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Binary grass-clover and multi-species swards can increase herbage yields or facilitate reduced inputs of inorganic fertiliser nitrogen (N) compared with perennial ryegrass monocultures. However, the efficiency of the ensilage process and the nutritive value of silage produced from multi-species swards has not been documented. Replicate samples from grass-red clover binary mixture and multi-species mixture swards were ensiled in laboratory silos to assess the ensilability, fermentation characteristics, conservation losses and silage nutritive value compared with grass monocultures produced using inorganic N fertiliser. The results suggest that assessment of the ensilability and subsequent ensilage characteristics of binary and multi-species mixtures should be based on direct sampling from such mixtures rather than being predicted from values obtained from monocultures of constituent species. Under favourable ensiling conditions, unwilted binary mixtures and multi-species mixtures are satisfactorily preserved as silage, comparable to a perennial ryegrass monoculture receiving inorganic N fertiliser. However, when ensiled under more challenging crop conditions the mixtures exhibited a greater requirement for their preservation to be aided, compared with the perennial ryegrass monoculture. Despite the application of inorganic N reducing the legume content of multi-species mixture swards, it had relatively little effect on herbage ensilability or silage preservation. For all species treatments, silage nutritive values were primarily dependent on the pre-ensiling values, although herbage digestibility values declined during ensilage where the ensilage process was inefficient. The current study suggests that in order to be satisfactorily preserved as silage, binary grass-clover and multi-species swards have a greater requirement for an adequate rapid field wilt and/or effective preservative application compared with perennial ryegrass produced using inorganic fertiliser N.

Binary- and multi-species sown mixtures may increase herbage yield and/or reduce inorganic nitrogen (N) requirement compared to perennial ryegrass (PRG) (Lolium perenne L.) swards. A split-plot design was used to compare yields of binary- and multi-species mixtures to single-species swards of three grasses and red clover managed for intensive silage production under varying N application rates. Perennial and Italian (Lolium multiflorum Lam.) ryegrasses had greater annual yields when grown as single species receiving 360 kg N/ha per year than in binary mixtures with red clover (Trifolium pratense L.) receiving 0 kg N/ha per year, whereas timothy (Phleum pratense L.) produced equally high yields in both situations. When no inorganic N was applied, the annual dry matter yield of Mix 1 (10,738 kg/ha; PRG, timothy, red clover and white clover (Trifolium repens L.) and Mix 2 (11,679 kg/ha; PRG, timothy, red clover, ribwort plantain (Plantago lanceolata L.) and chicory (Cichorium intybus L.)) was greater than that of a PRG sward (PRG/0N; 5,885 kg/ha) and derived more from the contribution of legumes than herbs. This yield advantage of mixtures declined as inorganic N input increased, as did the legume and herb proportions in the multi-species swards. When averaged across rates of inorganic N input, Mix 2 had a greater annual yield than Mix 1 (12,464 vs. 11,893 kg/ha). Mix 2 receiving no inorganic fertiliser N and both Mix 1 and Mix 2 receiving 120 kg N/ha per year matched the annual yield achieved by PRG receiving 360 kg N/ha per year. Our results indicate that the yield performance of binary- and multi-species grassland swards should be measured in situ rather than predicted from single-species swards of constituent species.

18 páginas, 7 tablas, 1 figura., In vitro gas production systems are utilized to screen feed ingredients for inclusion in ruminant diets. However, not all in vitro systems are set up to measure methane CH production, nor do all publications report in vitro CH Therefore, the objective of this study was to develop models to predict in vitro CH production from total gas and volatile fatty acid (VFA) production data and to identify the major drivers of CH production in these systems. Meta-analysis and machine learning (ML) methodologies were applied to a database of 354 data points from 11 studies to predict CH production from total gas production, apparent DM digestibility (DMD), final pH, feed type (forage or concentrate), and acetate, propionate, butyrate and valerate production. Model evaluation was performed on an internal dataset of 107 data points. Meta-analysis results indicate that equations containing DMD, total VFA production, propionate, feed type and valerate resulted in best predictability of CH on the internal evaluation dataset. The ML models far exceeded the predictability achieved using meta-analysis, but further evaluation on an external database would be required to assess generalization ability on unrelated data. Between the ML methodologies assessed, artificial neural networks and support vector regression resulted in very similar predictability, but differed in fitting, as assessed by behaviour analysis. The models developed can be utilized to estimate CH emissions in vitro., The in vitro digestion study research was funded by the National Development Plan through the Research Stimulus Fund administered by the Department of Agriculture, Fisheries and Food, Ireland, grant number RSF 05 224, RSF 06 361 and RSF 07 517.

The nutritive value of sown binary- and multi-species grassland mixtures may differ from the values expected based on single-species swards of their constituent species. Field plots were established in a split-plot design to assess the nutritive value of binary- and multi-species mixtures compared to single-species swards of three grass species and red clover (RC) (Trifolium pratense L.) managed for intensive silage production. The nutritive value of grass–legume binary mixtures reflected the values of the constituent species grown on their own, and thus may be predicted from monoculture values. The relatively low digestibility (dry matter digestibility [DMD]) and crude protein (CP) content of the Italian ryegrass (Lolium multiflorum L.) sward compared to perennial ryegrass (Lolium perenne L.) and timothy (Phleum pratense L.) suggests that it may have a limited role in binary- or multi-species swards. Herbage nutritive value in the multi-species swards (Mix 1: perennial ryegrass, timothy, RC and white clover [Trifolium repens L.]; Mix 2: perennial ryegrass, timothy, RC, ribwort plantain [Plantago lanceolata L.] and chicory [Cichorium intybus L.]) appeared to be influenced more by the presence of legumes than herbs. Compared to perennial ryegrass, the multi-species swards had a slower rate of DMD decline prior to Cut 1, but subsequently had lower DMD values at the mid-season harvests. Both multi-species mixtures exhibited DMD, water-soluble carbohydrate (WSC) and CP values that would not have been predicted from their constituent species and thus need to be measured on herbage from field plots growing these mixtures.

Co-digestion of forage silage with cattle slurry can greatly extend the stability of methanogenesis as compared to mono-digestion of the silage. Biogas and methane yields of the mixtures of perennial ryegrass silage (grass harvested at two growth stages i.e. stem elongation vs. floral development) with cattle slurry and of red clover silage (clover harvested at two growth stages i.e. mid-vegetative vs. early seed-pod development) with cattle slurry were measured, and synergistic effects were investigated. Silage and slurry were incubated as sole substrates or as part of binary mixtures (forage silage:cattle slurry ratios of 1:0, 0.75:0.25, 0.5:0.5, 0.25:0.75 and 0:1 on a volatile solid basis). The maximum measured synergistic effects for perennial ryegrass silages with cattle slurry and red clover silages with cattle slurry were observed at 0.75:0.25 and 0.5:0.5 (forage silge:cattle slurry), respectively. The forage silage:cattle slurry ratio to produce the maximum synergistic effects differed with the forage species ensiled and its growth stage when harvested.

Anaerobic co-digestion of contrasting substrates can result in synergistic or antagonistic effects on methanogenesis. Biogas and methane yields of the mixtures of cattle slurry (CS1 and CS2) or pig slurry with grass silages (GS1 and GS2) were measured using in vitro anaerobic batch digesters, and synergistic and antagonistic effects were investigated. Slurries and silages were incubated as individual substrates or as part of binary mixtures (slurry:silage mass ratios of volatile solids (VS) of 1:0, 0.75:0.25, 0.5:0.5, 0.75:0.25 and 0:1). The biogas yields of CS1, CS2, pig slurry, GS1 and GS2 were 405.9, 380.4, 550.8, 673.7 and 610.6 L kg−1 of VS, respectively while the corresponding methane yields were 269.1, 246.4, 380.1, 427.7 and 359.0 L kg−1 of VS. The sequential replacement of either cattle slurry by either grass silage caused a progressive increase in biogas and methane yields, but there was not as clear-cut increase when pig slurry was replaced by grass silages. The methane yield for slurry and silage mixtures displayed non-linear blending and the maximum effect, which was always antagonistic, was at a 0.5:0.5 mass ratio of VS, and ranged from 5.7-7.6 % below the yields predicted from mono-digestion of individual substrates.

The aims were to quantify the effects of applying fibrolytic enzymes at ensiling on conservation characteristics and specific methane (CH4) yields (SMY) per unit mass, and per unit land area. At two stages of primary growth, four replicate plots of two species (perennial ryegrass and timothy) were subjected to nine treatments, an untreated control and four fibrolytic enzymes (ENZ 1–4) applied at two enzyme dosage rates (low and high) prior to ensiling. Silage SMYs were subsequently determined in an in vitro batch anaerobic digestion test. Generally, applying fibrolytic enzymes at ensiling reduced total fibre compared to control silages, which consequently enhanced mass-SMY and area-SMY. However, the impact on fibre, mass-SMY and area-SMY differed depending on both grass species and growth stage at harvest, with no single enzyme being consistently superior. Thus the potential of enhanced methane output with added enzymes at ensiling is both fibrolytic enzyme and grass substrate specific.

Aims Silage is grass, preserved by fermentation and used as winter feed for cattle. The impact of a range of current grass silage preparation practices on the survival of Escherichia coli C600φ3538(Δvtx2 ::cat) and on the induction, release and infectivity of free phage were investigated. Methods and results Wilted and fresh grass samples, from plots with and without slurry application, were ensiled with or without formic acid. Each treatment combination was inoculated with approximately 6 log10 CFU per g E. coli C600φ3538(Δvtx2 ::cat) (donor strain) and E. coli C600::kanamycinR (recipient strain) in test-tube model silos and incubated in the dark at 15°C. The physico-chemical (pH, ammonia, ethanol, lactic acid and volatile fatty acids) and microbiological (total viable counts, TVC, total Enterobacteriaceae counts, TEC, E. coli counts, ECC and lactic acid bacteria, LAB) properties of each fermentation were monitored throughout the experiment as were the concentrations of E. coli C600φ3538(Δvtx2 ::cat), E. coli C600::kanamycinR , free phage and transductants, using culture and PCR-based methods. Over the course of the experiment the pH of the grass samples typically decreased by 2 pH units. TVC, TEC and ECC decreased by up to 2·3, 6·4 and 6·2 log10 CFU per g, respectively, while the LAB counts remained relatively stable at 5·2-7·1 log10 CFU per g. Both donor and recipient strains decreased by approximately 5 log10 CFU per g. Free phages were detected in all treatments and transductants were detected and confirmed by PCR in the silo containing wilted grass, pretreated with slurry and ensiled without formic acid. Conclusions Verocytotoxigenic E. coli may survive the ensiling process and the conditions encountered are sufficient to induce vtx2 bacteriophage leading to low levels of phage-mediated vtx2 gene transfer. Significance and impact of the study These studies suggest that the ensiling of grass may create an environment which facilitates the emergence of new verocytotoxigenic E. coli.

Beef cattle partition dietary nitrogen (N) into tissues or excrete it in feces and urine, which contributes significantly to water and air pollution. The objectives were to examine the effects of supplementing fresh grass herbage with a low crude-protein, high-energy supplement - citrus pulp - on intake, digestion and N-balance in beef cattle. Sixteen Charolais steers (live weight 585 kg, S.D. 24.1) were used in a randomized block design experiment. Treatments consisted of either unsupplemented zero-grazed grass (predominantly Lolium perenne) harvested 21-d after it received 50 kg N/ha, offered ad libitum (GO), or the same grass supplemented with 2.25 kg citrus pulp DM daily (GS). Following a 21-d dietary adaptation phase, animals were accommodated in metabolism stalls for 10 d (2-d adaptation: 8-d sampling). During this period grass and citrus pulp was offered at 0.85 of the pre-determined daily DM intake; the grass: supplement ratio for GS remained the same as during the adaptation phase. Grass was offered in two equal meals and citrus pulp in one morning meal. Total faeces and urine were collected on a 48-h and 24-h basis, respectively. Data were analysed using AVOVA with terms for treatment and block in the model. Supplementation decreased (P0.05) between treatments. Total N and urinary N excretion were 15 and 23 g/d lower, respectively, and faecal N excretion was 9 g/d greater for GS compared to GO (P0.05). The quantity of N retained and, therefore, N-use efficiency did not differ (P>0.05) between treatments (33 vs. 28 %). Supplementing grass herbage with a low-protein, high-energy feed may be a strategy to reduce total and urinary N excretion in grazing beef cattle.

Many pre- and post-mowing on-farm traits influence mycotoxin occurrence and conventional chemical compositionin grass silages. The objective of this study was to determine if observed on-farm pre- or post-mowing factors can be used to indicate mycotoxin occurrence or conventional chemical composition traits in grass silages. Over a two year period (2012-2013 and 2013-2014) 290 grass silages were sampled on 145 farms and these consisted of baled (n=115) and pit (n=175) silages. On each farm in each year, a questionnaire was completed and pre- and post-mowingfactors recorded. The preservation quality was better in pit compared to baled silages in both years and in silages made in Year 2 compared with Year 1. On-farm pre- and post-mowing factors were generally not secure indicators of silage conventional chemical characteristics. In contrast, the occurrence of enniatins and beauvericin generally increased with harvesting month (May-October) for grass silages. Visible mould on baled grass silages and a rottedtop layer with pit grass silages were associated with andrastin A, mycophenolic acid and roquefortine C occurrence.

This six year experiment quantified the impacts of management factors on red clover yield, persistence, nutritive value and ensilability, and compared these to perennial ryegrass receiving inorganic N fertiliser. Within a randomised complete block design, field plots were used to evaluate a 2 (cultivar; Merviot and Ruttinova) x 2 (alone or with perennial ryegrass) x 2 (0 and 50 kg fertiliser N/ha in mid March) x 2 (harvest schedule) combination of factors relating to red clover, and a 2 (harvest schedule) x 4 (0, 50, 100 and 150 kg N/ha for each cut) combination of factors relating to perennial ryegrass. The Early and Late harvest schedules both involved four cuts per year but commenced a fortnight apart. Red clover treatments averaged 14,906 kg dry matter/ha per year. There was no yield decline evident across years despite a decline in the proportion of red clover. The Early harvest schedule and sowing ryegrass with red clover increased herbage yield and digestibility. March application of fertiliser N to red clover treatments reduced annual yield. Early harvest schedule increased and both fertiliser N and sowing with ryegrass decreased the proportion of red clover. Sowing with ryegrass improved indices of ensilability but reduced crude protein. Both red clover cultivars had similar performance characteristics. A selected red clover-based treatment, considered to exhibit superior overall production characteristics, out-yielded perennial ryegrass plus fertiliser N in mid-season. However, it had poorer digestibility and ensilability indices.

Mycotoxins are heterogeneously distributed analytes such that obtaining a representative sample of silage for analysis can be highly challenging. The objectives of this study were to: (1) identify the variability in mycotoxin concentrations, nutritional value characteristics and fermentation characteristics when 20 cores were taken from individual next-to-be-fed silage bales and five cores were taken from the next-to-be-fed section of the feed face of pit silages, (2) compare the values obtained from intensive sampling of the silage after simulated feed-out to values obtained by the above mentioned core sampling, and (3) describe the impact of reducing the number of core samples taken from the baled and pit silages. Round baled silages (n=10) or sections (2 m wide × 1 m height) of pit silages (n=10) were core sampled at twenty and five positions, respectively. After coring, baled silages were chopped, mixed and placed along a simulated feed trough. Silage in the simulated feed trough was then grab sampled (n=20) to produce an aggregate sample, and this was undertaken in triplicate. For pits, silage was mixed and placed along a simulated feed trough before being sampled, as per baled silage. Variation within or among either baled or pit silages, and for core or feed trough samples, was generally much higher for mycotoxins than for conventional chemical composition traits. Within silage (bale or pit) and among silages, variation was generally reduced when samples were collected from the feed trough, except for mycotoxins in pit silages which had higher variation in the feed trough compared with core samples. Increasing the number of core samples increased the likelihood of detecting a positive sample if present and precise estimates of the true chemical composition of the population. Representatively sampling a next-to-be-fed section or bale of silage for conventional chemical characteristics was achieved with 2-4 core samples or 1-2 feed trough samples. However, in contrast, when sampling silages for mycotoxins, collecting a representative sample using core or feed trough sampling methods sometimes required over 100 and over 20 samples, respectively.

High lignocellulose content grass silage was investigated for two-phase digestion (leaching followed by upflow anaerobic sludge blanket (UASB)) for application to demand-driven biogas production. Leaching trials were undertaken investigating the effects of particle size reduction and rumen fluid addition on the hydrolysis and acidogenesis phases. Reducing grass silage particle size to 3 cm particle size. Rumen fluid addition increased production of volatile fatty acids (VFA) but reduced pH levels, which subsequently hindered hydrolysis of volatile solids (VS). When electricity demand is low, it is recommended to operate in leach only mode with grass silage particle size >3 cm and with rumen fluid addition; this limits VS destruction to 30% while maintaining a high VFA yield. When electricity demand is high, connection of the UASB generates 61% destruction of VS maximising biogas production. Operation of the SLBR-UASB achieves lower specific methane yields than traditional single-stage digestion but may offer advantages in demand driven biogas systems.

Recent studies of baled silages produced in Ireland have identified considerable filamentous fungal contamination. Many of these fungi are toxigenic, capable of producing secondary metabolites, namely mycotoxins. Mycotoxins are potentially detrimental to livestock health and some can pose a risk to consumers of animal products. Baled (n=20) and pit (n=18) silages from a sample of farms (n=38) in Co. Meath were examined to assess the occurrence of mycotoxins and ascertain whether sampling position within the pit silos (feed face vs. 3 m behind the feed face) has an effect on mycotoxin content or other chemical compositional variables. Of the 20 mycotoxins assayed, baled silages contained [mean of positive values (no. of values in mean)] mycotoxin concentrations (μg/kg dry matter) of beauvericin 36 (2), enniatin (enn.) A 9.3 (3), enn. A154 (8), enn. B 351 (9), enn. B1136 (10), mycophenolic acid (MPA) 11,157 (8) and roquefortine C (Roq. C) 1037 (8) and pit silages contained beauvericin 25 (2) enn. A118 (2), enn. B 194 (9), enn. B157 (3), MPA 287 (6), Roq. C 3649 (6) and zearalenone 76 (1). There was no difference (P>0.05) observed in the mycotoxin concentrations between baled and pit silages, and 11 of the 20 mycotoxins assayed were below the limits of detection. The position of sampling had no effect on the mycotoxin concentration detected in pit silages. It is concluded that mycotoxin concentrations detected in these pit and baled silages in Co. Meath did not exceed EU regulation or guidance limits, and that similar chemical composition and mycotoxin concentration values occurred at the pit silage feed face and 3 m behind this feed face.

Enteric methane (CH) production attributable to beef cattle contributes to global greenhouse gas emissions. Reliably estimating this contribution requires extensive CH emission data from beef cattle under different management conditions worldwide. The objectives were to: 1) predict CH production (g d animal), yield [g (kg dry matter intake; DMI)] and intensity [g (kg average daily gain)] using an intercontinental database (data from Europe, North America, Brazil, Australia and South Korea); 2) assess the impact of geographic region, and of higher- and lower-forage diets. Linear models were developed by incrementally adding covariates. A K-fold cross-validation indicated that a CH production equation using only DMI that was fitted to all available data had a root mean square prediction error (RMSPE; % of observed mean) of 31.2%. Subsets containing data with ≥25% and ≤18% dietary forage contents had an RMSPE of 30.8 and 34.2%, with the all-data CH production equation, whereas these errors decreased to 29.3 and 28.4%, respectively, when using CH prediction equations fitted to these subsets. The RMSPE of the ≥25% forage subset further decreased to 24.7% when using multiple regression. Europe- and North America-specific subsets predicted by the best performing ≥25% forage multiple regression equation had RMSPE of 24.5 and 20.4%, whereas these errors were 24.5 and 20.0% with region-specific equations, respectively. The developed equations had less RMSPE than extant equations evaluated for all data (22.5 vs. 23.2%), for higher-forage (21.2 vs. 23.1%), but not for the lower-forage subsets (28.4 vs. 27.9%). Splitting the dataset by forage content did not improve CH yield or intensity predictions. Predicting beef cattle CH production using energy conversion factors, as applied by the Intergovernmental Panel on Climate Change, indicated that adequate forage content-based and region-specific energy conversion factors improve prediction accuracy and are preferred in national or global inventories., Authors gratefully acknowledge project funding from the USDA National Institute of Food and Agriculture Federal Appropriations under Project PEN 04539 and Accession number 1000803; the Joint Programming Initiative on Agriculture, Food Security and Climate Change (FACCE-JPI)’s ‘GLOBAL NETWORK’ project and the ‘Feeding and Nutrition Network’ (http://animalscience.psu.edu/fnn) of the Livestock Research Group within the Global Research Alliance for Agricultural Greenhouse Gases (www.globalresearchalliance.org); the Sesnon Endowed Chair program (UC Davis); the Swiss Federal Office of Agriculture, Berne, Switzerland; AHDB Beef and Lamb, the Scottish Government, Defra and the devolved administrations through the UK Agricultural Greenhouse Gas Inventory Research Platform; French National Research Agency through the FACCE-JPI program (ANR-13-JFAC-0003-01); the Cooperative Research Program for Agriculture Science, (Project No. PJ013448012018), RDA, Republic of Korea; the Australian Government Department of Agriculture, Fisheries and Forestry (Carbon Farming Futures Action on the Ground program; AOTGR2-0400); the financial support of the Reducing Emissions from Livestock Research Program, the National Livestock Methane Program, Meat and Livestock Australia, CSIRO and Ridley AgriProducts Pty, Ltd; the Institute of Science and Technology in Animal Science (INCTCA 465377/2014-9), the Department of Agriculture, Food and the Marine (DAFM), Ireland (AGRI-I project); European Commission through SMEthane (FP7‐SME‐262,270); Beef Cattle Research Council of the Canadian Cattlemen’s Association; the Cofund for Monitoring & Mitigation of Greenhouse Gases from Agri- and Silvi-culture (FACCE ERA-GAS)’s project Capturing Effects of Diet on Emissions from Ruminant Systems and the Dutch Ministry of Agriculture, Nature and Food Quality (AF-EU-18010 & BO-4400159-01).

Under Irish conditions, the digestibility in May of grass managed for silage production is sometimes lower than expected. In each of two successive years, replicate field plots were established to examine the effects of three defoliation heights (uncut or cut to a stubble height of 10 or 5 cm) applied in winter and/or spring on herbage yields harvested in May and again in July, and on chemical composition and conservation characteristics associated with first-cut silage. Swards that were not defoliated in December or March had a dry-matter (DM) yield and in vitro DM digestibility (DMD) in mid-May of 6597 kg ha−1 and 736 g kg−1, respectively, in Year 1, and corresponding values of 7338 kg ha−1 and 771 g kg−1 in Year 2. Defoliating swards to 5 cm in December reduced (P

Effective biogas production from seaweed necessitates harvest at times of peak quality of biomass and low-loss preservation for year-around supply. Ensiling of five seaweed species and storage up to 90 days was investigated as a method to preserve the methane yield potential. Adequate acidification by natural lactic acid fermentation was difficult due to low rapidly fermentable carbohydrate contents, high buffering capacities and low initial numbers of lactic acid bacteria. Nevertheless, products of silage fermentation increased methane yields by up to 28% and compensated for volatile solid losses during ensiling. Preservation of the original methane yield potential was achieved for four of five seaweed species, provided that silage effluent is collected and utilised. 10–28% of the ensiled biomass was released as effluent with methane yields of 218–423 L N kg −1 VS. If further optimised, ensiling represents an effective method of preservation crucial for an efficient seaweed biofuel industry.

SUMMARYGrazing season length (GSL) on grassland farms with ruminant production systems can influence farm economics, livestock disease transmission, environmental impact, milk and meat quality, and consumer choice. Bioclimatic variables are biologically meaningful climate variables that may enable predictions of the impact of future climate change on GSL on European farms. The present study investigated the spatial relationship between current GSL (months) measured by EUROSTAT on dairy, beef and sheep farms in 706, 774 and 878 regions, respectively, and bioclimatic variables. A stepwise multiple regression model revealed a highly significant association between observed GSL and bioclimatic variables across Europe. Mean GSL was positively associated with the mean temperature of the coldest quarter and isothermality, and negatively associated with precipitation in the wettest month. Extrapolating these relationships to future climate change scenarios, most European countries were predicted to have a net increase in GSL with the increase being largest (up to 2·5 months) in the north-east of Europe. However, there were also predictions of increased variability between regions and decreases in GSL of up to 1·5 months in some areas such as the west of France, the south-west of Norway and the west coast of Britain. The study quantified and mapped the potential impact of climate change on GSL for dairy, beef and sheep farms across Europe.

Toxicogenic fungal moulds have been previously identified in Irish farm silages and are known to be capable of producing mycotoxins. Mycotoxins are detrimental to animal health and performance and can be transferred through feed to animal produce. The objectives of this study were to identify and quantify the challenge posed to livestock from mycotoxins in Irish silages and determine whether conventional chemical characteristics could be used as indicators of mycotoxin occurrence. Over the 2-year period, 300 silages were sampled on 150 farms and these consisted of round-baled grass silages (n = 115) and pit silages of either grass (n = 175) or maize (n = 10). There was no significant difference in mycotoxin concentrations across silage types in either year, except for baled silage containing higher concentrations of enniatin B compared with pit silage in Year 1. Conventional chemical characteristics of silages were generally not reliable predictors for mycotoxin incidences; however, dry-matter digestibility, crude protein, fermentation products and ash did predict the incidence of enniatins and beauvericin. The incidence and concentration of the twenty measured mycotoxins were generally low and individual mycotoxin concentrations recorded were considerably lower than current EU directive or guidance thresholds. Non-regulated mycotoxins measured were similar to or lower than concentrations reported in the literature. Based on current knowledge and the concentrations of individual mycotoxins detected in this study, the challenge to Irish livestock and livestock products from animal consuming silage is generally low. However, the additive or synergistic effects of multiple mycotoxins in silage are unknown.

This study examined 169 of the newest varieties of three ryegrass species, perennial (Lolium perenne L.), Italian (Lolium multiflorum Lam.) and hybrid (Lolium boucheanum Kunth), from Recommended List trials in Ireland. The traits examined were yield, dry matter concentration, three nutritive value traits (in vitro dry matter digestibility, water-soluble carbohydrate on a dry matter basis and crude protein concentration) and two ensilability traits (buffering capacity and water soluble carbohydrate concentration on an aqueous phase basis). Varietal monocultures of each species underwent a six cut combined simulated grazing and silage management in each of two years following sowing. Perennial ryegrass yielded less than both other species in one-year-old swards, but less than only Italian ryegrass in two-year-old swards, but generally had the higher in vitro dry matter digestibility and crude protein values. Italian ryegrass displayed the most favourable ensilability characteristics of the three species with perennial ryegrass less favourable and hybrid ryegrass intermediate. Overall, despite the high yields and favourable nutritive value and ensilability traits recorded, the general differences between the three ryegrass species studied were in line with industry expectations. These findings justify assessing the nutritive value and ensilability of ryegrass species, in addition to yield, to allow farmers select species that match farming enterprise requirements.

Fasciolosis caused by Fasciola hepatica is a widespread parasitic disease in cattle farms. The aim of this study was to detect clusters of fasciolosis in dairy cow herds in Munster Province, Ireland and to identify significant climatic and environmental predictors of the exposure risk. In total, 1,292 dairy herds across Munster was sampled in September 2012 providing a single bulk tank milk (BTM) sample. The analysis of samples by an in-house antibody-detection enzyme-linked immunosorbent assay (ELISA), showed that 65% of the dairy herds (n = 842) had been exposed to F. hepatica. Using the Getis-Ord Gi* statistic, 16 high-risk and 24 low-risk (P F. hepatica in the temperate Irish climate. The findings of this study highlight the importance of cluster analysis for identifying significant differences in climatic and environmental variables between high-risk and low-risk clusters of fasciolosis in Irish dairy herds.

Fasciolosis caused by Fasciola hepatica is responsible for major production losses in cattle farms. The objectives of this study were to assess the effect of farm management practices on liver fluke prevalence on Irish dairy farms and to document the current control measures against parasitic diseases. In total, 369 dairy farms throughout Ireland were sampled from October to December 2013, each providing a single bulk tank milk (BTM) sample for liver fluke antibody-detection ELISA testing and completing a questionnaire on their farm management. The analysis of samples showed that cows on 78% (n=288) of dairy farms had been exposed to liver fluke. There was a difference (P0.05) between farms where cows were positive or negative for liver fluke antibodies in (a) the total number of adult dairy cows in herds, (b) the number of adult dairy cows contributing to BTM samples, and (c) the size of the total area of grassland, with positive farms having larger numbers in each case. There was no difference (P0.05) between positive and negative farms in (a) the grazing of dry cows together with replacement cows, (b) whether or not grazed grassland was mowed for conservation, (c) the type of drinking water provision system, (d) spreading of cattle manure on grassland or (e) for grazing season length (GSL; mean=262.5 days). Also, there were differences (P0.001) between drainage statuses for GSL with farms on good drainage having longer GSL than moderately drained farms. The GSL for dairy cows on farms with good drainage was 11 days longer than for those with moderate drainage (P0.001). The percentage of farmers that used an active ingredient during the non-lactating period against liver fluke, gastrointestinal nematodes, lungworm, and rumen fluke was 96%, 85%, 77% and 90%, respectively. Albendazole was the most frequently used active ingredient for treatment against gastrointestinal nematodes (57%), liver fluke (40%) and lungworm (47%), respectively. There was a difference (P0.05) in the use of triclabendazole and albendazole between positive and negative farms, with triclabendazole use being more common in positive farms. This study highlighted differences in dairy management practices between Irish farms with dairy herds exposed or not exposed to liver fluke and stressed the need of fine-scale mapping of the disease patterns even at farm level to increase the accuracy of risk models. Also, comprehensive advice and professional support services to farmers on appropriate farm management practices are very important for an effective anthelmintic control strategy.

This study investigated the feasibility of mono-digesting grass silage, dairy slurry and the co-digestion of the two substrates at a range of concentrations with a specific focus on digester performance while increasing organic loading rate (OLR). The results show that the higher the proportion of grass silage in the substrate mix the higher the specific methane yield (SMY) achieved. Optimum conditions were assessed for 100% grass silage at an OLR of 3.5 kg VS m(-3) d(-1) generating a SMY of 398 L CH4 kg(-1) VS equating to a biomethane efficiency of 1.0. For co-digestion of grass silage with 20% dairy slurry the optimum condition was noted at an OLR of 4.0 kg VS m(-3) d(-1) generating a SMY of 349L CH4 kg(-1) VS and a biomethane efficiency of 1.01. Hydraulic retention times of less than 20 days proved to be a limiting factor in the operation of farm digesters.

As a plant group, forage legumes present some unique advantages and disadvantages for ruminant production. When compared to grasses or cereals their main advantages are generally (i) low reliance on fertilizer nitrogen (N) inputs, (ii) high voluntary intake and animal production when feed supply is non-limiting and (iii) high protein content. The main disadvantages of forage legumes are generally (i) lower persistence than grass under grazing, (ii) high risk of livestock bloat and (iii) difficulty to conserve as silage or hay. In comparison to grass or legume monocultures, grass + legume mixtures have particular advantages such as more balanced feeding values, increased resource use efficiency and increased herbage production. However, maintaining the optimum legume contents (40-60% of herbage dry matter) to achieve these benefits remains a major challenge on farms. When compared to ruminant systems based on grass or cereals supplemented with fertilizer N, forage legume based ruminant systems tend to have...

Dried milled biomass samples are frequently utilised in small-scale batch digestion tests. However, herbage chemical composition can be altered by thermal drying, and this may affect specific methane (CH4) yields. Thus, the specific CH4 yield of herbage pre- and post-ensiling, prepared by two preparation methods were compared. Perennial ryegrass samples were either non-thermally dried (i.e. subject to cryogenic conditions, −196 °C) or thermally dried (40 °C), prior to milling. Specific CH4 yield was subsequently determined in a small-scale batch digestion test. Herbage pre-ensiling yielded 204 and 243 L CH4 kg−1 VSadded and herbage post-ensiling yielded 212 and 188 L CH4 kg−1 VSadded with non-thermal dried and thermal dried sample preparation methods, respectively. Due to opposing effects of thermal drying on CH4 yields of herbage either pre- or post-ensiling, it is not recommended to use thermal drying. Instead, it is recommended that non-thermal dried herbage samples are used in small-scale batch digestion tests.

Grassland biomass is likely to be harvested and stored as silage to ensure a predictable quality and a constant supply of feedstock to an anaerobic digestion facility. Grass ( Phleum pratense L. var. Erecta) was ensiled following the application of one of six contrasting additive treatments or a 6 h wilt treatment to investigate the effects of contrasting silage fermentation characteristics on CH 4 yield. In general, silage fermentation characteristics had relatively little effect on specific CH 4 yield (from 344 to 383 Nl CH 4 kg −1 volatile solids). However, the high concentrations of fermentation products such as ethanol and butyric acid following clostridial and heterofermentative lactic acid bacterial fermentations resulted in a numerically higher specific CH 4 yield. While the latter fermentation products of undesirable microbial activity have the potential to enhance specific CH 4 yield, the numerically higher specific CH 4 yield may not compensate for the associated total solids and energy losses during ensiling.

peer-reviewed The effects of two fertiliser nitrogen (N) application rates - 15 (LN) or 80 (HN) kg N/ha - to Lolium perenne dominant swards in spring, on grass dry matter (DM) intake, digestion, rumen fermentation, microbial N production and N-balance in beef cattle, and in vitro fermentation and methane production were studied. Sixteen Charolais steers with a mean live weight (s.d.) of 475 (18.4) kg, were used in a completely randomised block design experiment and offered zero-grazed grass harvested 21-d post N application. The same grass was incubated in an eight-vessel RUSITEC in a completely randomised block design experiment. The HN treatment had a 540 kg/ha higher grass DM yield, and a 20 g/kg DM higher crude protein (CP) concentration compared to LN. There was no difference (P > 0.05) in DM intake, or in vivo DM, organic matter (OM) and N digestibility between treatments. Rumen fermentation variables pH, lactic acid, ammonia (NH3) and total volatile fatty acid (VFA) concentration were similar (P > 0.05) for both treatments. Nitrogen intake was 19 g/d higher (P 0.05) between treatments. The quantity of N retained and N-use efficiency did not differ (P > 0.05) between LN and HN. Plasma urea concentration was 1 mmol/L greater (P 0.05) between HN and LN. In vitro methane and total gas output were not different (P > 0.05) between treatments. Reducing fertiliser N application rate to grass in spring reduced total and urinary N excretion, which has environmental benefits, with no effects on in vitro methane output. The author (Alan O’Connor) was in receipt of a Teagasc Walsh Fellowship, and financial support was provided by the Department of Agriculture, Food and the Marine Research Stimulus Programme (Excess N, 11/S/105).

Nitrogen (N) excretion from cattle contributes to water and air pollution. The objective was to determine the effects of inorganic fertiliser N application rate to mid-season grass (July-August) on herbage chemical composition, and intake, digestion and N-balance in beef cattle. Sixteen Charolais steers (live weight 568 kg, S.D. 22.1) were used in a randomised block design experiment. Treatments were zero-grazed grass herbage (predominantly Lolium perenne) harvested 21 d after receiving either 15 (LN) or 80 (HN) kg N/ha. Herbage was offered ad-libitum daily and dry matter (DM) intake measured during a 12-d diet adaptation phase and at 0.9 of this DM intake during the subsequent 10-d period in metabolism stalls. Total faeces and urine were collected on a 48-h and 24-h basis, respectively, for 8 d. Blood samples were obtained by jugular venepuncture immediately before, and 3 and 6 h post-feeding on d 12 and 22; plasma urea concentrations for the six sampling times were averaged giving one value per treatment. Data were analysed using AVOVA with terms for treatment and block in the model. Herbage DM concentration was 138 vs. 149 g/kg, and crude protein concentration was 206 vs. 156 g/kg DM, respectively, for HN and LN. Herbage DM intake (7.8 kg/d) and in vivo DM digestibility (816 g/kg) did not differ (P>0.05) between treatments. Compared to LN, N intake, N digestibility and faecal N loss was 75 g/d, 34 g/kg and 5 g/d greater, respectively, for HN (P

Summary Maize stover (total stem and leaves) is not considered a ruminant feed of high nutritive value. Therefore, an improvement in its digestibility may increase the viability of total forage maize production systems in marginal growth regions. The objective of this study was to describe the changes in chemical composition during the storage of contrasting components of maize stover (leaf, upper stem and lower stem) treated with either of two lignin degrading white-rot fungi (WRF; Pleurotus ostreatus, Trametes versicolor). Three components of maize stover (leaf, upper stem and lower stem), harvested at a conventional maturity for silage production, were digested with either of two WRF for one of four digestion durations (1–4 months). Samples taken prior to fungal inoculation were used to benchmark the changes that occurred. The degradation of acid detergent lignin was observed in all sample types digested with P. ostreatus; however, the loss of digestible substrate in all samples inoculated with P. ostreatus was high, and therefore, P. ostreatus-digested samples had a lower dry matter digestibility than samples prior to inoculation. Similarly, T. veriscolor-digested leaf underwent a non-selective degradation of the rumen-digestible components of fibre. The changes in chemical composition of leaf, upper stem and lower stem digested with either P. ostreatus or T. veriscolor were not beneficial to the feed value of the forage, and incurred high DM losses.

The fibre-rich press-cake fraction produced by ‘green biorefineries’ may provide a sustainable solution for the control of restrained drying shrinkage cracking in stabilised soil blocks and cementitious mortars. Following determination of the tensile strength of selected grass species at different harvest dates, the effect of press-cake inclusion was assessed in controlling the shrinkage of clay and mortar specimens. The press-cake was found to be effective in controlling the onset of early-restrained drying shrinkage cracking in both clay and cementitious specimens. The addition of press-cake fraction to terracotta pottery clay had a pronounced beneficial effect on early-restrained shrinkage, increasing the time to first crack by over 5 h and reducing the crack width by 4.9 mm relative to the control. Inclusion of the press-cake fraction in mortar specimens (at a rate of 2.2 kg m −3 ) eliminated crack formation completely, compared with the unreinforced mortar specimens which cracked after 3 h. This positive influence on the consequences of restrained shrinkage occurred despite the fact that early-age free shrinkage rates were found to increase in proportion to press-cake inclusion rate. Furthermore, in cementitious specimens the performance of the press-cake compared well with polypropylene fibres in respect of mitigating the risk of cracking due to early-age restrained shrinkage in cementitious specimens.

In a Green Biorefinery processing green biomass one possible application for the press-cake fraction is as a feedstuff for ruminants. This study investigates the effects of ensiling and fractionation on the estimated nutritive value of three grassland species harvested at different stages of maturity. Perennial ryegrass (Lolium perenne L., var. Gandalf), cocksfoot (Dactylis glomerata L., var. Pizza) and red clover (Trifolium pratense L., var. Merviot) were grown in field plots and harvested and ensiled in laboratory silos. These silages were subsequently fractionated into press-cake and press-juice fractions. Loss of soluble, fermentable organic matter during ensiling increased the relative proportions of fibre and crude protein. Fractionation resulted in the substantial reduction of herbage soluble nutrient and mineral content, increasing the fibre content and reducing digestibility and crude protein. The low energy and protein content of the press-cake fraction, especially at later harvest dates, will limit its use in ruminant diets.

This study investigated the effects of advancing stage of maturity and additive treatment on the fermentation characteristics of three common grassland species. Perennial ryegrass (PRG; Lolium perenne L., var. Gandalf), timothy (Phleum pratense L., var. Erecta) and red clover (Trifolium pratense L., var. Merviot) were harvested at three dates in the primary growth (11 May, 8 June and 6 July; Harvests 1–3) and ensiled with the following additive treatments: (1) control (i.e. no treatment), (2) formic acid-based additive, (3) homofermentative lactic acid bacterial (LAB) inoculant and (4) heterofermentative LAB inoculant. Additive application to the PRG (irrespective of harvest date), the late-harvest timothy (Harvest 3) and the red clover (Harvests 2 and 3) herbages had little impact on silage fermentation characteristics, where a lactic acid dominant fermentation already prevailed. However, the application of the formic acid-based additive to the Harvest 1 and 2 timothy and Harvest 1 red clover herbages, where the silage fermentation characteristics were poorer, resulted in an increase in the proportion of lactic acid in total fermentation products and a decrease in pH. In contrast, the heterofermentative LAB inoculant had a negative impact on silage fermentation characteristics where a poor preservation prevailed in the corresponding control silage.

Characterization of grass fibre is important in assessing its potential for industrial fibre applications. Stem and leaf sections were sampled from triplicate field plots of two grass species, perennial ryegrass (PRG) and tall fescue at three dates (monthly from 12 May) in the primary growth, and were used to (a) isolate individual fibre cells and (b) prepare transverse sections. Microscopy and image analysis software were used to determine the length and width of individual fibre cells and the proportion of lignified fibre in stem and leaf transverse sections. The length and width of individual fibre cells were greater (P 0·05) on the proportion of lignified fibre in the transverse-sectional area. However, there was a greater (P

Three of the main management factors affecting herbage chemical composition pre-ensiling are plant species, rate of nitrogen (N) fertilizer application and stage of maturity at harvest. This study investigated the effects of N fertilizer input and harvest date in the spring growth on the fermentation characteristics, dry matter recovery and aerobic stability of silages prepared from five common grass species. Perennial ryegrass (Lolium perenne cv. Gandalf), Italian ryegrass (Lolium multiflorum cv. Prospect), tall fescue (Festuca arundinacea cv. Fuego), cocksfoot (orchardgrass, Dactylis glomerata cv. Pizza) and timothy (Phleum pratense cv. Erecta) were grown under two inorganic N fertilizer inputs (0 and 125 kg N ha−1), harvested at five dates in the spring growth (fortnightly from 12 May to 7 July; Harvests 1 to 5, respectively) and subsequently ensiled in laboratory pipe silos for a period of 100 days. The ryegrass and tall fescue silages exhibited a lactic acid dominant fermentation and showed little evidence of secondary clostridial activity. In contrast, the challenge to preservation proved greater for the timothy (Harvests 1 and 2) and cocksfoot (Harvests 1 and 5) herbages, with the high pH (>4.2) and high butyric acid (>10 g kg−1 dry matter) and ammonia-N (>100 g kg−1 N) concentrations being indicative of secondary clostridial activity during storage. Despite the effects on herbage chemical composition prior to ensiling being indicative of a greater challenge to preservation, there was little effect of fertilizer N on the extent or direction of fermentation. Although the Italian ryegrass herbage avoided significant clostridial activity, this herbage incurred the greatest dry matter losses during ensiling. This was particularly evident at early harvest dates suggesting yeast fermentation of sugars, which were surplus to the requirement for a lactic acid dominant fermentation.

Infections with parasitic helminths (nematodes and trematodes) represent a significant economic and welfare burden to the global ruminant livestock industry. The increasing prevalence of anthelmintic resistance means that current control programmes are costly and unsustainable in the long term. Recent changes in the epidemiology, seasonality and geographic distribution of helminth infections have been attributed to climate change. However, other changes in environment (e.g., land use) and in livestock farming, such as intensification and altered management practices, will also have an impact on helminth infections. Sustainable control of helminth infections in a changing world requires detailed knowledge of these interactions. In particular, there is a need to devise new, sustainable strategies for the effective control of ruminant helminthoses in the face of global change. In this paper, we consider the impact of helminth infections in grazing ruminants, taking a European perspective, and identify scientific and applied priorities to mitigate these impacts. These include the development and deployment of efficient, high- throughput diagnostic tests to support targeted intervention, modelling of geographic and seasonal trends in infection, more thorough economic data and analysis of the impact of helminth infections and greater translation and involvement of end-users in devising and disseminating best practices. Complex changes in helminth epidemiology will require innovative solutions. By developing and using new technologies and models, the use of anthelmintics can be optimised to limit the development and spread of drug resistance and to reduce the overall economic impact of helminth infections. This will be essential to the continued productivity and profitability of livestock farming in Europe and its contribution to regional and global food security. View Full-Text

In vitro fermentation techniques (IVFT) have been widely used to evaluate the nutritive value of feeds for ruminants and in the last decade to assess the effect of different nutritional strategies on methane (CH4) production. However, many technical factors may influence the results obtained. The present review has been prepared by the 'Global Network' FACCE-JPI international research consortium to provide a critical evaluation of the main factors that need to be considered when designing, conducting and interpreting IVFT experiments that investigate nutritional strategies to mitigate CH emission from ruminants. Given the increasing and wide-scale use of IVFT, there is a need to critically review reports in the literature and establish what criteria are essential to the establishment and implementation of in vitro techniques. Key aspects considered include: i) donor animal species and number of animal used, ii) diet fed to donor animals, iii) collection and processing of rumen fluid as inoculum, iv) choice of substrate and incubation buffer, v) incubation procedures and CH measurements, vi) headspace gas composition and vii) comparability of in vitro and in vivo measurements. Based on an evaluation of experimental evidence, a set of technical recommendations are presented to harmonize IVFT for feed evaluation, assessment of rumen function and CH production., This review is part of the FACCE-JPI ‘Global Network’ project and the ‘Feeding and Nutrition Network’ of Livestock Research Group, in the Global Research Alliance for Agricultural Greenhouse Gases (www.globalresearchalliance.org). Authors acknowledge national funding from INIA (Spain, project MIT01-GLOBALNET-EEZ), the Ministry of Economic Affairs (The Netherlands; project Global Research Alliance on Agricultural Greenhouses Gases, BO-20-007-006), USDA-NIFA (USA), French National Research Agency through the program FACCE-JPI program, the Irish contribution to this JPI-FACCE project was funded by the Agricultural GHG Research Initiative for Ireland (AGRI-I), Department for Environment Food & Rural Affairs (UK), BLW (Switzerland) and Academy of Finland, Helsinki, Finland (Project 281337).

Ruminant husbandry is a major source of anthropogenic greenhouse gases (GHG). Filling knowledge gaps and providing expert recommendation are important for defining future research priorities, improving methodologies and establishing science-based GHG mitigation solutions to government and non-governmental organisations, advisory/extension networks, and the ruminant livestock sector. The objectives of this review is to summarize published literature to provide a detailed assessment of the methodologies currently in use for measuring enteric methane (CH) emission from individual animals under specific conditions, and give recommendations regarding their application. The methods described include respiration chambers and enclosures, sulphur hexafluoride tracer (SF) technique, and techniques based on short-term measurements of gas concentrations in samples of exhaled air. This includes automated head chambers (e.g. the GreenFeed system), the use of carbon dioxide (CO) as a marker, and (handheld) laser CH detection. Each of the techniques are compared and assessed on their capability and limitations, followed by methodology recommendations. It is concluded that there is no ‘one size fits all’ method for measuring CH emission by individual animals. Ultimately, the decision as to which method to use should be based on the experimental objectives and resources available. However, the need for high throughput methodology e.g. for screening large numbers of animals for genomic studies, does not justify the use of methods that are inaccurate. All CH measurement techniques are subject to experimental variation and random errors. Many sources of variation must be considered when measuring CH concentration in exhaled air samples without a quantitative or at least regular collection rate, or use of a marker to indicate (or adjust) for the proportion of exhaled CH sampled. Consideration of the number and timing of measurements relative to diurnal patterns of CH emission and respiratory exchange are important, as well as consideration of feeding patterns and associated patterns of rumen fermentation rate and other aspects of animal behaviour. Regardless of the method chosen, appropriate calibrations and recovery tests are required for both method establishment and routine operation. Successful and correct use of methods requires careful attention to detail, rigour, and routine self-assessment of the quality of the data they provide., This review is part of the FACCE-JPI ‘Global Network’ project. Authors acknowledge national funding from the Departmentfor Environment, Food and Rural Affairs (UK), INIA (Spain, project MIT01-GLOBALNET-EEZ), the Ministry of Economic Affairs(The Netherlands; project Global Research Alliance on Agricultural Greenhouses Gases, BO-20-007-006), USDA-NIFA (USA),French National Research Agency through the FACCE-JPI program, Agricultural GHG Research Initiative for Ireland (AGRI-I),Academy of Finland, Helsinki, Finland (Project 281337), and BLW (Switzerland).

The interaction of grassland management factors such as plant species, rate of nitrogen (N) fertiliser application and stage of maturity at harvest, will determine the optimal balance of herbage yi...

In a Green Biorefinery processing green biomass, one possible application for the press-cake fraction is as biomass fuel for combustion. In an industrial setting, the preservation of herbage as silage and its subsequent fractionation into press-juice and press-cake fractions represent the two major process steps in the utilization of green biomass. This study investigated (i) the effects of ensiling and fractionation on the chemical composition of three common temperate grassland species harvested at different stages of maturity and (ii) the suitability of the herbage of these species for thermal combustion. The high contents of ash, N, Cl and K in perennial ryegrass, cocksfoot and red clover, at both pre- and post-ensiling, make these materials less suitable for combustion in certain applications. The loss of soluble/fermentable organic matter during ensiling increased the relative proportions of fibre, ash and N in the herbage, but these changes were relatively minor. In contrast, the substantial reduction in the concentration of compounds such as ash, N, Cl and K during fractionation improved the suitability of the press-cake fraction for combustion compared with the parent material. Press-cake prepared from later-harvested grass herbage with lower ash, S and N contents would be more suitable for combustion.

The chemical composition of silage consumed by cattle can influence the subsequent rumen microbial fermentation patterns and methane (CH4) emissions. The objectives of this study were to (i) evaluate the effect of ensilage on the in vitro rumen methane output of perennial ryegrass and (ii) relate the silage fermentation characteristics of grass silages with in vitro rumen methanogenesis. Three pre-harvest herbage-conditioning treatments and seven silage-additive treatments were used in a laboratory-scale silo experiment to produce a diversity of silage fermentation characteristics. Ensilage reduced (P

The initial stage of a Green Biorefinery involves the fractionation of plant biomass into a fibre-rich press-cake and a nutrient-rich press-juice that are subsequently used to provide energy, chemicals and materials. However, limited information has been published to date on the factors influencing the fractionation of green biomass. Perennial ryegrass and cocksfoot silages harvested at two stages of maturity were subjected to hydrothermal conditioning at three temperatures (20, 40 and 60 °C) with or without detergent. In a second experiment, Italian ryegrass and timothy silages harvested at three stages of maturity were subjected to three washing steps (30 min at 60 °C in a 3 water + detergent (30 g L −1 ): 1 silage ratio; undertaken 1, 2 or 3 times), before being mechanically pressed at three different pressures (1.5, 3.0 or 4.5 MPa). Overall, repeated washing (up to 2 washing steps) and mechanical pressing (3.0 MPa) proved the most effective treatments for the removal of solubles from a range of grass silages and in the isolation of a fibre-rich press-cake fraction.

The objective of the study was to determine the effects of maize hybrid and harvest date on the yield, quality and subsequent conservation characteristics of whole-crop, cob and stover silages. The experiment had a split-plot design, with three main plots (date of harvest) and six subplots (hybrid) in each of three replicate blocks. Four maize hybrids (Tassilo, Beethoven, Andante and Nescio) were conventional hybrids used in commercial livestock production in Ireland, and two were categorized as high-biomass hybrids (Atletico and KXA 7211). The three harvest dates – 16 September, 7 October and 28 October – represented early, normal and late harvests respectively. Averaged across hybrids, harvesting on 16 September reduced the DM yield (P

SUMMARYThe objectives of the present study were to determine the effects of nitrogen (N) application rate, harvest date and maize cultivar on the yield, quality and the subsequent conservation characteristics of whole-crop, cob and stover silages. The experiment was organized in a spilt-plot design, with harvest date (15 September, 6 October and 27 October) as the main plot, and a three (maize cultivars: Tassilo, Andante and KXA 7211)×two (N application rate: 33 and 168 kg N/ha) factorial arrangement of treatments as the sub-plot, within three replicate blocks, and was conducted at Grange, Dunsany, Co. Meath, Ireland in 2009. The three harvest dates represented early, normal and late harvests, respectively, for a midland site in Ireland. Of the three maize cultivars selected, cvars Tassilo and Andante represent conventional cultivars sown by commercial livestock farmers in Ireland, while cvar KXA 7211 is categorized as a high biomass cultivar. No effect of N application rate was observed on the dry matter (DM) yield, nutritive value or ensiling characteristics of maize whole-crop or cob. Whole-crop and stover harvested on the later date had a lower digestible DM (DDM) content and the silages underwent a more restricted fermentation, compared to silages produced from herbage harvested on earlier dates. Cob silages produced from crops harvested on 15 September had lower DDM content and higher DM loss during ensiling than later harvest dates. Despite higher whole-crop DM yields, the later maturing cultivar KXA 7211 did not improve the DM yields of cob and also resulted in increased DM losses from the ensilage of cob, when compared with the other cultivars. In addition to the DM yield and nutritive value of forage maize at harvest, the subsequent fermentation profile during ensilage influences the optimum choice of cultivar and date for crop harvest in a maize silage production system.