Search Results (197)

Dietary tannin supplementation represents a potential strategy to modulate rumen fermentation and enhance lactation performance in dairy cows, though responses remain inconsistent. A 21-day feeding trial was conducted to evaluate the effect of chestnut tannin (CNT) extract on the enteric methane emissions (EME), blood metabolites, and milk production traits in mid-lactation dairy cows. Thirty-six Holstein cows were allocated to three homogeneous treatment groups: control (CNT₀, 0 g/d CNT), CNT₄₀ (40 g/d CNT), and CNT₈₀ (80 g/d CNT). Measurements of EME, dry matter intake (DMI), milk yield (MY), and blood and milk parameters were carried out pre- and post-21-day supplementation period. Compared with the no-additive group, the CNT extract reduced methane production, methane yield, and methane intensity in CNT₄₀ and CNT₈₀ (p < 0.001). CNT₄₀ and CNT₈₀ cows exhibited lower blood urea nitrogen (p = 0.019 and p = 0.002) and elevated serum insulin (p = 0.003 and p < 0.001) and growth hormone concentrations (p = 0.046 and p = 0.034), coinciding with reduced aspartate aminotransferase (p = 0.016 and p = 0.045), and lactate dehydrogenase (p = 0.011 and p = 0.008) activities compared to control. However, CNT₈₀ had higher circulating NEFA and BHBA than CNT₀ (p = 0.003 and p = 0.004) and CNT₄₀ (p = 0.035 and p = 0.019). The blood glucose, albumin, and total bilirubin concentrations were not affected. MY and fat- and protein-corrected milk (FPCM), MY/DMI, and FPCM/DMI were higher in both CNT₄₀ (p = 0.004, p = 0.003, p = 0.014, p = 0.010) and CNT₈₀ (p = 0.002, p = 0.003, p = 0.008, p = 0.013) cows compared with controls. Feeding CNT₈₀ resulted in higher protein content (p = 0.015) but lower fat percentage in milk (p = 0.004) compared to CNT₀. Milk urea nitrogen and somatic cell counts were significantly lower in both CNT₄₀ (p < 0.001, p = 0.009) and CNT₈₀ (p < 0.001 for both) compared to CNT₀, while milk lactose did not differ between treatments. These findings demonstrate that chestnut tannin extract effectively mitigates EME while enhancing lactation performance in mid-lactation dairy cows. Full article

Measuring methane (CH₄) emissions from dairy systems is crucial for advancing sustainable agricultural practices aimed at mitigating climate change. However, current CH₄ measurement techniques are primarily designed for controlled research settings and are not readily scalable to diverse production environments. Thus, there is a need to develop accessible, production-level methods for estimating CH₄ emissions. This review examines the relationship between enteric CH₄ emissions and milk fatty acid (FA) composition, highlights key FA groups with potential as biomarkers for indirect CH₄ estimation, and outlines critical factors of predictive model development. Several milk FAs exhibit strong and consistent correlations to CH₄ emissions, supporting their utility as predictive biomarkers. Saturated and branched-chain FAs are generally positively associated with CH₄ emissions, while unsaturated FAs, including linolenic acid, conjugated linoleic acids, and odd-chain FAs, are typically negatively associated. Variability in the strength and direction of correlations across studies is often attributable to differences in diet or lactation stage. Similarly, differences in experimental design, data processing, and model development contribute to much of the variation observed in predictive equations across studies. Future research should aim to (1) identify milk FAs that consistently correlate with CH₄ emissions regardless of diet, (2) develop robust and standardized prediction models, and (3) prioritize the external validation of prediction models across herds and production systems. Full article

The present study aimed to evaluate the effects of dietary supplementation with organic oregano (Origanum vulgare) essential oil (OEO) on the rumen microbial population, with a focus on methanogenic archaea, in lactating dairy goats. A total of nine age-matched goats (mean body weight 49 ± 1.8 kg) were assigned to three experimental groups (n = 3 per group) in a completely randomized design. All animals were fed a basal diet consisting of a corn-based concentrate and a forage mix composed of alfalfa hay, wheat straw and corn silage. Group 1 was the control group while Groups 2 and 3 received an OEO supplement at dosages of 1 mL/day and 2 mL/day per animal, respectively, incorporated into the concentrate feed. Rumen fluid samples were collected on days 15, 30 and 45 of the feeding trial and their microbial profile was assessed using NGS analysis. The results demonstrated a reduction in the relative abundance of methanobacteria in both OEO-supplemented groups compared to the control group. Statistical analysis revealed significant differences between feeding groups and days of sampling. These findings suggest that OEO has the potential to modulate the rumen microbiome by reducing methane-producing archaeal populations. In conclusion, dietary supplementation with OEO may serve as a natural strategy to mitigate enteric methane emissions in Alpine dairy goats. Full article

Pasture-based dairy systems are a cornerstone of agricultural practices in the Azores, contributing significantly to both the local economy and environmental sustainability. However, the environmental impact of these systems, particularly in terms of methane (CH₄) emissions, remains a major challenge, especially given the need to balance productivity with ecological preservation. This study aimed to compare enteric methane emissions, floristic composition, productivity, and nutritional quality between conventional and organic pasture systems in the Azores. Data were collected from representative dairy farms over a 12-month period, with pasture samples analyzed monthly to assess floristic diversity, dry matter productivity, and nutritional quality (crude protein and digestibility). Methane emissions were estimated using the IPCC Tier 2 methodology, incorporating data on animal performance, diet composition, and energy intake to calculate CH₄ emissions per cow per year. The results showed that organic pastures had greater floristic diversity (5.10 ± 0.25 species/m²) than conventional pastures (4.00 ± 0.23 species/m²). However, conventional systems exhibited higher dry matter productivity (22.85 g/m² vs. 15.35 g/m²) and incorporated corn silage, which enhanced digestible energy and reduced methane emissions (81.33 kg CH₄/cow/year) compared to organic systems (89.17 kg CH₄/cow/year). Although organic pastures had higher crude protein content (20.65%), their lower digestibility contributed to higher methane emissions. This study underscores the trade-offs between environmental sustainability, pasture productivity, and methane mitigation in pasture-based dairy systems, highlighting the need for integrated management approaches that balance ecological and production goals. Full article

Reducing enteric methane production from ruminant livestock has been positioned as a key intervention to reduce global greenhouse gas emissions. Bovaer©, a feed additive purported to reduce enteric methane emissions in dairy cows by nearly a third, has received regulatory authorization in many countries. However, there is a dearth of evidence on the consumer’s response to the use of such products. In the three weeks after 27 November 2024, there was a significant increase in media communications associated with the use of Bovaer© in Europe, and especially the United Kingdom (UK). This structured review of academic and gray literature and an iterative non-systematic survey of media discourse online explored and characterized the narratives that emerged in this three-week period of intense activity in both social media and mainstream media communications in order to critique the narratives and grammars within the public response and the implications for policymakers, industry and academia. The main narrative that emerged reflected the science-consumer tensions associated with the use of Bovaer© and the four sub-narratives shaping it (mainstream media influence and narrative framing, distrust in science and lack of relatability, conspiracy theories and fear-based narratives, consumer buycotts and market responses). Organizations adopting technological solutions to address ‘wicked’ societal problems need to understand the factors that trigger, amplify and attenuate social concern as expressed in mainstream and social media and need to adopt appropriate communication and dissemination activities to reduce the circulation of mis-dis-mal-information and promote information that is appropriate for multiple audiences and levels of understanding. Full article

This study investigates the relationship between methane emissions and physiological, behavioural, and haematological parameters in dairy cows during the transition period. Methane emissions were monitored alongside variations in rumination, feeding behaviour, and blood markers three weeks before calving, on calving day, and three weeks post-calving. Cows were retrospectively classified into low, medium, and high rumination groups according to their average daily rumination duration to investigate the effects of behavioural influences. During the prepartum period, the methane concentration was moderately positively correlated with drinking time (r = 0.41, p < 0.01) and weakly negatively correlated with chews per minute (r = −0.358, p < 0.05). Significant negative correlations were noted with chloride (r = −0.42, p < 0.01) and glucose levels (r = −0.41, p < 0.01). Following calving, methane emissions showed a positive correlation with haematocrit (r = 0.41, p < 0.01) and a negative correlation with haemoglobin (r = −0.47, p < 0.01). A haematological analysis revealed a notable negative correlation with platelets during calving (r = −0.64, p < 0.05). Individual dry matter intake (DMI) was recorded for each period, showing a significant drop on calving day. This intake fluctuation coincided with a significant rise in methane yield on calving day (p < 0.001). In the low rumination time group, methane was moderately negatively correlated with rumination chews (r = −0.52, p < 0.05), while in the high rumination group, a moderate negative correlation was observed with drinking gulps (r = −0.42, p < 0.05), and a weak negative correlation was observed with bolus events (r = −0.37, p < 0.05). Despite behavioural variations, methane emissions showed no substantial differences among groups with low, medium, and high rumination times, suggesting a minimal direct influence on rumination duration. These findings emphasise the complex interactions between feed intake, metabolism, and methane emissions, underscoring the importance of integrating behavioural and physiological indicators to develop targeted strategies for enteric methane mitigation while providing baseline data from healthy cows that could guide future research on methane emissions in cows undergoing postpartum metabolic disorders. Full article

Enteric methane emissions from ruminants substantially contribute to global greenhouse gas emissions, necessitating effective mitigation strategies that also support animal productivity. This study assessed the efficacy of a multi-component feed additive that combines medium-chain fatty acids (MCFAs), live yeast, plant-based agents, and Vitamin B, in reducing methane emissions, improving feed efficiency, and enhancing growth and immune function in sheep. Twenty crossbred castrated male sheep (52 ± 3.7 kg) were divided into control and treatment groups (n = 10 each), with the treatment group receiving grass pellets supplemented with the multi-component feed additive (20 g/day) for 71 days, including a 30-day acclimatisation period. Feed intake, methane emissions, growth performance, and blood parameters were monitored using BioControl pens, GreenFeed units, and haematological analyses. The treatment group exhibited a 24% increase in daily feed intake (p < 0.001) and a 22.2% reduction in methane yield per kg of dry matter ingested (p < 0.001), which could be attributed to MCFAs’ anti-methanogenic properties and yeast’s rumen modulation. However, no significant improvements were observed in daily live weight gain, feed conversion efficiency, or immune parameters, suggesting limited energy utilisation for growth. These findings highlight this novel multi-component feed additive as a promising strategy for methane mitigation in forage-based systems. Further dosage optimisation and dietary integration could enhance its application across ruminant species, contributing to sustainable livestock production. Full article

Reducing enteric methane emissions is critical for improving the sustainability of ruminant livestock production. In this study, we investigated the impact of the methane inhibitors 3-nitrooxypropanol (3-NOP) and canola oil, fed both individually and in combination, on the anaerobic gut fungi (AGF) of the rumen. Eight ruminally cannulated Angus heifers were used in a replicated double 4 × 4 Latin square over 28-day periods with a 2 (control, 3-NOP) × 2 (control, canola oil) factorial arrangement. Rumen samples were collected after 13 d dietary adaptation, and AGF communities were evaluated using amplicon sequencing of the D1/D2 region of the 28S rRNA (LSU) gene. Although 3-NOP reduced methane yield by approximately 32%, it did not substantially alter the diversity, composition, or overall abundance of the AGF community. In contrast, canola oil supplementation, either alone or combined with 3-NOP, markedly disrupted the fungal community. These treatments reduced overall fungal diversity and the abundance of key fiber-degrading taxa, such as Neocallimastix and Piromyces, while eliciting variable responses among less abundant genera. Furthermore, resilience analyses using control-diet-fed samples indicated that repeated perturbation impaired the recovery of some AGF taxa, leading to a shift in the composition of the fungal community. Overall, our findings suggest that 3-NOP offers a targeted methane mitigation strategy and does not alter the rumen AGF. In contrast, the addition of canola oil at levels that inhibit enteric methane emissions has a disruptive impact on the AGF community, contributing to reduced feed digestibility. Full article

This meta-analysis systematically evaluates the efficacy of dietary interventions for mitigating enteric methane production in ruminants through the application of advanced statistical methodologies. A comprehensive dataset comprising 119 peer-reviewed publications (2000–2024) was analyzed using robust variance estimation, multilevel modeling, and network meta-analysis to quantify intervention efficacy and identify moderating factors while properly accounting for within-study dependencies. The results demonstrate a clear efficacy hierarchy of macroalgae (51.0% reduction [95% CI: 37.0–63.0%]), 3-nitrooxypropanol (3-NOP; 30.6% [95% CI: 22.0–45.0%]), nitrate (16.0% [95% CI: 6.0–26.0%]), oils (14.7% [95% CI: 5.0–24.0%]), and phytochemicals (13.5% [95% CI: 4.0–22.0%]). The meta-regression analyses identified significant dose–response relationships for macroalgae (coefficient = −0.212, p < 0.001), 3-NOP (coefficient = −0.002, p < 0.001), nitrate (coefficient = −0.045, p = 0.004), and oils (coefficient = −0.031, p = 0.008), with animal type significantly moderating efficacy across interventions. The temporal trend analysis revealed significant efficacy improvements for macroalgae, nitrate, and phytochemicals (p < 0.05). The examination of intervention combinations identified synergistic effects for tannin + nitrate (ratio = 1.25) and 3-NOP + macroalgae (ratio = 1.12) combinations. The integration of efficacy data with implementation factors demonstrated substantial variation in practical viability, with 3-NOP, oils, and nitrate demonstrating the most favorable implementation profiles despite macroalgae’s superior efficacy. This comprehensive synthesis provides a quantitative foundation for developing targeted methane mitigation strategies across diverse ruminant production systems. Full article

Methane, a potent greenhouse gas, has a global warming potential over 84 times greater than carbon dioxide over its relevant lifespan. Current atmospheric methane concentrations are at a record high, significantly contributing to near-term climate warming. Agriculture, particularly livestock, is a major methane emitter, accounting for 40% of global total emissions, with enteric fermentation in ruminants accounting for 90% of agricultural methane emissions. The recent interest in mitigating these emissions has centered on seaweeds, such as Asparagopsis taxiformis, which contain bromoform, a bioactive compound shown to significantly reduce enteric methane production. However, bromoform raises environmental concerns including its potential carcinogenicity and ozone-depletion effects. This study systematically reviews the environmental and ozone-related impacts of scaling up seaweed production for enteric methane reduction in livestock. Key challenges include sustainability, biodiversity risks, and upstream emissions possibly offsetting the methane reduction gains. Animal health concerns, such as reduced weight gain and mucosal irritation, also warrant attention. Additionally, supply chain logistics, cultivation and harvesting practices, and bromoform retention remain underdeveloped. The limited assessment of the ozone depletion potential underscores the need for further research. These findings highlight the need for techno-feasibility and life cycle assessment before scaling up seaweed-based solutions. A broader approach to methane mitigation, beyond feed additives, is essential to ensure sustainable outcomes for livestock agriculture. Full article

Global beef demand will rise by 40 million tons in 30 years, increasing methane (CH₄) emissions. Pigweed (Amaranthus spinosus), an invasive weed abundant in southeastern U.S. pastures, may mitigate CH₄. Yet, its potential as a feed additive remains unexplored. The aim of this study was to evaluate the influence of pigweed and its extracts on ruminal fermentation and CH₄ production. For Exp 1, ruminal fluid from three American Aberdeen steers was incubated with 0, 2.5%, 5%, or 10% of diet dry matter (DM) of roots, stems, leaves, seeds, or the whole pigweed plant (WHO). In Exp 2, extracts from the leaves and WHO were incubated under the same conditions. For the first experiment, 2.5% of the roots, 5% of the leaves, and 10% of the WHO decreased acetate and butyrate concentrations (p < 0.01). In contrast, the WHO, leaves, and seeds at 2.5% of DM increased propionate concentration (p = 0.05). Increasing levels of WHO, leaves, and seeds quadratically reduced CH₄ (p < 0.001). The addition of 2.5 and 5% of leaves and WHO reduced in vitro CH4 production per gr of organic matter fermented (p < 0.01). In Exp 2, based on their CH₄ mitigation, the leaves and WHO were extracted, and their phenol (3.2 and 1.1 mg/g of DM, respectively) and flavonoid (19.7 and 1.9 mg/g of DM, respectively) contents were determined. Extracts from WHO (2.5%) decreased acetate and CH₄ (p < 0.05), while 5% inclusion decreased gas production and increased ruminal pH (p < 0.03). Leaf extracts (2.5%) increased propionate and reduced acetate: propionate (p < 0.05). The leaves and WHO extracts did not affect IVOMD at either inclusion level (p > 0.4). Extracts at 5% from WHO were more effective than that from leaves in reducing CH₄ (27% vs. 4%). The evidence suggests that the inclusion of 2.5 to 5% of WHO extracts shifts ruminal fermentation towards propionate-producing impairing methanogenesis, representing a sustainable strategy to mitigate CH₄. This hypothesis must be further assessed under in vivo supplementation of the extracts to beef cattle. Full article

Methane is a greenhouse gas with high warming potential, and ruminants like cattle and sheep are a major source of its emission. In the rumen, the first stomach compartment, diverse microorganisms and fauna live, including archaea, bacteria, protozoa, nematodes, and fungi. They participate in complex fermentation processes. During rumen fermentation, various gases are produced, dominantly hydrogen and carbon dioxide. In methanogenesis, methanogens utilize these two gases to produce methane as a byproduct, which burps out into the atmosphere. Therefore, interfering with this methanogenesis is a promising way of reducing methane. Supplementing feed containing clay minerals could be one of method to do so as ruminants naturally consume them as they graze, often called “geophagy”. This review discusses the role of clay minerals in enteric methane abatement, emphasizing the clay–microbial interaction in the rumen. In these interactions, clay minerals also serve as a carrier for other chemicals and influence microbial attachment. Elemental dissolution and cations from clay mineral and their buffering capacity can further influence microbial dynamics in rumen fluids. By combining insights from microbiology, soil science, and animal nutrition, this review provides an interdisciplinary view of rumen interactions. Findings from this review can help to develop a low-cost and safe clay feed supplement to reduce livestock methane emissions. Full article

This pilot study investigated whether reductions in enteric CH₄ emissions could be obtained without affecting dry matter intake (DMI) when iodoform was mixed into total mixed rations (TMRs). The experiment consisted of four periods of 14 d with four rumen-cannulated Holstein dairy cows. In the pre-period, no iodoform was added to TMR, while either 8, 16, or 20 mg iodoform/kg DM was added to TMR in the remaining periods in a change-over design. However, the experiment was not balanced across treatments and periods due to unexpected animal responses in the second period. Dry matter intake and gas exchange were measured the last 3 d in each period using respiration chambers. Rumen grab samples were collected for microbial analyses on d 14. Dry matter intake was unaffected by the addition of iodoform to TMR at or below 20 mg/kg DMI. Methane and H₂ yields (g/kg DMI) quadratically decreased (up to 46%) and increased (up to 1127%), respectively, with the increasing dose. This pilot study indicated that CH₄ reductions can be obtained with an addition of up to 20 mg iodoform/kg DM in the diets of dairy cows without affecting DMI. However, high iodine concentration in iodoform limits its use in commercial herds within the EU. Full article

A study was conducted on growing sheep to investigate the effect of two selected levels of biowaste of Padina gymnospora on feed intake, digestibility, daily enteric methane (CH₄) emission, growth performance, and rumen metagenome. We randomly divided the 18 growing male sheep into three groups of six animals each. The animals were fed on a basal diet comprising finger millet straw (Eleusine coracana) and a concentrate mixture in a 35:65 ratio. The sheep in the control group (C) were offered a concentrate mixture without waste, whereas the wheat bran in the concentrate mixture in test group I (A₂) and test group II (A₅) was replaced (w/w) with the biowaste of Padina gymnospora at a level of 3.07 and 7.69%, respectively. The biowaste of Padina gymnospora at the above levels in concentrate constituted 2 and 5% of the diet. A significant decrease of 28.4% in daily enteric CH₄ emission (g/d) was reported in the A₅ group, whereas the difference in daily enteric CH₄ emission between the C and A₂ & A₂ and A₅ groups did not prove significant. The inclusion of Padina gymnospora biowaste did not affect the nutrient intake and digestibility among the groups. The inclusion of Padina gymnospora biowaste in the A₅ group resulted in a significant reduction (p = 0.0012) in daily CH₄ emissions compared with group C; however, no significant differences were observed in daily CH₄ emissions between groups C–A₂ (p = 0.0793) and A₂–A₅ (p = 0.3269). Likewise, the adjustment of data to CH₄ emissions per 100 g of organic matter intake indicated a substantial decrease in the A₅ group relative to C. The energy loss in CH₄ as a percentage of GE relative to group C decreased significantly (−23.4%) in the A₅ group; however, this reduction was not associated with an increase in productivity, as almost similar average daily gain (p = 0.827) was observed in the groups. The replacement of wheat bran with the biowaste of Padina gymnospora significantly decreased the numbers of total protozoa and holotrichs in the A₅ group. Irrespective of the group, the Bacteroidota was the single largest phylum in the rumen metagenome, representing >60% of the microbiota. However, the abundance of Bacteroidota was similar among the groups. The methanogenic phyla Euryarchaeota was the 5th most abundant; however, it constituted only 3.14% of the metagenome. The abundance of Desulfovibrio was significantly higher in the A₅ group as compared with the control. In conclusion, the significant increase in the abundance of sulfate-reducing bacteria and reduction in protozoal numbers led to a significant reduction in CH₄ emissions with the incorporation of biowaste of Padina gymnospora at a 5% level of the diet. Full article

Enteric greenhouse gas (GHG) emissions represent a major challenge in livestock production, contributing significantly to global methane output. Various strategies have been explored to mitigate these emissions, including dietary modifications, feed additives, and genetic improvements. In the present study, the focus was on onion peel (OP), a byproduct of the onion processing industry that has shown promise as a natural feed supplement with potential methane-reducing properties. We evaluated the effect of different inclusion levels of OP at 2.5% (OP2.5), 5% (OP5), 7.5% (OP7.5), and 10% (OP10) on the in vitro fermentation of two diets: a total mixed ration referred to as high concentrate (HC), and corn silage referred to as high forage (HF). A 48 h batch culture experiment using a 2 × 3 × 5 factorial arrangement was conducted to assess total gas production (GP), methane (CH₄), carbon dioxide (CO₂), ammonia (NH₃), and hydrogen sulfide (H₂S) concentrations, and nutrient degradability. Measurements were taken at 6 h, 24 h, and 48 h of incubation. Significant additive × diet interactions were observed for most of the parameters. The HC diet produced more gas but less CH₄, CO₂, NH₃, and H₂S compared to the HF diet (p < 0.05). At 24 h of incubation, the OP at all levels increased CH₄, CO₂, NH₃, and H₂S concentrations in the HF diet (p < 0.05). The OP2.5 treatment had the lowest (quadratic effect, p < 0.05) degradable dry matter (dDM) in the HC diet, while the OP linearly (p < 0.001) increased degradable acid detergent fiber (dADF) in both diets. The lowest total volatile fatty acids (VFA) and acetate (quadratic effect, p = 0.027) were observed with the OP5 treatment in the HC diet, while OP5, OP7.5, and OP10 had lower total VFA concentration in the HC diet. At 48 h of incubation, the OP7.5 treatment increased (p < 0.05) GP and CH₄ and CO₂ production in the HC diet. However, the OP5 treatment had the lowest CH₄ production (quadratic effect, p = 0.027) in the HF diet. The highest dDM was observed with OP7.5 treatment (quadratic effect, p = 0.038) in the HC diet with lower values noted at different inclusion levels in the HF diet. Inclusion of OP had no effect on total VFA, and individual VFA in both diets. In conclusion, OP supplementation is more suitable for HF diets than HC diets. A 5% inclusion level is recommended to decrease ruminal CH₄production and improve nutrient degradability. Full article