• Key factors influencing economic relationships and communication in European agri-food chains

      Henchion, Maeve; McIntyre, Bridin; Downey, Gerard (Teagasc, 2008-09)
      The project considered meat and cereal commodities in six EU countries. In total thirteen agri-food chains were examined: five pig-to-pigmeat chains, three cattle-to-beef chains, two barley-to-beer chains and three cereals-to-bakery product chains. The pig-to-pigmeat and cattle-to-beef chains were examined in Ireland.
    • Key factors influencing economic relationships and communication in European agri-food chains

      Henchion, Maeve; McIntyre, Bridin; Downey, Gerard (Teagasc, 2008-09-01)
      This report reflects the Irish contribution to an EU-funded project which aimed to: clarify the relevance of business-to-business relationships and communication in European agri-food chains, and identify the economic, social and cultural factors that influence agri-food chain relationships and business-to-business communication. Such research was expected to be of use to companies seeking to develop more sustainable business relationships.The project considered meat and cereal commodities in six EU countries. In total thirteen agri-food chains were examined: five pig-to-pigmeat chains, three cattle-to-beef chains, two barley-to-beer chains and three cereals-to-bakery product chains. The pig-to-pigmeat and cattle-to-beef chains were examined in Ireland.
    • Laboratory Development of a Passive Proportional Sampler for Overland FlowStudies in Agricultural Fields

      Ryan, T. Declan; Forristal, Dermot (Canadian Society for Bioengineering / Société Canadienne de Génie Agroalimentaire et de Bioingénierie, 2015-02-06)
      Water-quality in many rivers remains poor and needs to be improved. Diffuse pollution continues to cause difficulties. Some instruments are available which can monitor pollution of rivers from land. They allow measurement and sampling of overland flow (OLF), but they do not offer the precision required (proportional sampling and samples 0.1% of OLF). A laboratory unit was constructed to mimic instrument performance in the field. This was used to test three sampler designs. A V-notch weir was used in the first sampler and a Sutro weir in the second and third as this unit possessed a proportional discharge to head ratio, which the Vnotch weir did not have. Other parameters investigated included ground slope, sampler slope, pipe size and port location. The remaining issues of nozzle size (0.7, 1.0 and 2.0 mm), the number of 1.0 mm nozzles and the effect of aspiration were investigated. The arrangement with the Sutro weir and three 1.0 mm nozzles in series gave proportional discharge and the target low sampling rate of 0.1%. This will allow the calculation of sediment and chemical losses for the monitored area and will put the loss in context with other losses in a catchment.
    • A laboratory study of the effects of water dissolved gypsum application on hydraulic conductivity of saline-sodic soil under intermittent ponding conditions

      Sahin, U.; Anapali, O. (Teagasc (Agriculture and Food Development Authority), Ireland, 2005)
      Reclamation of saline-sodic soils has great importance in agricultural management. The objective of this study was to evaluate the effectiveness of the methods used to apply water and gypsum on hydraulic conductivity of a saline-sodic soil with an electrical conductivity of 28 dS/m and exchangeable sodium percentage of 46%. The experiment was conducted under laboratory conditions using disturbed and non-cropped soil columns. A total of 45 cm of water was applied to each column with 3, 6, or 9 separate water applications. Finely ground gypsum (< 0.5 mm maximum particle diameter) was either incorporated into the surface 2 to 3 cm of soil or was dissolved into the leaching water at a rate corresponding to 3.82 t/ha. Six or nine separate water applications of gypsum dissolved into leaching water significantly increased hydraulic conductivity (P < 0.01). Soil hydraulic conductivity increased (P < 0.01) with depth at separate applications of gypsum.
    • Labour efficiency on-farm

      O'Brien, Bernadette; Gleeson, David E; O’Donovan, K.; Ruane, D.; Kinsella, J.; Mee, John F; Boyle, Laura; McNamara, John (Teagasc, 2007-01-01)
      Improvements in milking efficiency have a greater influence than any other aspect of the dairy farmers work on overall farm labour inputs (Whipp, 1992). In order to facilitate the examination of milking process labour inputs, the milking process may be divided into the following three components: herding pre and post milking (transfer of cows to and from the milking parlour); milking (milking tasks / work routines within the parlour); and washing (washing of milking machine and yard). Meanwhile, within milking specifically, the number of cows milked per operator per hour is the best measure of both the performance of the operator and the milking installation (Clough, 1978). This is affected by the following three factors: the milking times of the cows, the number and arrangement of the milking units, and the operator’s work routine (Whipp, 1992). The addition of extra milking units will only increase milking performance if the operator has idle time during milking (Hansen, 1999).
    • Lactobacillus ruminis strains cluster according to their mammalian gut source

      O’Donnell, Michelle M.; Harris, Hugh M B; Lynch, Denise B; Ross, R Paul; O’Toole, Paul W. (Biomed Central, 2015-04-01)
      Background Lactobacillus ruminis is a motile Lactobacillus that is autochthonous to the human gut, and which may also be isolated from other mammals. Detailed characterization of L. ruminis has previously been restricted to strains of human and bovine origin. We therefore sought to expand our bio-bank of strains to identify and characterise isolates of porcine and equine origin by comparative genomics. Results We isolated five strains from the faeces of horses and two strains from pigs, and compared their motility, biochemistry and genetic relatedness to six human isolates and three bovine isolates including the type strain 27780T. Multilocus sequence typing analysis based on concatenated sequence data for six individual loci separated the 16 L. ruminis strains into three clades concordant with human, bovine or porcine, and equine sources. Sequencing the genomes of four additional strains of human, bovine, equine and porcine origin revealed a high level of genome synteny, independent of the source animal. Analysis of carbohydrate utilization, stress survival and technological robustness in a combined panel of sixteen L. ruminis isolates identified strains with optimal survival characteristics suitable for future investigation as candidate probiotics. Under laboratory conditions, six human isolates of L. ruminis tested were aflagellate and non-motile, whereas all 10 strains of bovine, equine and porcine origin were motile. Interestingly the equine and porcine strains were hyper-flagellated compared to bovine isolates, and this hyper-flagellate phenotype correlated with the ability to swarm on solid medium containing up to 1.8% agar. Analysis by RNA sequencing and qRT-PCR identified genes for the biosynthesis of flagella, genes for carbohydrate metabolism and genes of unknown function that were differentially expressed in swarming cells of an equine isolate of L. ruminis. Conclusions We suggest that Lactobacillus ruminis isolates have potential to be used in the functional food industry. We have also identified a MLST scheme able to distinguish between strains of L. ruminis of different origin. Genes for non-digestible oligosaccharide metabolism were identified with a putative role in swarming behaviour.
    • Lactoferrin affects the adherence and invasion of Streptococcus dysgalactiae spp. dysgalactiae in mammary epithelial cells

      O'Halloran, Fiona; Beecher, Christine; Chaurin, Valerie; Sweeney, Torres; Giblin, Linda (Elsevier, 2016-03-24)
      Streptococcus dysgalactiae ssp. dysgalactiae is an important causative agent of bovine mastitis worldwide. Lactoferrin is an innate immune protein that is associated with many functions including immunomodulatory, antiproliferative, and antimicrobial properties. This study aimed to investigate the interactions between lactoferrin and a clinical bovine mastitis isolate, Strep. dysgalactiae ssp. dysgalactiae DPC5345. Initially a deliberate in vivo bovine intramammary challenge was performed with Strep. dysgalactiae DPC5345. Results demonstrated a significant difference in lactoferrin mRNA levels in milk cells between the control and infused quarters 7 h postinfusion. Milk lactoferrin levels in the Strep. dysgalactiae DPC5345 infused quarters were significantly increased compared with control quarters at 48 h postinfusion. In vitro studies demonstrated that lactoferrin had a bacteriostatic effect on the growth of Strep. dysgalactiae DPC5345 and significantly decreased the ability of the bacteria to internalize into HC-11 mammary epithelial cells. Confocal microscopy images of HC-11 cells exposed to Strep. dysgalactiae and lactoferrin further supported this effect by demonstrating reduced invasion of bacteria to HC-11 cells. The combined data suggest that a bovine immune response to Strep. dysgalactiae infection includes a significant increase in lactoferrin expression in vivo, and based on in vitro data, lactoferrin limits mammary cell invasion of this pathogen by binding to the bacteria and preventing its adherence.
    • Lactoferrin affects the adherence and invasion of Streptococcus dysgalactiae ssp. dysgalactiae in mammary epithelial cells

      O'Halloran, Fiona; Beecher, Christine; Chaurin, Valerie; Sweeney, Torres; Giblin, Linda (Elsevier, 2016-03-24)
      Streptococcus dysgalactiae ssp. dysgalactiae is an important causative agent of bovine mastitis worldwide. Lactoferrin is an innate immune protein that is associated with many functions including immunomodulatory, antiproliferative, and antimicrobial properties. This study aimed to investigate the interactions between lactoferrin and a clinical bovine mastitis isolate, Strep. dysgalactiae ssp. dysgalactiae DPC5345. Initially a deliberate in vivo bovine intramammary challenge was performed with Strep. dysgalactiae DPC5345. Results demonstrated a significant difference in lactoferrin mRNA levels in milk cells between the control and infused quarters 7 h postinfusion. Milk lactoferrin levels in the Strep. dysgalactiae DPC5345 infused quarters were significantly increased compared with control quarters at 48 h postinfusion. In vitro studies demonstrated that lactoferrin had a bacteriostatic effect on the growth of Strep. dysgalactiae DPC5345 and significantly decreased the ability of the bacteria to internalize into HC-11 mammary epithelial cells. Confocal microscopy images of HC-11 cells exposed to Strep. dysgalactiae and lactoferrin further supported this effect by demonstrating reduced invasion of bacteria to HC-11 cells. The combined data suggest that a bovine immune response to Strep. dysgalactiae infection includes a significant increase in lactoferrin expression in vivo, and based on in vitro data, lactoferrin limits mammary cell invasion of this pathogen by binding to the bacteria and preventing its adherence.
    • Lamb Growth Rate On Pasture : Effect Of Grazing Management, Sward Type And Supplementation

      Grennan, E.J. (Teagasc, 1999-01-01)
      In spring-lambing flocks an important objective is to achieve high lamb growth rate on pasture so that most lambs are drafted for slaughter by September. Lamb growth rate can vary greatly depending on the type of pasture being grazed. A series of grazing trials was carried out to assess the effect of pasture type, sward height, herbage allowance and concentrate supplementation on lamb growth rate pre and post weaning. Sward height was a useful indicator of the suitability of pasture for sheep grazing. A height of about 6 cm was near optimum for set stocking until late May. A decline in lamb growth rate frequently experienced in the month pre-weaning in June can largely be prevented if sward height is increased to 6 to 8 cm, or the flock grazed on aftergrass at a similar height. With rotational grazing, tight grazing to a residual sward height of 4 cm was beneficial in preventing the pasture becoming stemmy in June but reduced lamb weaning weight. Tight grazing in April when pasture is leafy is less restrictive on lamb growth than in June when the base of the sward is more stemmy. Post grazing heights of 4, 5 and 6 cm for April, May and June respectively, are suggested as a guide in order to achieve high lamb growth. There was a response to creep-feeding lambs. When concentrates were offered at 250 g/lamb/day from age 5 to 14 weeks the extra liveweight at weaning was associated with feed conversion ratios of 4.4 to 6.3 Creep grazing increased lamb weaning weight by over 2 kg and facilitated grazing the pastures tightly in June without penalising lamb growth. Lamb growth to weaning was better on pasture not grazed by sheep in the previous year and this benefit was at least partly attributable to lower level of parasites on the pasture. Lamb growth rate on pasture post-weaning varied greatly, from under 100 to over 200 g/day depending on the type of pasture grazed. For set stocking a sward height of 8 to 9 cm was required to maximise lamb growth. For rotational grazing, swards should be grazed down to about 6 cm. However the effect of sward height is modified by previous grazing management, in that tight grazing pre-weaning results in a more leafy pasture and higher lamb growth at comparable sward heights post-weaning. Pasture type also affected lamb growth. There was little difference between old permanent pasture and a mainly perennial ryegrass pasture when grazed at similar sward heights, or when lambs were given similar herbage allowances. However growth rates were considerably higher on grass/clover swards at equivalent allowances or similar sward heights. There was a close relationship between herbage allowance and lamb growth, with highest growth rate achieved at an allowance of about 5 kg of dry matter per lamb per day. Concentrate supplementation of weaned lambs on pasture (at 250 to 550 g/lamb/day) increased liveweight, carcass weight and kill-out proportion. Response to concentrates was slightly better on short grass. Feed conversion ratio for carcass gain ranged from 7 to 12 on short grass, 7 to 20 on long grass and was 14 when concentrates were offered ad libitum. Concentrate supplementation resulted in a higher proportion of lambs being drafted off pasture by late September (90 to 100 %) compared with 60 to 65% for lambs on grass only.
    • Land Applicaiton of Organic Manures and Silage Effluent

      Mulqueen, J.; Rodgers, M.; Bouchier, H. (Teagasc, 1999-11-01)
      In recent times there is increasing interest in the hydraulic properties of free-draining unsaturated soils and on the fate of slurries, sludges, effluents and fertilisers applied to these soils. This is especially so where relatively thin soils overlie bedrocks such as limestones with fissures and solution channels (karstic aquifers). Irish soils are commonly gravelly and stony and present special problems in determining their hydraulic properties. In this project, various field and laboratory methods were employed to measure the hydraulic conductivity of unsaturated gravelly and stony soils overlying karstic limestone with a watertable 25 m below ground surface at the Teagasc Centre at Athenry. In parallel with these measurements, cattle and pig slurries and silage effluents were applied at normal and very heavy rates in summer and in winter to a series of experimental plots. A chloride tracer was also used. Rainfall and soil moisture contents and hydraulic potentials of the soil of the various plots were measured. Samples of soil water were collected in suction tubes and analysed for nitrate nitrogen (NO3-N). In addition, samples of groundwater were taken from a nearby well and analysed for NO3-N and a number of other parameters. Finally, a finite difference computer model was used to predict contaminant transport to the groundwater.
    • Land Drainage - A farmer’s practical guide to draining grassland in Ireland

      Tuohy, Patrick; Fenton, Owen; O'Loughlin, James; Humphreys, James (Teagasc, 2013-07-30)
      No drainage work should be carried out before the drainage characteristics of the soil are established by a site and soil test pit investigation. • Two types of drainage system exist: a groundwater drainage system and a shallow drainage system. The design of the system depends entirely on the drainage characteristics of the soil. • Distinguishing between the two types of drainage systems essentially comes down to whether or not a permeable layer is present (at a workable depth) that will allow the flow of water with relative ease. If such a layer is evident, a piped drain system at that depth is likely to be effective. If no such layer is found during soil test pit investigations, it will be necessary to improve the drainage capacity of the soil. This involves a disruption technique such as moling, gravel moling or subsoiling in tandem with collector drains. • Drains are not effective unless they are placed in a free draining soil layer or complimentary measures (mole drainage, subsoiling) are used to improve soil drainage capacity. If water is not moving through the soil in one or other of these two ways, the water table will not be lowered. • Outfall level must not dictate the drainage system depth. If a free draining layer is present, it must be utilised. • Drain pipes should always be used for drains longer than 30 m. If these get blocked it is a drainage stone and not a drainage pipe issue. • Drainage stone should not be filled to the top of the field trench except for very limited conditions (the bottom of an obvious hollow). Otherwise it is an extremely expensive way of collecting little water. • Most of the stone being used for land drainage today is too big. Clean aggregate in the 10–40 mm (0.4 to 1.5 inch approx) grading band should be used. Generally you get what you pay for. • Subsoiling is not effective unless a shallow impermeable layer is being broken or field drains have been installed prior to the operation. Otherwise it will not have any long-term effect and may do more harm than good. • Most land drainage systems are poorly maintained. Open drains should be clean and as deep as possible and field drains feeding into them should be regularly rodded or jetted.
    • Land Spreading of Animal Manures, Farm Wastes & Non-Agricultural Organic Wastes. Part 1 manure (and other organic wastes) management guidelines for intensive agricultural enterprises.

      Carton, Owen T.; Magette, William L. (Teagasc, 1999-05-01)
      The objective of the Teagasc Manure (and Other Organic Wastes) Management Guidelines for IAE are to provide an operational framework for the agronomically efficient and environmentally safe recycling of these organic by-products, maximising the benefits of nutrients they contain at minimum cost. The principles of the approach are equally applicable to the management of all manures and organic wastes applied to land. The approach includes programmes for controlling manure quantity and quality; operational procedures covering storage, transport and nutrient management; and a quality assurance programme. These Guidelines assign the importance of manure management on an equal footing with other production practices. Implementation of these Guidelines may entail higher costs c o m p a red with traditional practices. However, some of the benefits accruing from the improved management practices can partly or wholly offset the costs of implementation.
    • Landscape aesthetics: Assessing the general publics’ rural landscape preferences

      Howley, Peter (Teagasc, Oak Park, Carlow, Ireland, 2011)
      The central aim of this study was to gain greater insights into the factors that affect individuals’ preferences for a variety of landscape settings. To achieve this aim, this paper derived dependent variables (based on a factor analysis of respondents mean ratings of 47 landscape images) representing 5 different landscape categories. These variables were then utilized in separate OLS regression models to examine the effect of personal characteristics, residential location and environmental value orientations on landscape preferences. First in terms of visual amenity the results suggest that the general public have the strongest preference for landscapes with water related features as its dominant attribute which was followed by cultural landscapes. Second the results also demonstrate how there is significant heterogeneity in landscape preferences as both personal characteristics and environmental value orientations were found to strongly influence preferences for all the landscape types examined. Moreover the effect of these variables often differed significantly across the various landscape groupings. In terms of land use policy, given the diversity of preferences a one size fits all approach will not meet the general publics’ needs and desires.
    • Leaching of N compounds from swards used for dairying that are N based and irrigated with dirty water/slurry.

      Richards, K.; Ryan, M.; Coxon, C. (Teagasc, 1998-12-01)
      A study was carried out to investigate nitrate leaching on a dairy farm in Co. Cork. The farm had a history of high nitrate-N in borehole waters and the study aimed to elucidate the causative factors for this. Physical and chemical data regarding the soils, the hydrology, and the N input/output balances were determined and collated. Results showed that nitrate-N concentrations > the EU maximum allowable concentration (MAC) of 11.3 mg/l for drinking water occurred in soil drainage from the light textured soils studied due to a large imbalance between N inputs and outputs. High fertiliser N usage, animal manure and dirty water applications, atmospheric N depositions and soil organic N mineralisation in combination produced these results . While it is recognised that nitrate leaching will vary in amount from year to year the lessons from the study are clear - light textured soils that are used for intensive dairying and which receive high inputs of N are prone to release drainage water high in nitrate.
    • Leaching Studies in Lysimeter Units.

      Ryan, M.; Fanning, A. (Teagasc, 1999-09-01)
      Lysimeter studies have shown the adverse effect of Fallow soil in releasing NO3-N to soil drainage water. A soil at Johnstown Castle under Fallow management gave mean NO3-N drainage water concentrations >MAC (maximum admissible concentration, 11.3 mg/l) in the 10 th , 11 th , 12 th and 13 th years of cultivation. In the 14 t h year this changed as the Fallow treatment showed a mean value <MAC, indicating reduced N mineralisation. However, 7 of that year's 13 water samples were > MAC. On the same soil, barley receiving 120 kg N/ha fertiliser N, showed variable results - soil drainage water concentrations were <MAC in one year but >MAC in another year; the mean values were < the Guide Level (MAC÷2) in both years. When the fertiliser input was raised to 180 kg N/ha, MAC was breached in both sampling years and the mean value was > the Guide Level. Winter wheat receiving 150 kg N/ha as fertiliser had all soil drainage water concentrations <MAC in one year but two samples breached MAC in another year. The mean values were < the Guide Level in both years. On application of 200 kg N/ha, MAC was breached in both years and mean annual NO3- N concentrations were < the Guide Level or > the Guide Level, depending on drainage water volume. These results apply to a soil in cultivation since 1985 having reduced organic N reserves. Higher NO3-N concentrations in soil drainage water would be expected with similar soils recently changed from grass to arable farming. On grassed lysimeters (Johnstown Castle soil), that had been growing barley for 10 years, a combination of 300 kg/ha fertiliser N with 126 kg/ha cattle slurry N, applied in December or February and the same amount of fertiliser N plus 120 kg/ha pig slurry N, applied in December or February gave soil drainage water samples that only breached MAC once in 12 samplings per treatment. The mean NO3-N concentrations were < the Guide Level. A slightly lower mean N (118 kg/ha) input via the slurries plus the same amount of fertiliser N gave lower NO 3- N concentrations for all treatments except the pig slurry (+ fertiliser) applied in November. This treatment breached MAC twice and resulted in a mean NO3-N concentration > the Guide Level. Cultivating the soil, in order to re-sow grass, produced a large release of organic N via mineralisation and this combined with a small fertiliser N input (50 kg/ha) gave very high concentrations of NO3-N in the drainage water. A delay in sowing from June to the end of September exacerbated this problem. The final phase of experimentation showed very low levels of NO3- N in the drainage water which was primarily induced by decreasing fertiliser N input to 200 kg/ha and slurry N input to 50 kg/ha. Five soils, representative of major Irish soils, were subjected to lysimeter trials in a similar manner under grass. In the first experiment the soils received 300 kg/ha fertiliser N plus approximately 120 kg N/ha as pig or cattle slurry. In Years 1, 2, when mean values were pooled over treatments, MAC was breached 2, 3 times by Clonroche; 5, 3 times by Elton, 1, 2 times by Oakpark; 5 times and once by Rathangan soil drainage water. Applying cattle or pig slurry in December with fertiliser N, applied during the growing season, gave the highest number of water samples in breach of MAC. Reducing the fertiliser N to 200 kg/ha and the slurry N to 51 kg/ha drastically lowered the NO3-N concentrations in the drainage water to sustainable levels. Cultivation followed by Fallow for 3 months prior to sowing grass gave very high NO3-N concentrations in all soil drainage waters. Due to recycling of N via animal excreta, greater leaching of NO3- N is likely to occur on grazed grass receiving identical N inputs.
    • Linking hydrogeochemistry to nitrate abundance in groundwater in agricultural settings in Ireland

      Jahangir, Mohammad M. R.; Johnston, P.; Khalil, M.I.; Richards, Karl G. (Elsevier, 2012-05-11)
      Nitrate (NO3-–N) contamination of groundwater and associated surface waters is an increasingly important global issue with multiple impacts on terrestrial, aquatic and atmospheric environments. Investigation of the distribution of hydrogeochemical variables and their connection with the occurrence of NO3-–N provides better insights into the prediction of the environmental risk associated with nitrogen use within agricultural systems. The research objective was to evaluate the effect of hydrogeological setting on agriculturally derived groundwater NO3-–N occurrence. Piezometers (n = 36) were installed at three depths across four contrasting agricultural research sites. Groundwater was sampled monthly for chemistry and dissolved gases, between February 2009 and January 2011. Mean groundwater NO3-–N ranged 0.7–14.6 mg L−1, with site and groundwater depth being statistically significant (p < 0.001). Unsaturated zone thickness and saturated hydraulic conductivity (Ksat) were significantly correlated with dissolved oxygen (DO) and redox potential (Eh) across sites. Groundwater NO3-–N occurrence was significantly negatively related to DOC and methane and positively related with Eh and Ksat. Reduction of NO3-–N started at Eh potentials <150 mV while significant nitrate reduction occurred <100 mV. Indications of heterotrophic and autotrophic denitrification were observed through elevated dissolved organic carbon (DOC) and oxidation of metal bound sulphur, as indicated by sulphate (SO42-). Land application of waste water created denitrification hot spots due to high DOC losses. Hydrogeological settings significantly influenced groundwater nitrate occurrence and suggested denitrification as the main control.
    • Listeria monocytogenes in Milk Products

      Jordan, Kieran; Hunt, Karen; Dalmasso, Marion (Springer International Publishing, 2016-04-13)
      Milk and milk products are frequently identified as vectors for transmission of Listeria monocytogenes. Milk can be contaminated at farm level either by indirect external contamination from the farm environment or less frequently by direct contamination of the milk from infection in the animal. Pasteurisation of milk will kill L. monocytogenes, but post-pasteurisation contamination, consumption of unpasteurised milk and manufacture of unpasteurised milk products can lead to milk being the cause of outbreaks of listeriosis. Therefore, there is a concern that L. monocytogenes in milk could lead to a public health risk. To protect against this risk, there is a need for awareness surrounding the issues, hygienic practices to reduce the risk and adequate sampling and analysis to verify that the risk is controlled. This review will highlight the issues surrounding L. monocytogenes in milk and milk products, including possible control measures. It will therefore create awareness about L. monocytogenes, contributing to protection of public health.
    • Listeriolysin S, a Novel Peptide Haemolysin Associated with a Subset of Lineage I Listeria monocytogenes

      Cotter, Paul D.; Draper, Lorraine A.; Lawton, Elaine M.; Daly, Karen M.; Groeger, David S.; Casey, Patrick G.; Ross, R. Paul; Hill, Colin (PLOS, 2008-09-12)
      Streptolysin S (SLS) is a bacteriocin-like haemolytic and cytotoxic virulence factor that plays a key role in the virulence of Group A Streptococcus (GAS), the causative agent of pharyngitis, impetigo, necrotizing fasciitis and streptococcal toxic shock syndrome. Although it has long been thought that SLS and related peptides are produced by GAS and related streptococci only, there is evidence to suggest that a number of the most notorious Gram-positive pathogenic bacteria, including Listeria monocytogenes, Clostridium botulinum and Staphylococcus aureus, produce related peptides. The distribution of the L. monocytogenes cluster is particularly noteworthy in that it is found exclusively among a subset of lineage I strains; i.e., those responsible for the majority of outbreaks of listeriosis. Expression of these genes results in the production of a haemolytic and cytotoxic factor, designated Listeriolysin S, which contributes to virulence of the pathogen as assessed by murine- and human polymorphonuclear neutrophil–based studies. Thus, in the process of establishing the existence of an extended family of SLS-like modified virulence peptides (MVPs), the genetic basis for the enhanced virulence of a proportion of lineage I L. monocytogenes may have been revealed.
    • Live animal measurements, carcass composition and plasma hormone and metabolite concentrations in male progeny of sires differing in genetic merit for beef production

      Clarke, A. M.; Drennan, Michael J; McGee, Mark; Kenny, David A.; Evans, Ross D; Berry, Donagh P. (Cambridge University Press, 2009-07)
      In genetic improvement programmes for beef cattle, the effect of selecting for a given trait or index on other economically important traits, or their predictors, must be quantified to ensure no deleterious consequential effects go unnoticed. The objective was to compare live animal measurements, carcass composition and plasma hormone and metabolite concentrations of male progeny of sires selected on an economic index in Ireland. This beef carcass index (BCI) is expressed in euros and based on weaning weight, feed intake, carcass weight and carcass conformation and fat scores. The index is used to aid in the genetic comparison of animals for the expected profitability of their progeny at slaughter. A total of 107 progeny from beef sires of high (n = 11) or low (n = 11) genetic merit for the BCI were compared in either a bull (slaughtered at 16 months of age) or steer (slaughtered at 24 months of age) production system, following purchase after weaning (8 months of age) from commercial beef herds. Data were analysed as a 2 × 2 factorial design (two levels of genetic merit by two production systems). Progeny of high BCI sires had heavier carcasses, greater (P < 0.01) muscularity scores after weaning, greater (P < 0.05) skeletal scores and scanned muscle depth pre-slaughter, higher (P < 0.05) plasma insulin concentrations and greater (P < 0.01) animal value (obtained by multiplying carcass weight by carcass value, which was based on the weight of meat in each cut by its commercial value) than progeny of low BCI sires. Regression of progeny performance on sire genetic merit was also undertaken across the entire data set. In steers, the effect of BCI on carcass meat proportion, calculated carcass value (c/kg) and animal value was positive (P < 0.01), while a negative association was observed for scanned fat depth pre-slaughter and carcass fat proportion (P < 0.01), but there was no effect in bulls. The effect of sire expected progeny difference (EPD) for carcass weight followed the same trends as BCI. Muscularity scores, carcass meat proportion and calculated carcass value increased, whereas scanned fat depth, carcass fat and bone proportions decreased with increasing sire EPD for conformation score. The opposite association was observed for sire EPD for fat score. Results from this study show that selection using the BCI had positive effects on live animal muscularity, carcass meat proportion, proportions of high-value cuts and carcass value in steer progeny, which are desirable traits in beef production.
    • Long-Term Persistence and Leaching of Escherichia coli in Temperate Maritime Soils

      Brennan, Fiona P.; O'Flaherty, Vincent; Kramers, Gaelene; Grant, Jim; Richards, Karl G. (American Society for Microbiology, 2009-12)
      Enteropathogen contamination of groundwater, including potable water sources, is a global concern. The spreading on land of animal slurries and manures, which can contain a broad range of pathogenic microorganisms, is considered a major contributor to this contamination. Some of the pathogenic microorganisms applied to soil have been observed to leach through the soil into groundwater, which poses a risk to public health. There is a critical need, therefore, for characterization of pathogen movement through the vadose zone for assessment of the risk to groundwater quality due to agricultural activities. A lysimeter experiment was performed to investigate the effect of soil type and condition on the fate and transport of potential bacterial pathogens, using Escherichia coli as a marker, in four Irish soils (n 9). Cattle slurry (34 tonnes per ha) was spread on intact soil monoliths (depth, 1 m; diameter, 0.6 m) in the spring and summer. No effect of treatment or the initial soil moisture on the E. coli that leached from the soil was observed. Leaching of E. coli was observed predominantly from one soil type (average, 1.11 0.77 CFU ml 1), a poorly drained Luvic Stagnosol, under natural rainfall conditions, and preferential flow was an important transport mechanism. E. coli was found to have persisted in control soils for more than 9 years, indicating that autochthonous E. coli populations are capable of becoming naturalized in the low-temperature environments of temperate maritime soils and that they can move through soil. This may compromise the use of E. coli as an indicator of fecal pollution of waters in these regions.