necessary to fully comprehend how this practice interacts within the ecosystem and optimise its benefits. [ABSTRACT FROM AUTHOR]

The SF6 gas tracer technique is extensively used to measure enteric CH4 emissions for scientific research in Latin-American countries. Although guidelines on how to properly implement this technique have been published, its use has been the subject of considerable uncertainty due to a high variation within measurements when compared to results obtained with other techniques. Therefore, a detailed evaluation of this technique is important to identify the main sources of variability. The aim of this study is to summarise the key factors contributing to this variation, as reported in studies conducted in Latin America (LA). The final dataset comprised 63 studies and the variables considered within our analysis were split into two main categories: (1) Production systems and animal-related factors driving enteric CH4 emissions and (2) Aspects related to the implementation of the SF6 gas tracer technique in research laboratories, such as: duration of the collection period, and mean permeation rate of the SF6 collection canisters, among others. The lack of specific details regarding the SF6 gas tracer technique in the compiled dataset from LA studies is notable. Despite this, the main sources of variation identified were related to both the duration of the sampling period and the SF6 permeation rate. [ABSTRACT FROM AUTHOR]