Search Results (34)

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

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

Polygain™ (PG), a polyphenolic extract from sugarcane, has recently been identified as a potential additive to reduce methane (CH₄) emissions in livestock. This experiment examined the effects of PG on the enteric CH₄ emission from Holstein Friesian weaned calves. Calves were allocated to annual pasture grazing and received supplementary pellets (200 g/calf/day; Barastoc calf-rearer cubes—Ridley Corporation). The experimental design followed was a completely randomized design (CRD), comprising 24 female calves (4–5 months old) allocated to two equal groups; control (standard pellets) vs. treatment (pellets formulated by adding PG to control pellets to deliver 10 g PG/calf/day). Experimental diets were fed for three months between August and November 2023, including a two-week adaptation period. Calves were weighed at the start and at the end of the study. A GreenFeed (C-Lock Pvt Ltd.) emission monitoring unit (GEM) was used to measure GHG emissions from the experimental calves in their groups in a 2-day rotational cycle. During a visit to the GEM, the calves were encouraged to enter an enclosed area or individual feeding stall where enteric CH₄, CO₂, O₂, H₂, and H₂S measurements were taken. The results indicated a significant effect of PG supplementation on enteric methane emission in calves, with a lower production of CH₄ in calves supplemented with PG (26.66 ± 2.06 g/day) as compared to the control group (35.28 ± 1.39 g/day, p < 0.001). The CO₂/O₂ ratio in the treatment (235 ± 14) and control groups (183 ± 9.6) differed significantly (p < 0.001). Overall, PG supplementation (10 g/calf/day) reduced their average methane emission per day and did not adversely affect the growth and development of experimental calves, confirming its useful anti-methanogenic potential. Full article

A series of in vitro studies were conducted to explore the anti-methanogenic potential of five seaweeds collected from the Indian sea and to optimize the level(s) of incorporation of the most promising seaweed(s) into a straw and concentrate diet to achieve a significant reduction in methane (CH₄) production without disturbing rumen fermentation characteristics. A chemical composition analysis revealed a notable ash content varying between 55 and 70% in seaweeds. The crude protein content was highly variable and ranged between 3.25 and 15.3% of dry matter. Seaweeds contained appreciable concentrations of tannins and saponins. Among the seaweeds, Spyridia filamentosa exhibited significantly higher CH₄ production, whereas the percentage of CH₄ in total gas was significantly lower in the cases of Kappaphycus alvarezii and Sargassum wightii. The ranking of seaweeds in terms of CH₄ production (mL/g OM) is as follows: Sargassum wightii < Kappaphycus alvarezii < Acanthophora specifera < Padina gymnospora < Spyridia filamentosa. A remarkable decrease of 31–42% in CH₄ production was recorded with the incremental inclusion of Kappaphycus alvarezii at levels of 3–5% of the dry matter in the diet. The addition of Sargassum wightii led to a significant decrease of 36–48% in CH₄ emissions when incorporated at levels of 4–5% of dry matter, respectively. The findings of this study revealed a significant decrease in the numbers of total protozoa and Entodinomorphs, coupled with increasing abundances of sulfate-reducing microbes and minor methanogens. Metagenome data revealed that irrespective of the seaweed and treatment, the predominant microbial phyla included Bacteroidota, Bacillota, Pseudomonadota, Actinomycetota, Fibrobacterota, and Euryarchaeota. The prevalence of Methanobrevibacter was similar across treatments, constituting the majority (~79%) of the archaeal community. The results also demonstrated that the supplementation of Kappaphycus alvarezii and Sargassum wightii did not alter the feed fermentation pattern, and therefore, the reduction in CH₄ production in the present study could not be attributed to it. Animal studies are warranted to validate the extent of reduction in CH₄ production and the key processes involved by supplementation with Kappaphycus alvarezii and Sargassum wightii at the recommended levels. Full article

Enteric methanogenesis in ruminants is identified as one of the primary anthropogenic sources of total atmospheric methane. Recent evidence suggests that rumen methanogenesis is significantly suppressed by lovastatin. Nevertheless, it has not been reported whether the methane reduction by lovastatin depends on ruminant livestock type, nor has fiber degradability been examined. The current research aimed to analyze the in vitro effect of lovastatin on the major fermentation end-products, gas production (GP) kinetics, and fiber degradation of a forage-based diet using rumen inoculum from sheep, goats, and cows. The experiment was conducted as a 3 × 3 factorial arrangement of treatments (dose of lovastatin: 0, 80, and 160 mg/L and three inoculum sources) in a completely randomized design. The results suggested that lovastatin did not affect the GP kinetics parameters. The anti-methanogenic properties of lovastatin were variable depending on dose and inoculum source. Lovastatin demonstrated a superior methane-lowering effect in sheep rumen inoculum compared with goat and cow inocula. The total volatile fatty acid (VFA) production was unaffected by lovastatin, but changes in acetate and valerate proportions were registered. Remarkably, lovastatin decreased the NH3-N concentration with goat and sheep inocula and the in vitro neutral fiber detergent (NDF) degradation for all inoculum sources. Full article

Almond hulls (AH) are frequently used in dairy ruminant feeding, but information on variability of their nutritive value and their potential effects on CH₄ production is still scarce. The influence of almond variety (Guara vs. Soleta) on chemical composition and energy value of AH was investigated using 10 samples per variety collected in 2 consecutive years. Guara-AH had greater (p ≤ 0.015) ash, protein, and fat content, but lower (p ≤ 0.001) fiber than Soleta-AH. The metabolizable energy content estimated from chemical composition and in vitro gas production was 8.5% greater for Guara than for Soleta samples. Harvesting year significantly affected most of the chemical fractions. The in vitro ruminal fermentation of diets for dairy ruminants including increasing amounts of dried AH (8, 16 and 24% of the total diet; fresh matter basis) indicated that AH can be included up to 16% of the diet, partially substituting corn, wheat bran and sugar beet pulp without detrimental effects on in vitro volatile fatty acid (VFA) production. In contrast, when AH replaced alfalfa hay and corn, VFA production was reduced at all levels of AH inclusion. No antimethanogenic effects of AH were detected in the in vitro incubations. Full article

Livestock producers need new technologies to maintain the optimal health and well-being of their animals while minimizing the risks of propagating and disseminating pathogenic and antimicrobial-resistant bacteria to humans or other animals. Where possible, these interventions should contribute to the efficiency and profitability of animal production to avoid passing costs on to consumers. In this study, we examined the potential of nitroethane, 3-nitro-1-propionate, ethyl nitroacetate, taurine and L-cysteinesulfinic acid to modulate rumen methane production, a digestive inefficiency that results in the loss of up to 12% of the host’s dietary energy intake and a major contributor of methane as a greenhouse gas to the atmosphere. The potential for these compounds to inhibit the foodborne pathogens, Escherichia coli O157:H7 and Salmonella Typhimurium DT104, was also tested. The results from the present study revealed that anaerobically grown O157:H7 and DT104 treated with the methanogenic inhibitor, ethyl nitroacetate, at concentrations of 3 and 9 mM had decreased (p < 0.05) mean specific growth rates of O157:H7 (by 22 to 36%) and of DT104 (by 16 to 26%) when compared to controls (0.823 and 0.886 h⁻¹, respectively). The growth rates of O157:H7 and DT104 were decreased (p < 0.05) from controls by 31 to 73% and by 41 to 78% by α-lipoic acid, which we also found to inhibit in vitro rumen methanogenesis up to 66% (p < 0.05). Ethyl nitroacetate was mainly bacteriostatic, whereas 9 mM α-lipoic acid decreased (p < 0.05) maximal optical densities (measured at 600 nm) of O157:H7 and DT104 by 25 and 42% compared to controls (0.448 and 0.451, respectively). In the present study, the other oxidized nitro and organosulfur compounds were neither antimicrobial nor anti-methanogenic. Full article

Despite the extensive research conducted on ruminal methanogens and anti-methanogenic intervention strategies over the last 50 years, most of the currently researched enteric methane (CH₄) abatement approaches have shown limited efficacy. This is largely because of the complex nature of animal production and the ruminal environment, host genetic variability of CH₄ production, and an incomplete understanding of the role of the ruminal microbiome in enteric CH₄ emissions. Recent sequencing-based studies suggest the presence of methanogenic archaea in extra-gastrointestinal tract tissues, including respiratory and reproductive tracts of cattle. While these sequencing data require further verification via culture-dependent methods, the consistent identification of methanogens with relatively greater frequency in the airway and urogenital tract of cattle, as well as increasing appreciation of the microbiome–gut–organ axis together highlight the potential interactions between ruminal and extra-gastrointestinal methanogenic communities. Thus, a traditional singular focus on ruminal methanogens may not be sufficient, and a holistic approach which takes into consideration of the transfer of methanogens between ruminal, extra-gastrointestinal, and environmental microbial communities is of necessity to develop more efficient and long-term ruminal CH₄ mitigation strategies. In the present review, we provide a holistic survey of the methanogenic archaea present in different anatomical sites of cattle and discuss potential seeding sources of the ruminal methanogens. Full article

The aim of this study comprises the effect of fermented grape pomace (FGP) in experimental total mixed rations (TMR) at different rates (0, 7.5%, 15%, and 22.5%) on the in vitro cumulative gas production (6th, 12th, 18th and 24th hours), methane production, ruminal fermentation values, pH and ammonia-nitrogen and straight and branched short-chain fatty acids (SCFA and BCFA) concentration. The method of in vitro total gas production was carried out in glass syringes. Ruminal in vitro methane production linearly decreased by adding up to 22.5% FGP in experimental TMR (p < 0.05). The molarities of acetic, propionic, butyric, and valeric acids in the in vitro fermentation fluid linearly decreased with the addition of FGP to TMR (p < 0.05). FGP up to 22.5% in experimental TMRs decreased the molarity of iso-valeric acid and iso-butyric acid from BSCFAs (p < 0.05). As a result, it was concluded that the use of FGP, containing a low level of total condensed tannins (TCTs), up to 22.5% in the experimental TMR based on dry matter (DM) did not adversely affect the in vitro ruminal fermentation value and had an anti-methanogenic effect. In addition, some SCFA (acetic, propionic, butyric, and valeric acids) molarities and iso-acid BSCFA (iso-butyric and iso-valeric acid) did not change up to 15% rate of FGP in the ration. Still, these values decreased by using a 22% rate of FGP. The dose-dependent effect of FGP on ruminal iso-acids has been associated with the ability of TCTs to inhibit ruminal protein degradation partially. Full article

Methane production is a waste of energy for ruminants and contributes to greenhouse gas emissions. The objective of the present study was to evaluate the anti-methanogenic effect of increasing the supplementation levels of Cymbopogon citratus (CC) on the dry matter intake (DMI), digestibility, methane (CH₄) production, and partitioning of the gross energy intake in growing beef heifers fed with a diet high in forage (68.6% forage: 31.4% concentrate). An experiment was conducted using Holstein × Charolais heifers distributed in a 4 × 4 Latin square design. The experimental treatments were: (1) control diet (CO), (2) CO + 30 g CC DM/d, (3) CO + 60 g CC DM/d CC, and (4) CO + 90 g CC DM/d. A reduction of 22.4% in methane yield (CH₄ g/kg DMI) and a reduction of 21.2% in the Ym factor was observed with the 30 CC treatment (p ≤ 0.05). However, no significant differences (p > 0.05) were observed for the total daily CH₄ production, DMI, nutrient digestibility, and gross energy intake partitioning in the heifers. Therefore, we concluded that the supplementation of 30 g CC DM/d reduced the CH₄ yield without affecting the animal performance. However, the anti-methanogenic properties of Cymbopogon citratus deserve more investigation. Full article

Simulation models represent a low-cost approach to evaluating agricultural systems. In the current study, the precision and accuracy of the RUMINANT model to predict dry matter intake (DMI) and methane emissions from beef cattle fed tropical diets (characteristic of Colombia) was assessed. Feed intake (DMI) and methane emissions were measured in Brahman steers housed in polytunnels and fed six forage diets. In addition, DMI and methane emissions were predicted by the RUMINANT model. The model’s predictive capability was measured on the basis of precision: coefficients of variation (CV%) and determination (R², percentage of variance accounted for by the model), and model efficiency (ME) and accuracy: the simulated/observed ratio (S/O ratio) and slope and mean bias (MB%). In addition, combined measurements of accuracy and precision were carried out by means of mean square prediction error (MSPE) and correlation correspondence coefficient (CCC) and their components. The predictive capability of the RUMINANT model to simulate DMI resulted as valuable for mean S/O ratio (1.07), MB% (2.23%), CV% (17%), R² (0.886), ME (0.809), CCC (0.869). However, for methane emission simulations, the model substantially underestimated methane emissions (mean S/O ratio = 0.697, MB% = −30.5%), and ME and CCC were −0.431 and 0.485, respectively. In addition, a subset of data corresponding to diets with Leucaena was not observed to have a linear relationship between the observed and simulated values. It is suggested that this may be related to anti-methanogenic factors characteristic of Leucaena, which were not accounted for by the model. This study contributes to improving national inventories of greenhouse gases from the livestock of tropical countries. Full article

The red seaweed Asparagopsis taxiformis is a promising ruminant feed additive with anti-methanogenic properties that could contribute to global climate change solutions. Genomics has provided a strong foundation for in-depth molecular investigations, including proteomics. Here, we investigated the proteome of A. taxiformis (Lineage 6) in both sporophyte and gametophyte stages, using soluble and insoluble extraction methods. We identified 741 unique non-redundant proteins using a genome-derived database and 2007 using a transcriptome-derived database, which included numerous proteins predicted to be of fungal origin. We further investigated the genome-derived proteins to focus on seaweed-specific proteins. Ontology analysis indicated a relatively large proportion of ion-binding proteins (i.e., iron, zinc, manganese, potassium and copper), which may play a role in seaweed heavy metal tolerance. In addition, we identified 58 stress-related proteins (e.g., heat shock and vanadium-dependent haloperoxidases) and 44 photosynthesis-related proteins (e.g., phycobilisomes, photosystem I, photosystem II and ATPase), which were in general more abundantly identified from female gametophytes. Forty proteins were predicted to be secreted, including ten rhodophyte collagen-alpha-like proteins (RCAPs), which displayed overall high gene expression levels. These findings provide a comprehensive overview of expressed proteins in A. taxiformis, highlighting the potential for targeted protein extraction and functional characterisation for future biodiscovery. Full article

Plant phytochemicals are an important area of study in ruminant nutrition, primarily due to their antimethanogenic potentials. Plant extract yields, their bioactive compounds and antimethanogenic properties are largely dependent on the nature of the extractive solvents. This study evaluated the yields and phytochemical constituents of four plant extracts, as affected by the aqueous-methanolic (H₂O-CH₃OH) extraction and their antimethanogenic properties on the in vitro methane production. The plant extracts included Aloe vera, Jatropha curcas, Moringa oleifera, and Piper betle leaves with three levels of extractions (70, 85, and 100% CH₃OH). The crude plant extract yields increased with the increasing amount of water. M. oleifera crude extracts yields (g/10 g) increased from 3.24 to 3.92, A. vera, (2.35 to 3.11) J. curcas (1.77 to 2.26), and P. betle (2.42 to 3.53). However, the identified and quantified metabolites showed differing degrees of solubility unique to their plant leaves in which they exist, while some of the metabolites were unaffected by the extraction solvents. The methane mitigating potentials of these extracts were evaluated as additives on Eragrostis curvula hay at a recommended rate of 50 mg kg⁻¹ DM. The plant extracts exhibited antimethanogenic properties to various degrees, reducing (p < 0.05) in vitro methane production in the tested hay, A. vera, J. curcas, M. oleifera and P. betle reduced methane emission by 6.37–7.55%, 8.02–11.56%, 12.26–12.97, and 5.66–7.78 respectively compared to the control treatment. However, the antimethanogenic efficacy, gas production and organic matter digestibility of the plant extracts were unaffected by the extraction solvents. Metabolites, such as aloin A, aloin B and kaempferol (in A. vera), apigenin, catechin, epicatechin, kaempferol, tryptophan, procyanidins, vitexin-7-olate and isovitexin-7-olate (in J. curcas), alkaloid, kaempferol, quercetin, rutin and neochlorogenic acid (in M. oleifera) and apigenin-7,4′-diglucoside, 3-p-coumaroylquinic acid, rutin, 2-methoxy-4-vinylphenol, dihydrocaffeic acid, and dihydrocoumaric acid (in P. betle) exhibited a methane reducing potential and hence, additional studies may be conducted to test the methane reducing properties of the individual metabolites as well as their combined forms. Plant extracts could be more promising, and hence, further study is necessary to explore other extraction methods, as well as the encapsulation of extracts for the improved delivery of core materials to the target sites and to enhance methane reducing properties. Furthermore, the use of 70% aqueous extraction on M. oleifera leaf is recommended for practical use due to the reduced cost of extractive solvents, the lower cost and availability of Moringa plants in South Africa, especially in Gauteng Province. Furthermore, 70% aqueous-methanolic extractions of A. vera, J. curcas, and P. betle are recommended for practical use in regions where they exist in abundance and are cost effective. Full article

The use of medicinal plants and their extracts has recently attracted the attention of many researchers as a methane (CH₄) mitigation strategy. This study evaluated the relationship of agronomic traits of Moringa accessions with in vitro gas production measurements and feed digestibility from ruminants. Twelve Moringa accessions were grown at the Roodeplaat experimental site of the Agricultural Research Council in Pretoria, South Africa. Agronomic traits, such as seedling survival rate, leaf yield, canopy and stem diameter, plant height, number of primary branches, plant vigor, greenness, chlorosis, disease and pest incidences were recorded. The leaves were harvested in the fifth month after transplanting to the field. Freeze-dried leaves were extracted with methanol, and their total phenolic and total flavonoid contents were determined. The extract was applied at a dose of 50 mg/kg of dry matter (DM) feed for in vitro gas production studies. Most of the growth and agronomic traits, i.e., seedling survival rate, leaf yield, canopy diameter, plant height, number of primary branches, the score of plant vigor, and greenness, total phenolics and flavonoids were significantly different among the accessions except for stem diameter and chlorosis score. All accession leaf extracts significantly reduced the total gas and CH₄ production compared with the control with equal or higher in vitro organic matter digestibility. Higher CH₄ inhibition was obtained in Moringa oleifera (M. oleifera) A3 (28.4%) and A11 (29.1%), whereas a lower inhibition was recorded in A1 (17.9%) and A2 (18.2%). The total phenolic (0.62) and total flavonoid (0.71) contents as well as most agronomic traits of the accessions were positively correlated with the CH₄ inhibition potential of the accessions. Moringa oleifera accessions A3, A8 and A11 resulted in higher in vitro CH₄ inhibition potential and improved organic matter digestibility of the feed with equal or higher adaptability performances in the field. Thus, there is a possibility of selecting Moringa accessions for higher antimethanogenic activity without compromising the feed digestibility by selecting for higher total phenolics, total flavonoids and agronomic performances traits. There is a need for further study to determine the long-term adaptability of promising accessions in the study area with concurrent antimethanogenesis efficacy when used in the diet of ruminant animals. Full article

This paper analyzes the mitigation of enteric methane (CH₄) emissions from ruminants with the use of feed additives inhibiting rumen methanogenesis to limit the global temperature increase to 1.5 °C. A mathematical simulation conducted herein predicted that pronounced inhibition of rumen methanogenesis with pure chemicals or bromoform-containing algae with an efficacy higher than that obtained in most studies can be important to limiting global temperature increase by 2050 to 1.5 °C but will likely need to be accompanied by improved production efficiency and other mitigation measures. Currently, the most important limitations to the adoption of antimethanogenic feed additives are increased feeding cost without a consistent return in production efficiency and achieving sustained delivery of inhibitors to grazing animals, especially in extensive systems. Economic incentives could be applied in some countries to favor adoption of inhibitors. Changes in rumen microbial and whole animal metabolism caused by inhibiting methanogenesis could potentially be used to make the methanogenesis inhibition intervention cost-effective, although research in this direction is unlikely to yield results in the short term. Future research directions to maximize the adoption and efficacy of inhibitors of methanogenesis are examined. Full article