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Long-term mineral fertilizer application strongly influences soil microbial community structure but not diversity.
No full textMineral fertilizer application is a common management practice in grassland production. However, its
potential long-term influence on soil microbial communities requires further study. In 1972, a split-plot
experiment was established in the Jura region of Switzerland containing a non-fertilized control and a
fertilized treatment of 150, 80 and 240 kg ha-1 yr-1 mineral N, P and K, respectively. Soil samples for
microbial community analysis were taken in the summer of 2018. There was a highly significant effect
of mineral fertilizer application on both soil fungal and bacterial community structure (all P<0.001),
with unique fungal and bacterial indicator OTU (operational taxonomic unit) being associated to each
treatment. Contrastingly, alpha diversity measures (OTU richness and inverse Simpson index) were not
affected (P>0.05). These results demonstrated that long-term mineral fertilizer application had a strong
influence on soil microbial community structure, promoting different microbial taxa, but did not affect
the overall alpha diversity of these communities
Development and validation of a quantitative method for 15 antiviral drugs in poultry muscle using liquid chromatography coupled to tandem mass spectrometry
Get PDFpeer-reviewedThe objective of this work was to develop a quantitative multi-residue method for analysing antiviral drug residues and their metabolites in poultry meat samples. Antiviral drugs are not licensed for the treatment of influenza in food producing animals. However, there have been some reports indicating their illegal use in poultry. In this study, a method was developed for the analysis of 15 antiviral drug residues in poultry muscle (chicken, duck, quail and turkey) using liquid chromatography coupled to tandem mass spectrometry. This included 13 drugs against influenza and associated metabolites, but also two drugs employed for the treatment of herpes (acyclovir and ganciclovir). The method required the development of a novel chromatographic separation using a hydrophilic interaction chromatographic (HILIC) BEH amide column, which was necessary to retain the highly polar compounds. The analytes were detected using a triple quadrupole mass spectrometer operating in positive electrospray ionization mode. A range of different sample preparation protocols suitable for polar compounds were evaluated. The most effective procedure was based on a simple acetonitrile-based protein precipitation step followed by a further dilution in a methanol/water solution. The confirmatory method was validated according to the EU 2021/808 guidelines on different species including chicken, duck, turkey and quail. The validation was performed using various calibration curves ranging from 0.1 µg kg−1to 200 µg kg−1, according to the analyte. Depending on the analyte sensitivity, decision limits achieved ranged from 0.12 µg kg−1 for arbidol to 34.7 µg kg−1 for ribavirin. Overall, the reproducibility precision values ranged from 2.8% to 22.7% and the recoveries from 84% to 127%. The method was applied to 120 commercial poultry samples from the Irish market, which were all found to be residue-free
Identification and distribution of leatherjackets (Tipula spp.) in the Republic of Ireland
Get PDFpeer-reviewedThe soil-dwelling larval stage of crane flies, commonly known as leatherjackets, are classified as agricultural pests in Europe, and pests of turf in North America and Canada. They cause significant damage and yield loss in many cropping systems through their feeding on plant roots and stems at ground level. The effective chemical control for these pests, chlorpyrifos (available since 1965), was prohibited across Europe in 2019. This has left severely restricted control options for growers. Unlike Northern Ireland and Great Britain, no leatherjacket surveys or routine identifications have been conducted across Ireland. Therefore, the leatherjacket species of agronomic importance has not been confirmed. Since lifecycles, feeding behaviour and damage periods differ between species, identifying the most common species is a vital first step in any pest management strategy. Here we report key findings from a 2-yr structured survey of Irish crops, conducted in 2019 and 2021, where 135 sites were sampled. Both grassland and cereal crops were inspected. Soil cores and soil samples were collected and larval abundance determined. The European crane fly, Tipula paludosa Meigen, accounted for approximately 70% of larvae collected and identified (n = 337). In 2019, 40% of grasslands exceeded the threshold of 1 million larvae/ha, while only 3.3% of cereal fields were over the threshold of 600,000 larvae/ha. These results indicate that agricultural grasslands in Ireland have the potential to be significantly impacted by leatherjacket damage, although this may vary temporally and geographically across the island. Without effective control options, yield losses will be highly probable
A note on current pyrethroid susceptibility in the bird cherry-oat aphid Rhopalosiphum padi in Ireland
Get PDFpeer-reviewedThe objective of this study was to observe the response of the bird cherry oat aphid, Rhopalosiphum padi (Linnaeus, 1758) to field rate equivalents of insecticides, by using bioassays of vials coated with the pyrethroid, λ-cyhalothrin. The results from the geographically separated Irish R. padi colonies indicated a susceptible response, which was a similar finding to the UK which showed sensitivity in this species of cereal aphids. Monitoring the susceptibility status of aphids using bioassays gives information regarding developments of any tolerance, which could be a precursor, or resistance against the target chemical insecticide, which is an important integrated pest management tool
Linear type trait genetic trends in Irish Holstein-Friesian dairy animals
Get PDFpeer-reviewedThe objective of the present study was to investigate the genetic trends of 18 subjectively scored linear type traits describing animal morphology, as well as udder, teat, feet and leg conformation. The analysis was undertaken using 2,932,700 Holstein-Friesian females born in the Republic of Ireland between the years 2000 and 2020, inclusive. The results indicate that Holstein-Friesian females have progressively become shorter in stature as well as shallower (i.e. body depth) and less angular. The reduction in genetic merit for stature score since the year 2004 was, however, only observed in non-herdbook-registered heifers. Furthermore, the reducing score in body depth (i.e. narrower) and angularity (i.e. less angular) was approximately twice as fast in non-herdbook-registered heifers as it was in herdbook-registered heifers. Differences in the genetic merit of the body-related traits for calves born versus those that became cows only existed prior to 2010 with little biological differences thereafter; this observation was common across most of the linear type traits. Genetic merit for locomotion in non-herdbook-registered animals has deteriorated over the 20-yr period, while the foot angle over that period is becoming lower; no such trends were observed for the herdbook-registered animals. Large differences not only in the trends themselves, but also in the mean genetic merit for udder traits existed when comparing herdbook-registered calves versus non-registered calves. In conclusion, genetic merit for many of the traits evaluated has trended relatively consistent in a given direction, albeit the cumulative change in genetic s.d. units per traits over the 20-yr period was very small
Nitrous oxide emission factors from an intensively grazed temperate grassland: A comparison of cumulative emissions determined by eddy covariance and static chamber methods
Get PDFpeer-reviewedQuantifying nitrous oxide (N2O) emissions from grazed pastures can be problematic due to the presence of hotspots and hot moments of N2O from animal excreta and synthetic fertilisers. In this study, we quantified field scale N2O emissions from a temperate grassland under a rotational grazing management using eddy covariance (EC) and static chamber techniques. Measurements of N2O by static chambers were made for four out of nine grazing events for a control, calcium ammonium nitrate (CAN), synthetic urine (SU) + CAN and dung + CAN treatments. Static chamber N2O flux measurements were upscaled to the field scale (FCH FIELD) using site specific emission factors (EF) for CAN, SU+CAN and dung + CAN. Mean N2O EFs were greatest from the CAN treatment while dung + CAN and SU + CAN emitted similar N2O-N emissions. Cumulative N2O-N emissions over the study period measured by FCH FIELD measurements were lower than gap-filled EC measurements. Emission factors of N2O from grazing calculated by FCH FIELD and gap-filled were 0.72% and 0.96%, respectively. N2O-N emissions were derived mainly from animal excreta (dung and urine) contributing 50% while N2O-N losses from CAN and background accounted for 36% and 14%, respectively. The study highlights the advantage of using both the EC and static chamber techniques in tandem to better quantify both total N2O-N losses from grazed pastures while also constraining the contribution of individual N sources. The EC technique was most accurate in quantifying N2O emissions, showing a range of uncertainty that was seven times lower relative to that attributed to static chamber measurements, due to the small chamber sample size per treatment and highly variable N2O flux measurements over space and time
Are subjectively scored linear type traits suitable predictors of the genetic merit for feed intake in grazing Holstein-Friesian dairy cows?
Get PDFpeer-reviewedMeasuring dry matter intake (DMI) in grazing dairy cows using currently available techniques is invasive, time consuming, and expensive. An alternative to directly measuring DMI for use in genetic evaluations is to identify a set of readily available animal features that can be used in a multitrait genetic evaluation for DMI. The objectives of the present study were thus to estimate the genetic correlations between readily available body-related linear type traits and DMI in grazing lactating Holstein-Friesian cows, but importantly also estimate the partial genetic correlations between these linear traits and DMI, after adjusting for differences in genetic merit for body weight. Also of interest was whether the predictive ability derived from the estimated genetic correlations materialized upon validation. After edits, a total of 8,055 test-day records of DMI, body weight, and milk yield from 1,331 Holstein-Friesian cows were available, as were chest width, body depth, and stature from 47,141 first lactation Holstein-Friesian cows. In addition to considering the routinely recorded linear type traits individually, novel composite traits were defined as the product of the linear type traits as an approximation of rumen volume. All linear type traits were moderately heritable, with heritability estimates ranging from 0.27 (standard error = 0.14) to 0.49 (standard error = 0.15); furthermore, all linear type traits were genetically correlated (0.29 to 0.63, standard error 0.14 to 0.12) with DMI. The genetic correlations between the individual linear type traits and DMI, when adjusted for genetic differences in body weight, varied from −0.51 (stature) to 0.48 (chest width). These genetic correlations between DMI and linear type traits suggest linear type traits may be useful predictors of DMI, even when body weight information is available. Nonetheless, estimated genetic merit of DMI derived from a multitrait genetic evaluation of linear type traits did not correlate strongly with actual DMI in a set of validation animals; the benefit was even less if body weight data were also available
Invited review: Review of taxonomic changes in dairy-related lactobacilli
Get PDFpeer-reviewedThe genus Lactobacillus has represented an extremely large and diverse collection of bacteria that populate a wide range of habitats, and which may have industrial applications. Researchers have grappled with the immense genetic, metabolic, and ecological diversity within the genus Lactobacillus for many years. As a result, the taxonomy of lactobacilli has been extensively revised, incorporating new genus names for many lactobacilli based on their characteristics including genomic similarities. As a result, many lactobacilli traditionally associated with dairy products now have new genus names and are grouped into new clades or clusters of species. In this review, we examine how the taxonomic restructuring of the genus Lactobacillus will affect the dairy industry and discuss lactobacilli associated with dairy production, processing, and those that confer possible health benefits when delivered by dairy products
Faecal near-infrared reflectance spectroscopy profiling for the prediction of dietary nutritional characteristics for equines
Get PDFpeer-reviewedFaecal near infrared reflectance spectroscopy (NIRS) profiling involves the use of NIRS for the prediction of nutrient components of animal diets from their faecal samples. This study evaluated the potential use of faecal NIRS profiling for the prediction of minerals, fibre fractions, and organic matter (OM) in horses’ diet. Two feeding trials were conducted consisting of 29 horses housed in individual stables and fed unique diets (D) to obtain diet reference data and faecal (F) NIR spectra (D:F) pairs. The D:F pairs were used for the development of faecal NIRS predictive equations. The trials ran for a total of five weeks (7 days adaptation and 4 weeks of measurement). Diets were adjusted weekly by changing the forage and concentrate supplied to include variation in the diet. Faecal and diet samples were pooled per week per horse resulting in 116 D:F pairs (29 horses x 4 weeks). Samples from weeks 1–3 (n = 87) were used to develop calibration and week 4 samples were used as an independent validation set (n = 29). Modified partial least square regression was used for calibration development. Results obtained showed that faecal NIRS prediction of dietary OM was excellent [coefficient of determination of validation (R2val) = 0.92 and ratio performance deviation (RPD) = 3.54], while that of neutral detergent fibre (aNDF) was very good (R2val and RPD: 0.83 and 2.12). The validation statistics (R2val: 0.77 and RPD: 1.56) showed the prediction model for acid detergent fibre (ADF) was acceptable but not as precise as those of OM and aNDF. Prediction of acid detergent lignin (ADL) was the poorest (R2val = 0.41and RPD = 1.05). For the mineral components, prediction of copper (Cu) was very good (R2val = 0.81, RPD= 2.11) and better than those of Phosphorus (P), Sulphur (S) and Manganese (Mn) which all had R2val of 0.60–0.67 and RPD of 1.60–1.64. Overall, this study showed that faecal NIRS profiling can be used to successfully predict OM, aNDF and Cu concentration in horses’ diet. Although, the predictions of other fibre fractions were less satisfactory, faecal NIRS can still be used for monitoring purposes and improved for future application to independent samples
Environmental and cultivar variability in composition, content and biological activity of phenolic acids and alkylresorcinols of winter wheat grains from a multi-site field trial across Europe
Get PDFpeer-reviewedDifferent factors such as the genotype, environmental conditions, temperature stress, solar radiation and others can influence the phytochemical status of plants. The concentration of phenolic acids and alkylresorciols (ARs) as well as their chemical composition and biological activity have been determined in twelve winter wheat cultivars grown at eight European locations. This was the first winter wheat multi-location field trial of the European Consortium for Open Field Experimentation (ECOFE). Extracts from grain were analyzed using a UPLC-PDA-ESI-MS system (phenolic acids), UPLC-PDA-MS/MS (alkylresorcinols) and TLC-DPPH• test with ImageJ program (antiradical activity). The phenolic acid profile consisted of five hydroxybenzoic acid and four hydroxycinnamic acid derivatives, among which ferulic and sinapic acids were predominated. The ARs profile consisted of nine AR derivatives, among which 5-n-heneicosylresorcinol (C21:0) and 5-n-nonadecanylresorcinol (C19:0) were predominated. Our study showed significant differences in phenolic acids and AR content between wheat cultivars, as well as between locations. We observed a positive correlation between the biological activity of extracts and the total amount of phenolic acids and ARs. Two cultivars, Chambo and Julius (average of all sites) and samples from the Spanish site (average of all cultivars) showed the highest content and composition of nutritional substances