Recent Submissions

  • Evolution of the fatty acid composition and oxidative stability of Merino lamb meat stored under different modified atmospheres

    Gutierrez, J. I.; Tejeda, J. F.; Parra, V.; Andres, A. I. (Teagasc (Agriculture and Food Development Authority), Ireland, 2013)
    The effect of four different gas mixtures on the evolution of the fatty acid composition of neutral lipids and polar lipids, and oxidative stability of Merino fresh lamb meat was studied. Merino fresh lamb meat was packed under four different atmospheres (Atmosphere 1: Air; Atmosphere 2: 70% O2 + 30% CO2; Atmosphere 3: 80% O2 + 20% CO2; and Atmosphere 4: 30% CO2 + 69.6% Ar + 0.4% CO) and stored under refrigeration (3±1 °C) for 12 days. Time of storage only affected the proportions of saturated fatty acids of neutral lipids (P<0.05). There were no significant differences among gas mixtures for the fatty acid profile of neutral and polar lipids during storage (P>0.05). Malondialdehyde and hexanal concentrations were higher for the atmospheres with the highest proportion of oxygen (Atmospheres 2 and 3) indicating lower oxidative stability. The atmosphere consisting of 30% CO2 + 69.6% Ar + 0.4% CO is recommended, due to a higher oxidative stability of meat during refrigerated storage.
  • How much grassland biomass is available in Ireland in excess of livestock requirements?

    McEniry, Joseph; Crosson, Paul; Finneran, Eoghan; McGee, Mark; Keady, Tim; O'Kiely, Padraig (Teagasc (Agriculture and Food Development Authority), Ireland, 2013)
    Grassland is a dominant biomass resource in Ireland and underpins most animal production systems. However, other commercial uses for grassland biomass exist, including, for example, the production of biogas through anaerobic digestion for the generation of heat, electricity and transport fuel. The objective of this study was to estimate the annual grassland resource available in Ireland in excess of livestock requirements under six contrasting scenarios. Under current grassland management and production practices there is an estimated average annual grassland resource of ca. 1.7 million tonnes of dry matter (DM) available in excess of livestock requirements. Only a small proportion of this resource (0.39 million tonnes of DM per annum) would be available if the targets set out in ‘Food Harvest 2020’ were achieved. However, increasing nitrogen (N) fertiliser input (to the limit permitted by the E.U. Nitrates Directive) combined with increasing the grazed grass utilisation rate of cattle (from 0.60 to 0.80 kg DM ingested by livestock per kg DM grown) has the potential to significantly increase this average resource to 12.2 million t DM/annum, even when allowing for achievement of ‘Food Harvest 2020’ targets. Under these scenarios, alternative uses for grassland biomass such as anaerobic digestion and green biorefining would not compete with traditional dairy, beef and lamb production systems, but could provide an alternative enterprise and income to farmers.
  • Optimisation of hydrolysis conditions for antioxidant hydrolysate production from whey protein isolates using response surface methodology

    Zhidong, L.; Benheng, G.; Xuezhong, C.; Zhenmin, L.; Yun, D.; Hongliang, H.; Wen, R. (Teagasc (Agriculture and Food Development Authority), Ireland, 2013)
    The hydrolysates of whey protein isolates (WPI) by papain were found to possess antioxidant activity. Response surface methodology (RSM) was used to improve the antioxidant activity of these hydrolysates. The model was validated and shown to be statistically adequate and accurate in predicting the response. For both 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activity and reducing power responses, the optimised conditions were achieved at an enzyme to substrate ratio (E/S, w/w) of 2.22%, hydrolysis time of 3.60 h, and hydrolysis temperature of 45.70 °C. Under the optimised conditions, DPPH radical-scavenging activity of the hydrolysates of WPI was 31.48% and the reducing power was 0.612 at 700 nm. The results of confirmation experiments indicated that the model was powerful and suitable for estimation of the experimental value. The hydrolysate of WPI has potential application as an antioxidant in food products.
  • The health status of Irish honeybee colonies in 2006

    Coffey, M. F.; Barth, Susanne; Hayes, K.; Breen, James (Teagasc (Agriculture and Food Development Authority), Ireland, 2013)
    This study assessed the health status of Irish honeybee colonies and provides a snapshot of the incidence of a number of important colony parasites/pathogens including: the mite Varroa destructor; three associated viruses (deformed wing virus (DWV), acute bee paralysis virus (ABPV) and Kashmir virus (KBV)); the tracheal mite Acarapis woodi; the microsporidian Nosema spp., and the insect Braula coeca. During June/July 2006, 135 samples of adult bees were collected from productive colonies throughout Ireland and standard techniques were used to determine the presence and absence of the parasites and pathogens. Varroa destructor was positively identified in 72.6% of the samples and was widely distributed. Although the samples were analysed for three viruses, DWV, ABPV and KBV, only DWV was detected (frequency = 12.5%). Acarapis woodi and Nosema spp. occurred in approximately 11% and 22% of the samples, respectively, while B. coeca, a wingless dipteran that was once common in Irish honeybee colonies, was very rare (3.7%). Samples where all the pathogens/parasites were jointly absent were statistically under-represented in Leinster and DWV was statistically over-represented in Munster. In Ulster, there was over-representation of the categories where all parasites/pathogens were jointly absent and for A. woodi, and underrepresentation of V. destructor.
  • Seasonality of nitrogen uptake, apparent recovery of fertilizer nitrogen and background nitrogen supply in two Irish grassland soils

    Murphy, P. N. C.; O'Connell, K.; Watson, S.; Watson, C. J.; Humphreys, James (Teagasc (Agriculture and Food Development Authority), Ireland, 2013)
    Improving fertilizer nitrogen (N) use efficiency is central to sustainable and profitable grassland agriculture. A plot experiment with a control and fertilizer N (calcium ammonium nitrate, 25–50 kg/ha N) applied on nine occasions from February to September 2002 was conducted at two sites in southwest Ireland to assess N uptake and apparent recovery of fertilizer N (ARFN). Apparent recovery of fertilizer N after eight weeks varied from low in February (21%) and March (46%) to high from April to August (69–98%), indicating that high N use efficiency can be achieved in Irish grasslands at these times. Low recovery in spring suggested that N was applied in excess of immediate crop requirements. Note that N uptake and ARFN values from this study are likely to be somewhat conservative, particularly for spring applications. Over the 8 weeks during which growth was monitored, most (70%) of the grass yield and N uptake response to fertilizer N were in weeks 1 to 4 after application; however, a significant (30%) response occurred in weeks 5–8. This suggested that residual N availability following grazing at 4 weeks can be significant and that there may be scope to decrease N application rates in a grazing rotation. This can potentially improve N use efficiency and decrease N surpluses, with associated economic and environmental benefits. Apparent recovery of fertilizer N was closely related to soil temperature, with a 5.8% increase in ARFN with a 1 °C increase in temperature. Background (non-fertilizer) N supply contributed an average of 164 kg/ha per year (49%) taken up by the fertilized sward, highlighting the potential importance of soil N mineralisation to grassland productivity. Note that these results are for one year at two sites and that conditions may vary between years and at other sites and also that the experiment did not reproduce the cumulative effect of repeated fertilizer application over the grazing year.
  • Process environment sampling can help to reduce the occurrence of Listeria monocytogenes in food processing facilities

    Dalmasso, Marion; Jordan, Kieran (Teagasc (Agriculture and Food Development Authority), Ireland, 2013)
    The occurrence and persistence of Listeria monocytogenes strains in food processing environments pose a risk of cross-contamination to food. The control of these strains is thus essential to ensure food safety. In the present study, 205 samples were collected from a food processing facility between May 2012 to February 2013 and analysed for the presence of L. monocytogenes by the ISO11290 standard method. L. monocytogenes isolates were differentiated using pulsed field gel electrophoresis. Up to 55% of the samples were positive for L. monocytogenes until October 2012. Advice was given on the implementation of corrective actions regarding cleaning and disinfection procedures and workflows. This resulted in a decrease in the number of positive samples, reflecting the reduction of L. monocytogenes in the processing environment. Eight pulsotypes were found in the food processing facility environment, mainly on non-food contact surfaces. One type was identified as persistent as it was isolated on each sampling occasion and constituted more than 71% of the isolates collected. It was the only type found in the processing environment after the implementation of corrective actions. This work demonstrates that processing environment sampling plans are effective to assess hygiene and implement corrective actions. This contributes to prevention of contamination events and consequently to assuring the safety of the food product.
  • Genetics of reproductive performance in seasonal calving dairy cattle production systems

    Berry, Donagh P.; Kearney, J. F.; Twomey, K.; Evans, R. D. (Teagasc (Agriculture and Food Development Authority), Ireland, 2013)
    Profitable seasonal calving dairy production systems require a cow that will establish pregnancy early in the breeding season implying a quick return to service post-calving and good pregnancy rates. Genetic selection provides an opportunity to achieve this goal so therefore the objective of this study was to estimate the necessary genetic parameters for fertility traits, pertinent to seasonal calving herds, in order to facilitate genetic selection for fertility. The data, following editing, consisted of parity 1 to 3 records on up to 397,373 Holstein-Friesian dairy cows in Ireland. Variance components for the defined interval fertility traits (age at first calving, calving to first service interval, calving interval), binary fertility traits (submission rate in the first 21 days of the breeding season, pregnant to first service, pregnant in the first 42 days of the breeding season, calved in the first 42 days of the calving season) and the count fertility trait (number of services) were estimated using univariate animal models and covariances among traits were estimated using bivariate sire models. Heritability estimates of the nine fertility traits (including age at first calving and survival) varied from 0.01 to 0.07 within parity one to three. The coefficient of genetic variation for the fertility traits varied from 3.3% to 15.3%. Calving to first service interval, within parity, was moderately positively genetically correlated (0.54 to 0.75) with calving interval and was, in general, moderately negatively correlated with both submission rate (-0.68 to -0.29) and pregnant in the first 42 days of the breeding season (-0.36 to -0.14). Calving interval was moderately positively correlated (0.24 to 0.68) with number of services. Irrespective of parity, the genetic correlations between calving interval with calving in the first 42 days of the calving season, and submission rate with pregnant in the first 42 days of the breeding season were all negative. The genetic correlations among calving in the first 42 days of the calving season, submission rate and pregnant in the first 42 days of the breeding season were all positive. All fertility traits were generally antagonistically genetically correlated with lactation milk yield, but most were moderate to strongly favourably correlated with survival to the next lactation. This study provides the necessary genetic parameters to undertake national genetic evaluations for fertility to help achieve the fertility targets in seasonal calving herds.