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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.

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.

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.

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.

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

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.

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.

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

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.

SUMMARYPerennial ryegrass evaluation schemes categorize varieties into three maturity (early, intermediate and late) and two ploidy (diploid and tetraploid) groups, and compare the relative yield, persistence and nutritive quality of varieties within these groups. The present study compared these groups for herbage yield, dry matter (DM) concentration and, using near infrared reflectance spectroscopy (NIRS), four quality characteristics (in vitrocontent of digestible dry matter (CDDM), water-soluble carbohydrate (WSC) and crude protein (CP) concentrations, and buffering capacity). A total of 1208 plots were sown across 5 years in Irish Recommended List trials and then harvested 6–7 times in each of 2 harvest years. This also allowed an assessment of the effect of sward age. Maturity group had no significant effect on annual herbage yield, quality or DM concentration except forin vitroCDDM (Pin vitroCDDM (PP<0·01) and buffering capacity (P<0·05) at the first silage harvest. Tetraploid swards had greater annual herbage yields (P<0·001),in vitroCDDM values (P<0·001) and WSC concentrations (P<0·01), but lower CP and DM concentrations (P<0·001) than diploids. Swards in their first full year produced an additional 5·17 t/ha DM (P<0·001) and had a higher (P<0·01) WSC concentration at the second silage harvest than in their second year, but did not differ significantly forin vitroCDDM and WSC, CP or DM concentrations. The present study showed that differences exist in yield, nutritive quality and ensilability indices between maturity and ploidy groups. These observations justify their assessment in variety comparative trials and facilitates particular groups being selected for individual farming systems to increase efficiency.

The selection and feeding of perennial ryegrass (Lolium perenne L.) varieties (PRV) or perennial grass species (PGS) may affect enteric methane (CH4) output because of changes in the fermentation dynamics in the rumen as a result of differences in herbage chemical composition. The objective of this study was to determine the effects of PRV and PGS harvested throughout the growing season on herbage chemical composition, and in vitro rumen fermentation variables and CH4 output per unit of feed using a batch culture technique. Seven PRV (Experiment 1: Alto, Arrow, Bealey, Dunluce, Greengold, Malone, Tyrella) and six perennial grasses [Experiment 2: perennial ryegrass (Navan), perennial ryegrass (Portstewart), cocksfoot, meadow fescue, tall fescue, timothy; defined as PGS], managed under a simulated grazing regime, were incubated for 24 h with buffered rumen fluid in two separate experiments. The CH4 output per unit of feed dry-matter (DM) incubated was not affected (P >0 AE05) by PRV (range of mean values across PRV of 23AE9–25AE3 (SEM 0AE41) mL g )1 DM) or by PGS (25AE6–26AE6 (SEM 0AE37) mL g )1 DM). The CH4 output per unit feed DM disappearing during the in vitro rumen incubation was not affected by PRV (33AE9–35AE1 (SEM 0AE70) mL g )1 DM), and although there was an overall PGS effect (P

Increasing the residual water-soluble carbohydrate (WSC) concentration in silage may improve the nutritional value but impair aerobic stability. Our aim was to determine whether the residual WSC concentration and aerobic stability of low dry-matter (

The Grange Feed Costing Model was modified to simulate the economic implications of grassland management strategies for a grass-based suckler beef calf-to-weanling system at the whole-farm level. The modified model enabled costing of annual grass consumed as grazed grass and silage when the farm grazing and conservation areas are integrated. Grass growth data from sites in the south, east and north of Ireland were used. Sixty-three scenarios were simulated, enabling analysis of site, stocking rate and silage strategy effects on total annual feed cost for the grass forage production system. Total annual feed cost (of grazed grass and grass silage) ranged from €96 to €111 per 1000 UFL (Unite Fourragere Lait) and €411 to €456 per beef cow unit (CU). The silage strategy with respect to the number of harvests and whether the silage area was grazed in the spring had negligible impact on annual total feed cost per CU. However, a tendency towards reduced annual feed cost under a two harvest, relative to a one harvest, silage strategy was observed. The lowest cost stocking rate was 2 CU ha−1. Site-specific differences such as seasonal growth distribution and nitrogen fertilizer response rate had the greatest influence on the annual cost of the grass-based feeding system.

SUMMARYAn agro-economic simulation model was developed to facilitate comparison of the impact of management, market and biological factors on the cost of providing ruminant livestock with feed grown on the farm (home produced feed). Unpredictable year-to-year variation in crop yields and input prices were identified as quantifiable measures of risk affecting feed cost. Stochastic analysis was used to study the impact of yield and input price risk on the variability of feed cost for eight feeds grown in Ireland over a 10-year period. Intensively grazed perennial ryegrass was found to be the lowest cost feed in the current analysis (mean cost €74/1000 Unité Fourragère Viande (UFV)). Yield risk was identified as the greatest single factor affecting feed cost variability. At mean prices and yields, purchased rolled barley was found to be 3% less costly than home-produced spring-sown barley. However, home-produced spring barley was marginally less risky than purchased barley (coefficient of variation (CV) 0·063 v. 0·064). Feed crops incurring the greatest proportion of fixed costs and area-dependent variable costs, including bunker grass silage, were the most sensitive to yield fluctuations. The most energy input-intensive feed crops, such as grass silage, both baled and bunker ensiled, were deemed most susceptible to input price fluctuations. Maize silage was the most risky feed crop (CV 0·195), with potential to be both the cheapest and the most expensive conserved feed.

The effectiveness of the polyethylene stretch-film barrier to air infiltration is the major factor affecting the preservation of silage in bales. Three separate experiments investigated the effects of the number of layers of stretch-film cover, film colour, stretch extent, film type and frequency of bale handling on gas composition, surface mould growth and conservation characteristics of baled grass silages. Monitoring gas composition in bales during ensiling proved useful for assessing the success with which wrapped bales were stored anaerobically. Under good storage conditions the early stages of ensiling were characterized by the rapid reduction of O2 concentration in the bale and the creation of a CO2-rich environment. However, wrapping bales in only two layers of stretch-film failed to create the anaerobic conditions required for a successful fermentation and the inhibition of visible fungal growth. In contrast, a minimum of four layers of stretch-film were required to achieve suitably anaerobic conditions, but the additional benefits of applying more layers were relatively small. Under temperate climatic conditions with moderate solar radiation, film colour had little effect on the gas composition in baled silage. Likewise, the extent of stretching applied to the film at wrapping and film type had no influence on gas composition, baled silage quality or mould development. However, frequent mechanical handling of bales after wrapping had a negative effect on gas composition and surface mould growth, and thus should be kept to a minimum.

The composition of baled silage frequently differs from that of comparable conventional silage. A factorial experiment was conducted with three wilting treatments (0, 24 or 48 h) × three ensiling systems [unchopped grass in bales, unchopped grass in laboratory silos (LS), precision-chopped grass in LS] × six stages of ensiling to (i) confirm that the fermentation of unchopped grass in LS could be used as an adequate model for baled silage fermentation, (ii) quantify the differences between baled silage and silage made from precision-chopped herbage across a range of dry-matter contents and (c) quantify the fermentation dynamics within the various treatments. The onset of fermentation as evidenced by the accumulation of fermentation products and the decline in pH were slower (P

The extent of visible fungal growth and the identity of the predominant fungi causing spoilage of baled grass silage were recorded on 180 farms in Ireland. Fungal growth was evident on bales on 174 of the 180 farms visited and on 331 of the 360 bales examined. The mean proportion of surface area of bale, that was affected, was 0·06. Silage-making method, storage characteristics and geographical location were significantly associated with the level of fungal contamination on bales. Fungal contamination was higher (P

Perennial ryegrass (Lolium perenne L.) is by far the most widely sown grass species in Ireland. Genotype · environment (G · E) interactions are a frequent occurrence in herbage yield evaluations. The objectives were to determine (i) the nature and relative magnitudes of the pertinent G · E interaction variance components for dry matter yield of perennial ryegrass sward plots in Ireland and (ii) the optimal allocation of replicates, locations and years in a testing programme. Sixteen perennial ryegrass cultivars were sown at six locations throughout Ireland between 2000 and 2004. Plots from each sowing were harvested for 2 consecutive years under a simulated mixed grazing and conservation management programme. The largest component of the G · E variance was generally genotype · location · year emphasizing the need for evaluation of genotypes across locations and years to adequately characterize genotypes for differences in yield. Relative differences among genotypes from year to year and location to location were due mainly to changes in genotype rankings. Weather was estimated to have a greater effect on annual variation in herbage yield than age of stand. The optimum allocation of resources for a testing programme was estimated at four replicates per location, and either two locations and 3 sowing years or three locations and 2 sowing years with 2 harvest years for each sowing year. The most appropriate option depends on the relative importance of time vs. financial resources.

Forage dry matter yield (DMY) is a high-priority trait in breeding perennial ryegrass (Lolium perenne L.). However, determining dry matter concentration is highly labor intensive. For a similar level of resources, indirect selection based on fresh matter yield (FMY) would allow a greater number of replicates, genotypes, or both to be evaluated. Our objective was to estimate the effi ciency of indirect selection for DMY based on FMY of pure perennial ryegrass sward plots. Over a 14-yr period, replicated trials, containing perennial ryegrass genotypes of similar ploidy and maturity category, were sown in Ireland and assessed for DMY and FMY at each harvest over two consecutive years. Forage was generally surface dry when harvested. The estimated effi ciency of indirect selection based on two replicates and comparable selection intensity was high (≥0.80). Simulation models indicated that resources would be used more effi ciently by evaluating more genotypes than by increasing the number of replicates. For example, doubling the number of plots to increase the number of replicates from two to four indicated an increase in the effi ciency of indirect selection from a mean 0.88 to 0.94. However, doubling the number of plots and including more genotypes, facilitating greater selection intensity, indicated an increase in the effi ciency of indirect selection from a mean 0.88 to 1.04. This study indicates that FMY can be used successfully as an indirect selection method of increasing DMY in perennial ryegrass swards.

Summary The chemical composition of baled silage frequently differs from that of comparable conventional silage. The extents of wilting, chopping, compaction and air infiltration potentially contribute to these differences in conservation characteristics. An experiment was organized in a 3 (0, 24 or 48-h wilting to influence herbage dry-matter content) × 2 (unchopped or chopped) × 2 (with or without compaction) × 2 (with or without air infiltration) factorial arrangement of treatments, to elucidate the relative effects of these factors on the conservation characteristics of ensiled grass. Dry-matter content of herbage and infiltration of air had a greater effect on silage conservation characteristics than chopping and compaction. The main interactions were between wilting and air infiltration, wilting and compaction, and compaction and air infiltration. Air infiltration stimulated a secondary fermentation in the unwilted herbage, reflected in a large increase (P

This experiment quantified the effects of: (i) heading date of perennial ryegrass, (ii) grazing frequency in spring and (iii) date of silage harvest, on the ensilability of herbages harvested for silage, and on the conservation and estimated nutritive value of the resultant silages. Replicated field plots with two perennial ryegrass mixtures (intermediate- and late-heading cultivars) were subjected to three spring-grazing regimes (no grazing, grazing in late March and grazing in both late March and late April) and were harvested on four first-cut harvest dates between 20 May and 21 June. Herbage from each of the four replicates of these 24 treatments was precision-chopped and ensiled unwilted and with no additive in laboratory silos. Herbage from the sward with the intermediate-heading cultivar had a higher (P

Recent reform of European agricultural policy has resulted in substantial changes to the criteria by which premia payments are made. Beef farmers, who have been particularly dependent on premia payments to maintain margins, must re-evaluate their systems to identify optimal systems in these new circumstances. A mathematical model, the Grange Beef Model, is presented and used to identify optimal beef production systems in Ireland. The objective function maximises farm gross margin and the model is primarily constrained by animal nutritional requirements. Model applications are illustrated through the analysis of a series of scenarios concerning variation in beef and concentrate prices; technical development through the integration of an alternative forage and the impacts of participation in an agri-environmental scheme.

There are potential advantages and disadvantages associated with grazing spring perennial ryegrass swards designated for first-cut silage. These may differ for intermediate-heading (0·50 ear emergence in the second half of May) and late-heading (0·50 ear emergence in the first half of June) cultivars. The interactions between cultivar type, spring-grazing frequency, silage-harvest date and year were examined in an experiment with a randomized complete block (n = 4) design with a factorial arrangement of treatments, conducted in Ireland. The factors were (i) two perennial ryegrass mixtures: intermediate- vs. late-heading cultivars, (ii) three spring-grazing regimes: no grazing, grazing in mid-March or grazing in both mid-March and mid-April, (iii) four first-cut silage-harvest dates that were at c. 10-d intervals from 19 May and (iv) 2 years (1998 and 1999). The effects of cultivar mixture on herbage mass of the swards in spring were small and not statistically significant. The late-heading cultivars provided lower amounts of herbage dry matter for harvesting for first-cut silage but herbage with higher in vitro organic digestibility values compared with intermediate-heading cultivars. To achieve the same amount of herbage for silage, the late-heading cultivars needed to be harvested 8 d later than the intermediate-heading cultivars. Even with this delay in harvest date, the late-heading cultivars had higher in vitro organic digestibility values than the intermediate-heading cultivars. The late-heading cultivars could be harvested up to 30 d later and produce a higher amount of herbage for first-cut silage with similar digestibility values compared with the intermediate-heading cultivars.

The scale of damage caused by vertebrates to the plastic wrap on baled silage was evaluated on Irish farms. A survey was conducted on 300 farms representative of farming systems and geographical locations throughout Ireland. The scale of damage was classified as farms with 0%, 1-10%, 11-50% or 51-100% of bales with holes in the plastic wrap caused by birds. The proportion of farms within these four classes with damage caused by birds during the short interval between wrapping and removal from the field to storage was 47%, 37%, 15% and 1% of the total, respectively. Correspondingly, during the subsequent storage prior to feedout, bird damage was 37%, 50%, 12%, and 1%. Similarly, the proportions for damage throughout long-term storage due to cats were 71%, 23%, 6% and 0%, while the incidence of damage caused by rats, dogs and farm livestock was comparatively small. The stored bales were fenced against livestock on 86% of farms, while netting, bale painting and other protection methods were used to discourag...

A factorial experiment was carried out to evaluate the effects of level of nitrogen (N) application to grassland and subsequent treatment of the herbage at ensiling with formic acid on the rate of silage fermentation, dry-matter (DM) recovery, aerobic stability and effluent production. Herbage from the primary regrowth of predominantly perennial ryegrass swards received either 72 (LN), 126 (MN) or 180 (HN) kg N ha−1. The herbages were harvested and yield estimated after a 50-day regrowth interval. After storage for 24 h in polythene bags, the herbages were ensiled, unwilled, in laboratory silos (6 kg capacity) either untreated (UT) or treated with formic acid (F) at 3 ml (kg herbage)−1. Three silos per treatment were opened and sampled on days 1, 3, 6, 15, 50 and 105 after ensiling. The mean herbage yields for the LN, MN and HN swards were 5.2, 6.3 and 6.2 (s.e. = 0.27) t DM ha−1 and there was no carryover effect of nitrogen treatment on the yield of a subsequent 22-day regrowth harvested on 2 September. As level of fertilizer N application increased, concentrations in the herbage at mowing of crude protein, nitrate and ash increased, DM decreased and water-soluble carbohydrate and in vitro DM digestibility remained unchanged. Increasing the rate of N fertilizer to the sward resulted in higher silage pH (P 0.05) on DM recovery. It is concluded that the rate and extent of pH decline was reduced with increasing N application, associated with increased buffering capacity and decreased DM concentrations of the herbage at ensiling. However, increasing the level of N fertilizer applied increased DM recovery and effluent output, and improved aerobic stability of the resulting silages.

In Ireland, grass is a readily available bioresource. It has previously been established that Green biorefinery (GBR) could become a potential use of Irish grasslands, and a blueprint for a sustainable GBR industry in Ireland has been developed. The objective of this paper is to use scenario analysis to investigate the sensitivity of the profitability of the GBR blueprint to variations in grass quantity and quality as a function of botanical composition, fertiliser application, and biomass availability. As an outcome of these scenario analyses, the price the GBR can offer to farmers above their production costs (€ t −1 dry matter) was calculated. Results of the scenario analyses determined that GBR systems located in a catchment area of permanent pasture ( Lolium perenne > 60%) with annual grass yields in the range of 9–12 t dry matter (DM) ha −1 , and supplied with grass biomass with a fibre content of 500–555 g kg −1 DM and a protein content of 110–130 g kg −1 DM, were viable. The most profitable scenarios were generated when nitrogen fertiliser application was greater than 90 kg ha −1 a −1 . Biomass availability of less than 30% resulted in reduced profitability and for some scenarios resulted in a loss for both the GBR and farmer due to increased transport costs. Within the scenario assumptions of this study, grass feedstock was valued at €4–€56 t −1 dry matter above production costs. However, this value depended on the yields and biomass availability of the GBR catchment area.

Lucerne (Medicago sativa L) silages made in test tube silos at various dry matter (DM) levels (290-537 g kg−1) with and without addition of glucose (20 g kg−1 herbage) at ensiling were stable during 7 days of aerobic exposure. Lucerne silages taken from seven farm silos were similarly stable while three others were unstable (average DM loss of 62 g kg−1 DM and pH increase from 4.35 to 7.58 in 7 days). Under similar circumstances, maize (Zea mais L) silage had a high DM loss (164 g kg−1 DM) and an increase in pH from 3.94 to 8.13. Silages were inoculated with yeast (1 × 106 CFU g−1 silage) isolated from aerobically deteriorating farm-scale lucerne and maize silages. The stable lucerne silages were not destabilised by inoculation, but the instability of unstable lucerne silages was increased. Aerobically unstable maize silage and stable lucerne silage were inoculated and studied separately or as a 50:50 mixture. There was a distinct lag in the development of aerobic instability in the mixture compared with maize silage alone. In another experiment, the growth of the inoculum in malt agar (pH 3.5) as affected by the presence of fresh and ensiled lucerne (six cultivars), birdsfoot trefoil (Lotus corniculatus L) and red clover (Trifolium pratense L) was studied. The legume herbages did not inhibit yeast growth whereas the corresponding silages did. Five aerobically stable lucerne silages inhibited yeast development in the media whereas unstable maize silage did not. It is concluded that aerobic stability was not related to silage DM, pH, yeast numbers or glucose addition at ensiling. Stability appeared to be due to the presence of an inhibitor (or inhibitors) produced during ensilage.

Eleven laboratory lucerne silages, ten farm-scale lucerne silages and one maize silage were analysed for fermentation products to determine if chemical composition could explain differences in aerobic stability. Three of the farm-scale lucerne silages and the maize silage heated within 4 days of exposure to air whereas the other lucerne silages were stable for longer than 7 days even after inoculation with a destabilising yeast inoculum. The silages were analysed for lactic acid, volatile fatty acids (C1 to C6), succinic acid, ethanol, and 2,3-butanediol. The concentrations of these compounds in the unstable silages were not different from levels found in stable silages on either a dry matter basis or an undissociated water basis. However, unstable silages tended to be lower in 2,3-butanediol than other silages. The time until heating in these silages was simulated using a model of aerobic fungal growth in silage. This model considered the effects of yeast and mould numbers, pH, moisture content, and lactic and acetic acid concentrations on stability. Aerobic stability in three of the four unstable silages, with and without inoculation of destabilising yeasts, was reasonably predicted by the model. Stability in the other silages was consistently underpredicted by the model. These results indicate that the stability factor found in many lucerne silages is unlikely to be one of the principal products of silage fermentation.