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The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The purpose of this experiment was to determine if nicotinic acid (NA) effects on dairy cows and rumen microbial characteristics are forage-type dependent (corn silage, CS; grass silage, GS). Four late-lactation (DIM = 225 ± 12 d) Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. The main effects were a CS (66.10% CS) based diet or a GS (79.59%) based diet with or without 12 g/d NA. Each experimental period lasted for 28 d. Milk production and milk components, blood metabolites, apparent total-tract nutrient digestibilities, minutes rumen pH were below 5.8 as an indicator of ruminal acidosis, and body temperature changes were analyzed as indicators of heat stress. Nicotinic acid supplementation did not improve apparent total-tract nutrient digestibility. Feeding a GS-based diet improved NDF and hemicellulose digestibility. Feeding a CS-based diet increased the apparent total-tract digestibility of fat, and minutes rumen pH below 5.8 for a greater proportion of the time. The CS-based diet also improved milk yield, milk fat and protein yields, and ECM yield; however, somatic cell count and BHB were also increased. Supplementing NA tended to decrease nonesterified fatty acids, especially when combined with GS where DMI was low. There was a trend for the total protozoa population to increase when GS and NA were fed but decreased when CS and NA were fed. Nicotinic acid tended to decrease rumen protozoal populations of Dasytricha , but increased populations of Ophryoscolex and Diplodiniinae with GS diets and decreased with CS diets. Entodiniinae were increased with CS but NA had no effect. Body temperature was increased when a CS-based diet was fed when compared with a GS-based diet. More research is needed to determine how NA can affect rumen microbial protein synthesis and what kind of diets will provide the optimum effect. [ABSTRACT FROM AUTHOR]

ABSTRACT: The purpose of this experiment was to determine if nicotinic acid (NA) effects on dairy cows and rumen microbial characteristics are forage-type dependent (corn silage, CS; grass silage, GS). Four late-lactation (DIM = 225 ± 12 d) Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. The main effects were a CS (66.10% CS) based diet or a GS (79.59%) based diet with or without 12 g/d NA. Each experimental period lasted for 28 d. Milk production and milk components, blood metabolites, apparent total-tract nutrient digestibilities, minutes rumen pH were below 5.8 as an indicator of ruminal acidosis, and body temperature changes were analyzed as indicators of heat stress. Nicotinic acid supplementation did not improve apparent total-tract nutrient digestibility. Feeding a GS-based diet improved NDF and hemicellulose digestibility. Feeding a CS-based diet increased the apparent total-tract digestibility of fat, and minutes rumen pH below 5.8 for a greater proportion of the time. The CS-based diet also improved milk yield, milk fat and protein yields, and ECM yield; however, somatic cell count and BHB were also increased. Supplementing NA tended to decrease nonesterified fatty acids, especially when combined with GS where DMI was low. There was a trend for the total protozoa population to increase when GS and NA were fed but decreased when CS and NA were fed. Nicotinic acid tended to decrease rumen protozoal populations of Dasytricha, but increased populations of Ophryoscolex and Diplodiniinae with GS diets and decreased with CS diets. Entodiniinae were increased with CS but NA had no effect. Body temperature was increased when a CS-based diet was fed when compared with a GS-based diet. More research is needed to determine how NA can affect rumen microbial protein synthesis and what kind of diets will provide the optimum effect.

Abstract Background Grasslands are the primary source of forage for ruminants. Legal restrictions on nitrogen fertilization force farmers to optimize nitrogen use efficiency (NUE) of grassland and protein quality in grass silage. Methods The present study included grassland data from 10 dairy farms in Flanders. For each grassland field, the presence of clover was determined based on the seed mixture composition. Soil and manure were sampled before the first application and analyzed to determine plant available N content. The annual NUE was calculated for each field possible (n = 28). Prewilted grass samples were taken just before ensiling (n = 65) and grass silage samples (n = 41) were collected from the same fields. Results Clover fields demonstrated improved NUE due to a lower nitrogen input from fertilizers compared to pure grassland fields (75 vs. 265 kg ha−1). The protein quality of the grass silage was positively correlated with the organic matter digestibility, sugar content, and dry matter content of the prewilted grass. Conversely, crude ash content had a negative effect. Conclusions These findings underscore the importance and potential of clover and the practical feasibility of optimizing grassland management to improve both NUE in grasslands and protein quality of the silage.

ABSTRACT: The effects of grass silage and red clover silage on milk fatty acid (FA) composition are extensively studied, but little is known of their effects on minor lipid constituents of milk fat globule membrane. We investigated the effects of forage:concentrate (FC) ratio in grass silage-based diets and forage type (grass silage vs. red clover silage) on selected molecular species of milk phospholipids (PL) and the FA composition of PL. Ten multiparous Nordic Red cows were offered following dietary treatments: grass silage-based diets containing 70:30 (HG) or 30:70 (LG) FC ratio or a red clover silage-based diet (RC) comprising 50:50 FC ratio on a dry matter basis. The most abundant molecular species within the phosphatidylcholines was 16:0–18:1 phosphatidylcholine that was increased by 18% in HG compared with LG milk. Dietary treatments did not affect the relative proportion of 18:1–18:1+18:0–18:2 phosphatidylethanolamine that was the most prevalent species (ca. 44%–45%) in that class. We identified the d18:1–22:0 sphingomyelin as the most abundant sphingomyelin species that tended to increase in HG milk compared with LG. The FC ratio did not affect the relative proportions of saturated FA nor monounsaturated FA in PL, but the proportion of cis-9 18:1 was elevated in HG versus LG milk, whereas the proportion of 18:2n-6 was 50% higher in LG versus HG milk. The RC diet increased monounsaturated FA and 18:3n-3 levels in PL compared with grass silage-based diets and decreased the relative proportion of saturated FA. However, the RC diet did not affect the relative proportion of polyunsaturated FA in PL, although red clover silage typically increases the proportion of polyunsaturated FA in milk fat. This study provides valuable knowledge of the minor lipid components in milk on species level in relation to common feeding strategies in high-forage systems.

Ensilage of refused fruit with forage is a viable approach to increase resource use in ruminant feed. The objective of this study was to investigate the impact of ensiling refused melon fruit (RMF) with Canarana grass on the intake, apparent digestibility, serum biochemistry, performance, carcass traits, and meat attributes of feedlot lambs. Four distinct silage treatment types were prepared by ensiling RMF at 0 g/kg (control), 70 g/kg, 140 g/kg, and 210 g/kg (as fed) with Canarana grass. Twenty-eight male Santa Inês lambs (7 lambs per treatment), initially weighing 22.3 ± 1.0 kg at 120 days of age, were distributed in a completely randomized design and confined for a total of 96 days, including a 23-day adaptation period and 73 experimental days in a feedlot. The lambs received the treatment-silage in diets as a complete mixture with a roughage: concentrate ratio of 30:70. The inclusion of RMF in Canarana grass ensilage decreased (P < 0.05) the lambs’ intake of dry matter, crude protein and metabolisable energy. The inclusion of RMF in ensilage had a quadratic effect (P < 0.05) on the digestibility of non-fibrous carbohydrates. The serum total protein and cholesterol levels decreased (P < 0.05) with the inclusion of RMF in the ensilage, but we observed no effect on the final weight and average daily gain of the lambs. The feed efficiency increased (P < 0.05) by including RMF in the Canarana grass ensilage. The RMF in the ensilage did not influence cold carcass weight and yield. The fat content of the meat decreased (P < 0.05) with the inclusion of RMF in the ensilage. It is recommended the inclusion of up to 210 g/kg of RMF in Canarana grass ensilage to increase feed efficiency and avoid impacts on the performance and carcass attributes of confined lambs. [ABSTRACT FROM AUTHOR]

The effects of grass silage and red clover silage on milk fatty acid (FA) composition are extensively studied, but little is known of their effects on minor lipid constituents of milk fat globule membrane. We investigated the effects of forage:concentrate (FC) ratio in grass silage-based diets and forage type (grass silage vs. red clover silage) on selected molecular species of milk phospholipids (PL) and the FA composition of PL. Ten multiparous Nordic Red cows were offered following dietary treatments: grass silage-based diets containing 70:30 (HG) or 30:70 (LG) FC ratio or a red clover silage-based diet (RC) comprising 50:50 FC ratio on a dry matter basis. The most abundant molecular species within the phosphatidylcholines was 16:0–18:1 phosphatidylcholine that was increased by 18% in HG compared with LG milk. Dietary treatments did not affect the relative proportion of 18:1–18:1+18:0–18:2 phosphatidylethanolamine that was the most prevalent species (ca. 44%–45%) in that class. We identified the d18:1–22:0 sphingomyelin as the most abundant sphingomyelin species that tended to increase in HG milk compared with LG. The FC ratio did not affect the relative proportions of saturated FA nor monounsaturated FA in PL, but the proportion of cis -9 18:1 was elevated in HG versus LG milk, whereas the proportion of 18:2n-6 was 50% higher in LG versus HG milk. The RC diet increased monounsaturated FA and 18:3n-3 levels in PL compared with grass silage-based diets and decreased the relative proportion of saturated FA. However, the RC diet did not affect the relative proportion of polyunsaturated FA in PL, although red clover silage typically increases the proportion of polyunsaturated FA in milk fat. This study provides valuable knowledge of the minor lipid components in milk on species level in relation to common feeding strategies in high-forage systems. [ABSTRACT FROM AUTHOR]

Background: Local sward dieback, especially in grasslands on peat soil, in response to the extreme 2018/2019 drought demonstrates climate vulnerability of intensive grasslands in northern Central Europe. Methods: We explore the influence of microtopography, that is, the within‐field mosaic of depressions and elevated patches, on soil volumetric moisture content, standing biomass and biomass crude protein (CP) and fibre content in intensively managed grassland on peat soil in a moist year (2021) and a dry year (2022) for quantifying small‐scale spatial heterogeneity within a field. Results: We found high within‐field variation in soil moisture, biomass and forage quality and a moisture dependence of productivity that was stronger in the dry year. CP ranged from 10% to 25% within a field, being lower in moist depressions than elevated patches in the wet (but not in the dry) summer. Conclusions: The moister depressions help to limit the overall productivity decline in dry summers, whereas, in moist summers, the higher dry patches produce more protein‐rich forage than the depressions, where productivity is higher but quality is lower. We recommend adapting grassland management to this heterogeneity through spatially differentiated management regimes in order to better cope with an increasingly drier and more variable climate. [ABSTRACT FROM AUTHOR]

Background: Grasslands are the primary source of forage for ruminants. Legal restrictions on nitrogen fertilization force farmers to optimize nitrogen use efficiency (NUE) of grassland and protein quality in grass silage. Methods: The present study included grassland data from 10 dairy farms in Flanders. For each grassland field, the presence of clover was determined based on the seed mixture composition. Soil and manure were sampled before the first application and analyzed to determine plant available N content. The annual NUE was calculated for each field possible (n = 28). Prewilted grass samples were taken just before ensiling (n = 65) and grass silage samples (n = 41) were collected from the same fields. Results: Clover fields demonstrated improved NUE due to a lower nitrogen input from fertilizers compared to pure grassland fields (75 vs. 265 kg ha−1). The protein quality of the grass silage was positively correlated with the organic matter digestibility, sugar content, and dry matter content of the prewilted grass. Conversely, crude ash content had a negative effect. Conclusions: These findings underscore the importance and potential of clover and the practical feasibility of optimizing grassland management to improve both NUE in grasslands and protein quality of the silage. [ABSTRACT FROM AUTHOR]

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The forage silage can not only prevent the loss of nutrients, but also reduce the volume of feed and solve the problem that the forage grass is difficult to preserve. However, many grass have the problems of high water and low sugar content. Thus, the quality of direct silage is lower. Additives can improve the quality of silage and the commonly used silage additives include enzyme and lactic acid bacteria preparation. How to play the advantages of different silage additives and improve the quality of silage are crucial to increase the utilization rate of forage grass. This review paper introduced the effects characteristics of silage additives, concluded the effects of additives on fermentation quality, nutritional value and aerobic stability of forage silage, and emphatically summarized the effects of additives on microbial diversity of forage silage. [ABSTRACT FROM AUTHOR]

ABSTRACT This study aimed to evaluate the effects of diets containing elephant grass genotypes silages as exclusive roughage on leg tissue composition, and physicochemical characteristics of meat of lambs. Twenty-four crossbred male lambs with an average initial body weight of 20.29±2.66kg were distributed in a complete randomized design with three treatments and eight replicates. The treatments consisted of three silages of elephant grass genotypes (IRI-381, Elephant B or Mott), without additives or wilting, as the only roughage. The diets did not affect (P>0.05) the dry matter (898.70±60.10 g/day), crude protein (128.93±6.91g/day), total digestible nutrients (690.20±91.82g/day) intakes, body weight at slaughter (24.83±2.79kg), and carcass yields (P>0.05). The tissue composition of the leg did not differ significantly between silages of elephant grass genotypes (P>0.05). No difference (P>0.05) for the physicochemical characteristics of meat from lambs fed diets tested was observed. Therefore, our results indicate that diets containing 50% elephant grass genotypes silages (IRI-381, Elephant B or Mott), harvested at 60 days of growth, have potential for use in lambs feeding.

Plant lipids in the diet are known to modify milk fatty acid (FA) composition and mitigate ruminal methane emissions. The objective of the present work was to examine the potential of milled rapeseeds and oats to decrease both milk saturated FAs and ruminal methane emissions in practical farm settings. In the pilot study, six Finnish Ayrshire cows were fed a control diet for 3 weeks, which was then followed by a lipid-rich test diet for 3 weeks. The experimental diets were based on grass silage supplemented with barley and rapeseed meals in the control diet and with oats and milled rapeseeds in the test diet. The lipid inclusion rate was 55 g/kg dry matter (DM). In the main study, the whole Finnish Ayrshire research herd in milk (n = 49–59) was used in a switch-back-designed study. The cows were fed a control diet for 3 weeks, then a test diet for 4 weeks, and, finally, a control diet for 3 weeks. The diets were the same as in the pilot study except for a lower lipid inclusion level of 50 g/kg DM. The test diet decreased DM intake by 15% and energy-corrected milk (ECM) yield by 13% in the pilot study. The adjustment of supplemental lipids from 55 g/kg to 50 g/kg DM was successful, as the DM intake decreased only by 4% relative to the control diet in the main study. Furthermore, the yields of milk, lactose, protein, and fat were also unaffected by dietary lipids in the main study. The milk fat composition was significantly altered in both studies. The milk fat saturated FAs were decreased by 16%–20% in the test diet, mainly due to the de novo FAs of 6- to 16-carbons (a reduction of 22%–48%). Milk fat cis-9 18:1 was increased by 63%–78% in the test diet relative to the control. Dairy products’ (milk, butter, and cheese) organoleptic quality was not compromised by the modified lipid profile. Ruminal methane and hydrogen intensities (n = 23; g or mg/kg ECM) were 20% and 39% lower, respectively, in the test diet than in the control diet. This reduction can be attributed to a lower amount of organic matter fermented in the rumen, as indicated by the lower DM intake and nutrient digestibility.

Maintenance of urban green infrastructure generates a large amount of biomass that can be considered a valuable feedstock for biogas production. This study aims to determine the effect of the cutting time and method of substrate preservation on the specific methane yield (SMY) of urban grass collected from road verges and median strips between roadways in wet (WF) and dry fermentation (DF) technology. The grass was collected three times in a growing season, including in spring, summer, and autumn. The biochemical methane potential (BMP) test was performed on fresh grass, grass ensiled without additives, and grass ensiled with microbiological additives. In addition, the energy potentially produced from biogas and the avoided CO2 emissions were calculated. The highest SMY (274.18 ± 22.59 NL kgVS−1) was observed for the fresh grass collected in spring and subjected to WF. At the same time, the lowest CH4 production (182.63 ± 0.48 NL kgVS−1) was found in the grass ensiled without additives, collected in summer, and digested in DF technology. A comparison of the SMY obtained from the same grass samples in the WF and DF technologies revealed that higher CH4 yields were produced in WF. The electricity and heat production were affected by the time of grass cutting, ensilage method, and AD technology. Generally, less electricity but more heat was produced in DF technology. The least electricity (469–548 kWh tDM−1) was produced from the grass cut in spring and subjected to DF, while the most electricity (621–698 kWh tDM−1) was obtained from the grass collected in autumn and subjected to WF. In the case of heat production, the situation was reversed. The least heat (1.4–1.9 GJ tDM−1) was produced by the grass collected in spring and subjected to WF, while the most heat (2.2–2.7 GJ tDM−1) was produced by the grass collected in autumn and subjected to DF. Ensilage decreased the electricity and heat production in almost all the cuttings. The total reduction in CO2 emissions may amount to 2400 kg CO2 per 1 hectare of road verges. This significant reduction demonstrates that the use of grass from roadside verges in biogas plants should be considered a feasible option. Even though urban grass should be considered a co-substrate only, it can be a valuable feedstock that may partially substitute energy crops and reduce the area needed for energy purposes. Our results reveal that biogas production from the grass waste in WF technology is a stable process. The cutting time and preservation method do not affect the AD process. In DF technology, fresh grass, especially from the late growing season used as feedstock, extends the time of biomass decomposition and, therefore, should be avoided in a real-life biogas plant. [ABSTRACT FROM AUTHOR]

Fava bean offers a sustainable home-grown protein source for dairy cows, but fava bean protein is extensively degraded in the rumen and has low Met concentration. We studied the effects of protein supplementation and source on milk production, rumen fermentation, N use, and mammary AA utilization. The treatments were unsupplemented control diet, and isonitrogenously given rapeseed meal (RSM), processed (dehulled, flaked, and heated) fava bean without (TFB) or with rumen-protected (RP) Met (TFB+). All diets consisted of 50% grass silage and 50% cereal-based concentrate including studied protein supplement. The control diet had 15% of crude protein and protein-supplemented diets 18%. Rumen-protected Met in TFB+ corresponded to 15 g/d of Met absorbed in the small intestine. Experimental design was a replicated 4 × 4 Latin square with 3-wk periods. The experiment was conducted using 12 multiparous mid-lactation Nordic Red cows, of which 4 were rumen cannulated. Protein supplementation increased dry matter intake (DMI), and milk (31.9 vs. 30.7 kg/d) and milk component yields. Substituting RSM with TFB or TFB+ decreased DMI and AA intake but increased starch intake. There were no differences in milk yield or composition between RSM diet and TFB diets. Rumen-protected Met did not affect DMI, or milk or milk component yields but increased milk protein concentration in comparison to TFB. There were no differences in rumen fermentation except for increased ammonium-N concentration with the protein-supplemented diets. Nitrogen-use efficiency for milk production was lower for the supplemented diets versus control diet but tended to be greater for TFB and TFB+ versus RSM. Protein supplementation increased plasma essential AA concentration but there were no differences between TFB diets and RSM. Rumen-protected Met clearly increased plasma Met concentration (30.8 vs. 18.2 µmol/L) but did not affect other AA. Absence of differences between RSM and TFB in milk production together with limited effects of RP Met suggest that TFB is a potential alternative protein source for dairy cattle. [ABSTRACT FROM AUTHOR]

Ensilaging is one of the most common feed preservation processes using lactic acid bacteria to stabilize feed and save feed quality. The silage bacterial community is well known but the role of the virome and its relationship with the bacterial community is scarce. In the present study, metagenomics and amplicon sequencing were used to describe the composition of the bacterial and viral community during a 40-day grass silage preservation. During the first two days, we observed a rapid decrease in the pH and a shift in the bacterial and viral composition. The diversity of the dominant virus operational taxonomic units (vOTUs) decreased throughout the preservation. The changes in the bacterial community resembled the predicted putative host of the recovered vOTUs during each sampling time. Only 10% of the total recovered vOTUs clustered with a reference genome. Different antiviral defense mechanisms were found across the recovered metagenome-assembled genomes (MAGs); however, only a history of bacteriophage infection with Lentilactobacillus and Levilactobacillus was observed. In addition, vOTUs harbored potential auxiliary metabolic genes related to carbohydrate metabolism, organic nitrogen, stress tolerance, and transport. Our data suggest that vOTUs are enriched during grass silage preservation, and they could have a role in the establishment of the bacterial community. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the exclusive supply of dwarf or tall elephant grass silages, harvested at 60 days of growth, without wilting or the use of additives, on intake, apparent digestibility, nitrogen balance, rumen parameters, and ingestive behavior of sheep. Eight castrated male crossbred sheep (57.6 ± 5.25 kg body weight), fistulated in the rumen, were distributed in two 4 × 4 Latin squares with four treatments and eight animals per treatment and four periods. The treatments consisted of four elephant grass genotype silages (Mott, Taiwan A-146 2.37, IRI-381, or Elephant B). There was no effect of silages (P > 0.05) on dry matter, neutral detergent fiber, and total digestible nutrient intake. The dwarf-sized elephant grass silages provided higher crude protein intake (P = 0.047) and N intake (P = 0.047), while the IRI-381 genotype silage provided higher non-fibrous carbohydrate intake compared to Mott (P = 0.042), without differing from Taiwan A-146 2.37 and Elephant B silages. There were no differences (P > 0.05) among the digestibility coefficients of the evaluated silages. It was observed that silages produced with Mott and IRI-381 genotypes caused a slight decrease in ruminal pH (P = 0.013), and the propionic acid concentration was higher in the rumen fluid of the animals fed with Mott silage (P = 0.021). Therefore, dwarf or tall elephant grass silages, produced with cut genotypes at 60 days of growth and without the use of additives or wilting process, can be used in sheep feeding. [ABSTRACT FROM AUTHOR]

The objective of the trials was to determine the effect of two silage inoculant strains Lactobacillus buchneri and Propionibacteria acidipropionici on grass containing medium and high levels of WSC for fermentation characteristics and aerobic stability of silages. The basic raw materials originated from second growth cut grasses from 2 different plots of the farm: 1st.grass components were a mixture of grass- and leguminous species, contained medium 1.5-3.0% WSC/FM. The 2nd grass components was mainly grass species; with high>3% WSC/FM content. We stored the filled micro (4.2 litre) containers on ambient temperature. It was proven that both inoculant strains significantly decreased lactic acid content (P240 hours was the Lactobacillus buchneri treated silages originated from medium WSC/FM grass. The main advantage of treatment of L. buchneri on grass compared to P. acidipropionici is the longer aerobic stability of silage (P

Maintenance of urban green infrastructure generates a large amount of biomass that can be considered a valuable feedstock for biogas production. This study aims to determine the effect of the cutting time and method of substrate preservation on the specific methane yield (SMY) of urban grass collected from road verges and median strips between roadways in wet (WF) and dry fermentation (DF) technology. The grass was collected three times in a growing season, including in spring, summer, and autumn. The biochemical methane potential (BMP) test was performed on fresh grass, grass ensiled without additives, and grass ensiled with microbiological additives. In addition, the energy potentially produced from biogas and the avoided CO2 emissions were calculated. The highest SMY (274.18 ± 22.59 NL kgVS−1) was observed for the fresh grass collected in spring and subjected to WF. At the same time, the lowest CH4 production (182.63 ± 0.48 NL kgVS−1) was found in the grass ensiled without additives, collected in summer, and digested in DF technology. A comparison of the SMY obtained from the same grass samples in the WF and DF technologies revealed that higher CH4 yields were produced in WF. The electricity and heat production were affected by the time of grass cutting, ensilage method, and AD technology. Generally, less electricity but more heat was produced in DF technology. The least electricity (469–548 kWh tDM−1) was produced from the grass cut in spring and subjected to DF, while the most electricity (621–698 kWh tDM−1) was obtained from the grass collected in autumn and subjected to WF. In the case of heat production, the situation was reversed. The least heat (1.4–1.9 GJ tDM−1) was produced by the grass collected in spring and subjected to WF, while the most heat (2.2–2.7 GJ tDM−1) was produced by the grass collected in autumn and subjected to DF. Ensilage decreased the electricity and heat production in almost all the cuttings. The total reduction in CO2 emissions may amount to 2400 kg CO2 per 1 hectare of road verges. This significant reduction demonstrates that the use of grass from roadside verges in biogas plants should be considered a feasible option. Even though urban grass should be considered a co-substrate only, it can be a valuable feedstock that may partially substitute energy crops and reduce the area needed for energy purposes. Our results reveal that biogas production from the grass waste in WF technology is a stable process. The cutting time and preservation method do not affect the AD process. In DF technology, fresh grass, especially from the late growing season used as feedstock, extends the time of biomass decomposition and, therefore, should be avoided in a real-life biogas plant.

Lignocellulosic biomass is included in the group of renewable energy sources. Its calorific value is high, owing to which it can be successfully used in the production of second-generation fuels, e.g., biogas. However, its complex structure makes it necessary to apply a pretreatment in order to increase the biogas output. This study presents the usability of a pulsed electric field in grass silage pretreatment in methane fermentation and compares it with microwave-induced disintegration. The experiment shows that substrate disintegration with a pulsed electric field (PEF) results in an increase in methane output. The productivity of methane from PEF pretreatment silage increased by 20.1% compared to the untreated control. The application of microwave disintegration, with the assumption that the same energy is used for the pretreatment, resulted in a methane output increase of 6% compared to the control. The highest biogas production output in PEF-pretreated samples was 535.57 NL/kg VS, while the highest biogas output from substrates pretreated with microwaves was 487.18 NL/kg VS. [ABSTRACT FROM AUTHOR]

The synchronous supply of energy and nitrogen (N) substrates to the rumen microbes on grass silage (GS)-based diets can potentially lead to reduced levels of N excreted in the urine. The objective of this study was to evaluate the effect of supplementing GS-based diet with carbohydrate sources differing in rumen fermentation profile on N metabolism of beef heifers. Six Belgian Blue × Holstein Friesian cross beef heifers (487 ± 29 kg BW) were used in a 3 × 3 Latin Square design (n = 6). Dietary treatments were: (RB) GS supplemented with rolled barley; (MM) GS supplemented with maize meal and; (SH) GS supplemented with soya hulls offered at 40:60 forage to concentrate ratio on a dry matter (DM) basis, at maintenance feeding (40 g DM/kg BW0.75). Carbohydrate source had no effect on DM, organic matter, or N intake or total N excretion and the amount of N excreted in the urine (p > 0.05). Animals offered MM excreted a higher percentage of N in the faeces and a lower percentage of N in the urine compared to animals offered RB (p < 0.05). There was a time by interaction for ruminal ammonia (NH3) concentrations (p < 0.01). Ruminal NH3 concentrations peaked at 2 h post-feeding for all treatments. At 3 h post-feeding, ruminal NH3 concentrations for the RB treatment remained higher compared to MM and SH treatments. Molar proportions and total ruminal volatile fatty acids were similar among dietary treatments (p > 0.05). Supplementing GS-based diets with different carbohydrate sources had no impact on the total level of N excreted or the amount of N excreted in the urine. However, there was a higher percentage of N excreted in the faeces and a lower percentage of N excreted in the urine when animals were offered MM compared to those offered RB (p < 0.05). [ABSTRACT FROM AUTHOR]

The research aimed to quantify the occurrence of selected mycotoxins: AFB1 (aflatoxin B1), DON (deoxynivalenol) and ZEN (zearalenone) in maize and grass silages. The silage was prepared in foil bales without the addition of differentiating factors. Silages derived from 36 farms located in Wielkopolskie voivodeship. The total number of mould fungi and the pH value were determined in the collected samples. The level of contamination with selected mycotoxins was determined by high-performance liquid chromatography (HPLC). Based on the obtained results, it was found that the total number of mould fungi in the examined silage samples was in the range 5.00-6.90 log CFU g-1 fresh weight, pH value in the range 3.34-4.73. It was shown that maize silage is more contaminated with mycotoxins than grass silage. In the tested samples, statistically significant differences (P <0.05) were found only for the mycotoxin ZEN. ZEN content was 74% higher in maize silage compared to grass silage. Contamination of silages with mycotoxins AFB1 and DON was at a similar level, and it was 4.22 and 354.14 μg kg-1 for maize and 4.98 and 330.25 μg kg-1 for grasses, respectively. [ABSTRACT FROM AUTHOR]

Pasture-based beef systems can provide cattle slurry and grass silage for anaerobic digestion (AD). However, sustainable production of these feedstocks within a livestock farm presents challenges. This study examined the farmland area required to provide slurry and grass silage for a 40 GWh biomethane plant, quantified greenhouse gas (GHG) emissions reduction and analyzed digestate management. Results indicated that 130 farms of 50 ha and a livestock unit (LU) of 2.1 LU/ha were required to meet the feedstock requirements of the AD plant. Assigning 15 % of the farmland to produce grass silage for AD decreased GHG emissions by 24 % compared to conventional beef farming. Depending on soil nutrient status, returning digestate to the farmland reduced the application of nitrogen, phosphorus and potassium fertilizers by up to 65 %, 33 % and 56 %, respectively. Future research should analyze the economic implication of biomethane production from these feedstocks at farm and supply chain scales. [Display omitted] [ABSTRACT FROM AUTHOR]

Ensilaging is one of the most common feed preservation processes using lactic acid bacteria to stabilize feed and save feed quality. The silage bacterial community is well known but the role of the virome and its relationship with the bacterial community is scarce. In the present study, metagenomics and amplicon sequencing were used to describe the composition of the bacterial and viral community during a 40-day grass silage preservation. During the first two days, we observed a rapid decrease in the pH and a shift in the bacterial and viral composition. The diversity of the dominant virus operational taxonomic units (vOTUs) decreased throughout the preservation. The changes in the bacterial community resembled the predicted putative host of the recovered vOTUs during each sampling time. Only 10% of the total recovered vOTUs clustered with a reference genome. Different antiviral defense mechanisms were found across the recovered metagenome-assembled genomes (MAGs); however, only a history of bacteriophage infection with Lentilactobacillus and Levilactobacillus was observed. In addition, vOTUs harbored potential auxiliary metabolic genes related to carbohydrate metabolism, organic nitrogen, stress tolerance, and transport. Our data suggest that vOTUs are enriched during grass silage preservation, and they could have a role in the establishment of the bacterial community.

This study was conducted to determine if the decreased MP supply predicted by the NRC (2001) when canola meal (CM) substitutes soybean meal (SBM) was supported by direct measurement of net portal absorption of AA or energy-yielding nutrients, plus the impact of the type of forage in CM-based rations. Nine Holstein cows with indwelling catheters in splanchnic blood vessels, 8 also with a ruminal cannula were used to examine the effects of protein source in corn silage-based diets, comparing SBM versus CM, and forage source in CM-based diets, comparing corn versus grass silage. The cows were allocated to a triple 3 × 3 Latin square design with 21-d periods. The 3 experimental diets, formulated to be isoenergetic and isonitrogenous, were based on: 1) SBM and corn silage (SoyCorn); 2) CM and corn silage (CanCorn) and 3) CM and cool-season grass silage (CanGrass). Averages of intake, milk yield and milk composition of the last 3 d of each period were used for statistical analyses. On d 21 of each period, 6 sets of arterial, portal, hepatic and mammary blood samples and 2 ruminal fluid samples were collected. On d 12 of period 2, the protein sources were incubated in nylon bags to determine 16h-ruminal disappearance of DM and N and to obtain 16-h residues. Finally, 5 d after the completion of the Latin square design, the mobile bag technique was used to determine DM and N intestinal disappearance of the 16-h residues of SBM and CM. Pre-planned contrasts were used to compare the effect of the protein source in cows fed corn silage, i.e., SoyCorn versus CanCorn, and the effect of forage in cows fed CM, i.e., CanCorn versus CanGrass. Data of the cow without a rumen canula could not be used because of health problem. In corn silage-based diets, substitution of SBM by CM tended to increase milk (6%) and milk fat (7%) yields. The 8% higher ruminal N disappearance and the 19% decreased MP supply from RUP predicted by NRC (2001) were not supported by the 25% decrease in ruminal ammonia concentration, similar net portal absorption of AA (except 22% higher for Met), and the 14% decrease in urea hepatic removal when CM substituted SBM. Ruminal incubation of CM in nylon bags does not appear suitable for adequate determination of the rumen by-pass of a protein source like CM. Inclusion of grass silage rather than corn silage in CM-based diets tended to increase milk (6%) and increased milk lactose (8%) yields. Neither protein nor forage source resulted in variations of metabolism of energy-yielding nutrients that could explain observed increments in cow performance. The present study indicates no decreased AA availability when CM substitutes SBM. Therefore, substitution of SBM by CM in diets based on corn silage and CM in corn- or grass silage-diets can be used successfully in high producing dairy cows., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Four rod-shaped, non-motile, non-spore-forming, facultative anaerobic, Gram-stain-positive lactic acid bacteria, designated as EB0058 T , SCR0080, LD0937 T and SCR0063 T , were isolated from different corn and grass silage samples. The isolated strains were characterized using a polyphasic approach and EB0058 T and SCR0080 were identified as Lacticaseibacillus zeae by 16S rRNA gene sequence analysis. Based on whole-genome sequence-based characterization, EB0058 T and SCR0080 were separated into a distinct clade from Lacticaseibacillus zeae DSM 20178 T , together with CECT9104 and UD2202, whose genomic sequences are available from NCBI GenBank. The average nucleotide identity (ANI) values within the new subgroup are 99.9 % and the digital DNA-DNA hybridization (dDDH) values are 99.3-99.9 %, respectively. In contrast, comparison of the new subgroup with publicly available genomic sequences of L. zeae strains, including the type strain DSM 20178 T , revealed dDDH values of 70.2-72.5 % and ANI values of 96.2-96.6 %. Based on their chemotaxonomic, phenotypic and phylogenetic characteristics, EB0058 T and SCR0080 represent a new subspecies of L. zeae . The name Lacticaseibacillus zeae subsp. silagei subsp. nov. is proposed with the type strain EB0058 T (=DSM 116376 T =NCIMB 15474 T ). According to the results of 16S rRNA gene sequencing, LD0937 T and SCR0063 T are members of the Lacticaseibacillus group. The dDDH value between the isolates LD0937 T and SCR0063 T was 67.6 %, which is below the species threshold of 70 %, clearly showing that these two isolates belong to different species. For both strains, whole genome-sequencing revealed that the closest relatives within the Lacticaseibacillus group were Lacticaseibacillus huelsenbergensis DSM 11542 5 (dDDH 66.5 and 65.9 %) and Lacticaseibacillus casei DSM 20011 T (dDDH 64.1 and 64.9 %). Based on the genomic, chemotaxonomic and morphological data obtained in this study, two novel species, Lacticaseibacillus parahuelsenbergensis sp. nov. and Lacticaseibacillus styriensis sp. nov. are proposed and the type strains are LD0937 T (=DSM 116105 T =NCIMB 15471 T ) and SCR0063 T (=DSM 116297 T =NCIMB 15473 T ), respectively.

The objective of this study was to evaluate the effects of harvest date in the first regrowth cycle and grass species on intake, in vivo digestibility and its relation to protein utilization in wethers fed timothy or tall fescue silages. Timothy and tall fescue were harvested at regular (RTI and RTF, respectively) or late date (LTI and LTF, respectively) in the first regrowth, creating four experimental silages. Eight wethers were used in a duplicated 4 × 4 Latin square. Experimental periods lasted for 4 wk and wethers were fed ad libitum during the first 3 wk, with intake recorded during the third week. During the fourth week, wethers were fed 80% of ad libitum, and feces and urine were collected during the last 4 d. Wethers receiving RTI showed the greatest DM intake when expressed as kg/d or as percentage of body weight (BW) (P ≤0.05). The intake of neutral detergent fiber (aNDFom) was affected by forage species only, where animals fed timothy silages had greater aNDFom intake than animals fed tall fescue silages (P <0.001). Intakes of CP and sum of the protein fractions A, B 1 and B 2 (AB 1 B 2) were affected by the interaction between harvest date and forage species, where wethers fed RTI showed the greatest intakes of CP (P =0.001) and AB 1 B 2 (P =0.02). Harvesting the forages at late date decreased the in vivo digestibility in wethers but only for timothy, where animals fed LTI silage showed the lowest DM (P <0.001), organic matter (OM) (P <0.001), aNDFom (P =0.02) and acid detergent fiber (P =0.004) digestibility, and a tendency for lower CP digestibility (P =0.07) compared with the other silages. Wethers fed RTI silage showed greater intake of nitrogen (N) (P =0.001) and digestible OM (P =0.003), greater allantoin (P =0.03) and hippuric acid (P =0.05) excretions, greater microbial N flow (P =0.03), and a tendency for greater excretion of fecal N (P =0.09) compared with the other silage-fed animals. In conclusion, delayed harvest decreased in vivo digestibility only in timothy, but even with lower in vivo digestibility wethers fed timothy silages showed a greater intake than wethers fed tall fescue silages, likely due to lower concentration of hydroxycinnamic acids observed in timothy compared with tall fescue as published previously. • Wethers fed timothy harvested at regular date showed the greatest dry matter intake. • Late harvest date decreased in vivo digestibility in wethers only for timothy. • Tall fescue was not affected by maturity stage, showing a wider harvest window. • Wethers fed timothy harvested at regular date showed the greatest nitrogen intake. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is included in the group of renewable energy sources. Its calorific value is high, owing to which it can be successfully used in the production of second-generation fuels, e.g., biogas. However, its complex structure makes it necessary to apply a pretreatment in order to increase the biogas output. This study presents the usability of a pulsed electric field in grass silage pretreatment in methane fermentation and compares it with microwave-induced disintegration. The experiment shows that substrate disintegration with a pulsed electric field (PEF) results in an increase in methane output. The productivity of methane from PEF pretreatment silage increased by 20.1% compared to the untreated control. The application of microwave disintegration, with the assumption that the same energy is used for the pretreatment, resulted in a methane output increase of 6% compared to the control. The highest biogas production output in PEF-pretreated samples was 535.57 NL/kg VS, while the highest biogas output from substrates pretreated with microwaves was 487.18 NL/kg VS.

• Production responses to supplementary protein were not related to forage type. • Production responses were not related to animal variables during covariate period. • Responses to supplementary protein were positively related to intake responses. • Metabolizable protein supply per unit of intake increases with intake. • High yielding cows may not need higher dietary protein concentration. The objectives of the present experiment were to investigate the effects of forage type and protein supplementation on feed intake and milk production, and between-cow variability in responses to protein supplementation. The experiment was conducted using 40 cows (28 Holstein, 12 Nordic Red, 25 multiparous, 15 primiparous). Experiment started with a covariate period of 14 d when cows received TMR (concentrate:forage, 40:60). After the covariate period four experimental diets were arranged in 2 × 2 factorial design with two forages and two concentrate CP levels. The forage treatment included grass silage (GS) and a mixture of whole-crop wheat/oats silage and grass silage (MIX; 40:60) on DM basis. The concentrate treatment included two concentrate CP levels [low CP (115 g CP/kg DM) and medium CP (166 g CP/kg DM)]. Concentrate CP concentration was increased by replacing barley and oats with rapeseed meal. The cows were fed the same forage throughout the 63-d experiment, whereas the CP treatments were compared in a switch-back design including three 21 d periods. Individual protein supplementation response was calculated based on switch-back periods. Feeding the MIX forage increased total DM intake by 1.3 kg/d compared with the GS diets but milk production was not influenced by forage type. Dry matter and nutrient intake increased with CP level similarly with forages. The production of milk components and milk urea concentration increased with CP level, whereas milk N efficiency decreased. Energy corrected milk (ECM) yield response to protein supplementation was not related to ECM yield measured during the covariate period whereas the ECM response was negatively related to calculated energy balance during covariate period. It is concluded that intake and production responses to moderate level of protein supplementation were highly variable, but the extent of variation could not be predicted from animal characteristics available in farm conditions. When the supply of metabolizable protein (MP) was simulated by the Karoline model for each animal, predicted MP concentration increased 0.8 g/kg increase in DM intake. This is compatible to increased MP requirement on DM basis with enhanced production level. Both the lack of the effects of initial production level on CP response and the higher predicted MP concentration with increased intake suggest that high yielding cows can deal with the higher MP requirement (on DM basis) without increasing dietary CP concentration. [ABSTRACT FROM AUTHOR]

The search for sustainable low-carbon energies is on the rise in recent years due to erratic supplies and increasing prices and environmental impacts of widely utilised fossil fuels. Feasibility of cattle slurry-grass silage based biomethane (CSGSB) production as replacement for fossil natural gas is proven. However, high capital and feedstock mobilisation challenges impede national level CSGSB applications, hence the need to consider decentralised CSGSBs (DCSGSBs). The unknown techno-economic potentials of such DCSGSBs under the present economic conditions could however deter investors, thus were assessed using year 2022 bioresource and economic contexts of the rural districts of county Tipperary in Ireland as case study. First principle calculations were applied to simulate available cattle slurry and grass silage biomethane potentials, which were applied to evaluate the economics. Achieved DCSGSB plant capacities were 47.5–105 kt/a. Fixing biomethane price at the average natural gas price (€ 124.6/MWh) resulted in viable DCSGSBs. Profitability of plants ≤47.5 kt/a require grass silage prices ≤14 €/t, while plants ≥71.25 kt/a were viable even under harsh economic conditions (e.g. grass silage at 35–56 €/t). Hence, the DCSGSB is a viable alternative to natural gas for near-term applications, which when implemented could contribute to sustainable energy supplies and low-carbon economies. [Display omitted] • Decentralised cattle slurry/grass biomethane systems analyzed for county Tipperary. • Available cattle/grass resources can yield biomethane ample for total gas demands. • Applicable plant sizes range between 47.5 kt/a and 105 kt/a. • Plants ≤48 kt/a & ≥ 71 kt/a are economical at biomass prices ≤14 €/t & 14–56 €/t. • Levelised cost of energy ranges 84.5–145 €/MWh depending on the plant size. [ABSTRACT FROM AUTHOR]

On-farm anaerobic digestion plants served by virtual biomethane pipelines may be used in areas with no gas grid infrastructure access to improve manure (slurry) management and to produce and deliver renewable gas. A modelling analysis of a simulated virtual biomethane pipeline is presented whereby gas is collected from 100 on-farm biogas plants fed with slurry and grass silage feedstocks and delivered to a market entry point (depot). In total, 7 scenarios are presented in the analysis. In scenarios 1–4, the biogas is upgraded on-site by the digester operator, the biomethane is collected by the haulage vehicle(s) and transported to a single depot. The impact of an additional depot on vehicle routing is investigated in scenarios 5 and 6. Scenario 7 investigates the use of a mobile-upgrading and compression unit, which would allow biogas plant operators to forego the installation and operation of biogas upgrading facilities. In scenario 3 (which considers the largest capacity biomethane haulage vehicles and a single delivery depot) all 100 anaerobic digestion plants are visited over the course of one week using 4 routes, with a total aggregated distance travelled of 205 km. Scenario 7 requires a total routing distance in excess of 613 km to visit all 100 biogas plants and requires long routing times and periods of downtime at each site due to the slow upgrading speed of the mobile unit. The weekly greenhouse gas emissions due to vehicle routing from each scenario are calculated. Assuming diesel-fuelled haulage vehicles, scenario 7 routing results in 431 kg CO 2-eq week−1, a 167% increase in vehicle route emissions compared to scenario 3 (161 kg CO 2-eq week−1). Additionally, whilst the mobile-upgrading unit may alleviate financial challenges, they carry significant logistical challenges, and their resultant higher routing emissions will impact the sustainability of the collected biomethane. Biomethane fuelled haulage vehicles may address this concern if the biomethane is sustainably sourced. • Use of large biomethane haulage vehicles allows for shorter overall distance. • Mobile-upgrading units spend an average of 6 h upgrading biogas from on-farm AD. • Mobile-upgrading units spend 17 h week−1 upgrading biogas from 60 kW e digester. • Total routing distance may significantly influence biomethane sustainability. [ABSTRACT FROM AUTHOR]

• Production of 270 g kg−1 VS VFA. • Successful suppression of methane formation. • Achieving a uniform leachate quality. In a two-stage CSTR system, the anaerobic digestion effluent from the second stage (methane reactor) can be used for pH-control in the acidification reactor. But using batch leach bed reactors, controlling the pH-value is key affecting factor due to dynamic process conditions. The aim of this work was to study, an automatized technical-scale leach bed reactor system for VFA-production with pH-dependent flushing. It was developed and tested at mesophilic and thermophilic operating conditions and compared to a time-controlled flushing mode. The reactors were fed with grass silage and the experiments were run for 35 days. Total cumulative VFA yields up to 270 g kg-1 VS were achieved and extracted from the reactor. The methane formation in the leach bed reactors was successfully suppressed with a pH-controlled flushing mode. As a result of the extraction of the VFA from the leach bed reactors, the methane potential decreased by up to 50 %. [ABSTRACT FROM AUTHOR]

Replacing imported soybean meal (SBM) by domestic protein sources such as grain legumes, food industry by-products or novel resource-efficient feeds is a current research focus to enhance the sustainability of ruminant production systems. In addition, grass silage replacing maize silage can contribute to dietary crude protein (CP) supply as well and complies with the natural diet of ruminants. An experiment with 30 Limousin-sired beef bulls was performed with diets in which SBM was replaced by alternative protein sources when feeding a diet composed of, per kg dry matter (DM), 500 g grass silage, 300 g maize silage and 200 g concentrate. In the concentrate, SBM (control diet) was replaced by faba beans, pumpkin seed cake, or spirulina (Arthrospira platensis) to result on average in 226 g CP/kg concentrate dry matter (DM). A fifth group served as negative control, which received a grain-based concentrate with only 135 g CP/kg DM. Bulls were fed the experimental diets for the entire fattening period starting from an initial body weight (BW) of 164 ± 2.3 kg and 4.3 ± 0.06 months of age. At an average body weight (BW) of 275 ± 5.6 kg and 7.4 ± 0.17 months of age, each animal underwent a 9-day sampling period to determine individual N and energy intake and excretion (7 days of urine and faeces collection) as well as methane emission (2 days in respiration chambers). The diet had no effect on DM and nutrient intake. Apparent fibre digestibility was significantly affected by diet, being numerically lowest with faba beans instead of SBM. Compared to the other groups, the bulls fed no additional protein had the lowest urinary N excretion (25.1 vs. 40.3 g/bull/day; 366 vs. 460 g/kg total faecal and urinary N). Digestive and metabolic energy utilisation were comparable among diets. Methane (CH 4) production adjusted to body weight differed significantly among groups, being numerically highest in bulls fed faba beans (547 vs. 513 mg CH 4 /kg BW/day in the other diets). These results show that none of the tested protein sources, including SBM, was of benefit when feeding a diet containing 500 g/kg DM grass silage complemented with maize silage and concentrate. Feeding such a diet seems to provide an adequate supply with metabolisable protein. Omitting the common protein supplementation therefore mitigated urinary N losses and thus likely N emissions from the manure at unchanged N and energy utilisation. • Response of beef cattle fed a grass-silage based diet to different protein feeds. • Nitrogen (N) and energy use efficiency were comparable among protein sources. • At similar body N retention, utilisation tended to be higher without extra protein. • Urinary N losses were lowest when omitting supplementary protein. • Methane emission was slightly higher when feeding faba beans. [ABSTRACT FROM AUTHOR]

Grass-clover silage constitutes a large part of ruminant diets in Northern and Western Europe, but the impact of silage quality on methane (CH 4) production is largely unknown. This study was conducted to identify the quality attributes of grass silage associated with variation in CH 4 yield. We expected that silage nutrient concentrations and silage fermentation products would affect CH 4 yield, and that these factors could be used to predict the methanogenic potential of the silages. Round bales (n = 78) of grass and grass-clover silage from 37 farms in Norway were sampled, incubated, and screened for in vitro CH 4 yield, i.e. CH 4 production expressed on the basis of incubated organic matter (CH 4 -OM) and digestible OM (CH 4 -dOM) using sheep. Concentration of indigestible neutral detergent fiber (iNDF) was quantified using the in situ technique. The data were subjected to correlation and principal component analyses. Stepwise multiple regression was used to model methanogenic potential of silages. Among all investigated silage composition variables, neutral detergent fiber (aNDFom) and water-soluble carbohydrate (WSC) concentrations obtained the greatest correlations to CH 4 -OM (r = −0.63 and r = 0.57, respectively, P < 0.001), while concentration of iNDF negatively correlated with CH 4 -OM (r = −0.48, P < 0.001). In vivo organic matter digestibility (OMD) and concentration of ammonia-N (NH 3 -N) in silages were also correlated to CH 4 -OM (r = 0.44 and r = −0.32, P < 0.001 and P < 0.01, respectively). The stepwise regression using CH 4 -OM as response variable included aNDFom, WSC, iNDF, silage propionic acid and pH in descending order. The stepwise regression using CH 4 -dOM as response variable included WSC, aNDFom and iNDF in descending order. Among in vitro rumen short chain fatty acids (SCFA), molar proportion of butyrate was the most prominent in increasing CH 4 -OM and CH 4 -dOM (r = 0.23 and r = 0.36, P < 0.05 and P < 0.01, respectively), while molar proportion of propionate was the most prominent SCFA in reducing CH 4 -OM and CH 4 -dOM (r = −0.23 and r = −0.26, respectively, P < 0.05). Regression models that account for silage quality attributes can be used to predict CH 4 yield from silages with a coefficient of determination (R2) between 0.33 (CH 4 -dOM) and 0.65 (CH 4 -OM). In conclusion, concentration of WSC increased in vitro CH 4 -OM and CH 4 -dOM, while concentration of aNDFom and iNDF decreased CH 4 -OM and CH 4 -dOM in grass silages. • Neutral detergent fiber correlated negatively with methane yield. • Concentration of water soluble carbohydrates correlated positively with methane yield. • In vivo organic matter digestibility and methane yield were positively correlated. • Concentration of ammonia-nitrogen was negatively correlated to methane yield. [ABSTRACT FROM AUTHOR]

[Display omitted] • Decentralised biomass is defined as biomass in excess of 15 km from the gas grid. • Over 17% of national on-farm biomass is decentralised but within 15 km of industry. • On-farm biomethane resource is equivalent to 200% of industry gas use in Ireland. • Industry heat demand in two studies can be met by biomethane produced within 2.5 km. A methodology was developed to determine the location and biomethane potential of on-farm biomass feedstocks and furthermore, the quantity of this biomass situated away from an existing gas grid network. The development of decentralised systems which can be integrated with large industry in such locations offers a potential alternative deployment opportunity to centralised gas grid injection. The total biomethane resource from all on-farm feedstocks in a chosen case country (Ireland) was estimated at 67 PJ. Thematic maps were developed to show the quantity of each on-farm feedstock in different regions of Ireland and their distance from the existing gas network. Approximately 17% of the on-farm biomethane resource in Ireland, though in excess of 15 km from the grid, was within a 15 km radius of a large energy user. Two large energy users were presented as case studies, of which their entire heating demand could be met by the on-farm biomethane resource within a 2.5 km radius of each site. Coupling decentralised biomass with large industry users can potentially offer an alternative energy management strategy. [ABSTRACT FROM AUTHOR]