The latest FAD – Faecal antibody detection in cattle:Protocol and results from three UK beef farms naturally infected with gastrointestinal nematodes

Antibodies at gastrointestinal mucosal membranes play a vital role in immunological protection against a range of pathogens, including helminths. Gastrointestinal health is central to efficient livestock production, and such infections cause significant losses. Fecal samples were taken from 114 cattle, across three beef farms, with matched blood samples taken from 22 of those animals. To achieve fecal antibody detection, a novel fecal supernatant was extracted. Fecal supernatant and serum samples were then analysed, using adapted enzyme-linked immunosorbent assay protocols, for levels of total immunoglobulin (Ig)A, IgG, IgM, and Teladorsagia circumcincta-specific IgA, IgG, IgM and IgE (in the absence of reagents for cattle-specific nematode species). Fecal nematode egg counts were conducted on all fecal samples. Assays performed successfully and showed that IgA was the predominant antibody in fecal samples, whereas IgG was predominant in serum. Total IgA in feces and serum correlated within individuals (0.581, P = 0.005), but other Ig types did not. Results support the hypothesis that the tested protocols are an effective method for the non-invasive assessment of cattle immunology. The method could be used as part of animal health assessments, although further work is required to interpret the relationship between results and levels of infection and immunity

Absence of seasonal patterns in MBT-CBT indices in mid-latitude soils

The degree of methylation and cyclization of bacteria-derived branched glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in soils depends on temperature and soil pH. Expressed in the methylation index of branched tetraethers (MBT) and cyclization ratio of branched tetraethers (CBT), these relationships are used to reconstruct past annual mean air temperature (MAT) based on the distribution of branched GDGTs in ancient sediments; the MBT-CBT proxy. Although it was shown that the best correlation of this proxy is with annual MAT, it remains unknown whether a seasonal bias in temperature reconstructions could occur, such as towards a seasonal period of optimal growth’ of the, as yet, unidentified soil bacteria which produce branched GDGTs. To investigate this possibility, soils were sampled from eight different plots in the USA (Minnesota and Ohio), The Netherlands (Texel) and the UK (Devon) in time series over 1 year and analyzed for their branched GDGT content. Further analyses of the branched GDGTs present as core lipids (CLs; the presumed fossil pool) and intact polar lipids (IPLs; the presumed extant pool) were undertaken for two of the investigated soil plots. The amount of IPL-derived branched GDGTs is low relative to the branched GDGT CLs, i.e. only 6–9% of the total branched GDGT pool.In all soils, no clear change was apparent in the distribution of branched GDGT lipids (either core or IPL-derived) with seasonal temperature change; the MBT–CBT temperature proxy gave similar temperature estimates year-round, which generally matched the mean annual soil temperature. In addition to a lack of coherent changes in relative distributions, concentrations of the branched GDGTs did not show clear changes over the seasons. For IPL-derived GDGTs these results suggest that their turnover time in soils is in the order of 1 year or more. Thus, our study does not provide evidence for seasonal effects on the distribution of branched GDGTs in soils, at least at mid-latitudes, and therefore, no direct evidence for a bias of MBT–CBT reconstructed temperatures towards a certain season of optimal growth of the source bacteria. If, however, there is a slight seasonal preference of branched GDGT production, which can easily be obscured by natural variability due to the heterogeneity of soils, then a seasonal bias may potentially still develop over time due to the long turnover time of branched GDGTs

Lactoferrin quantification in cattle faeces by ELISA

Background: Promoting and maintaining health is critical to ruminant welfare and productivity. Within human medicine, faecal lactoferrin is quantified for routine assessment of various gastrointestinal illnesses avoiding the need for blood sampling. This approach might also be adapted and applied for non-invasive health assessments in animals. Methods: In this proof-of-concept study, a bovine lactoferrin enzyme-linked immunosorbent assays (ELISA), designed for serum and milk, was applied to a faecal supernatant to assess its potential for quantifying lactoferrin in the faeces of cattle. Faecal lactoferrin concentrations were compared to background levels to assess the viability of the technique. A comparison was then made against serum lactoferrin levels to determine if they were or were not reflective of one another. Results: The optical densities of faecal samples were significantly greater than background readings, supporting the hypothesis that the assay was effective in quantifying faecal lactoferrin (T13, 115 = 11.99, p < 0.0005). The mean faecal lactoferrin concentration was 0.269 µg mL−1 (S.E. 0.031) and the mean serum concentration 0.074 µg mL−1 (S.E. 0.005). Lactoferrin concentrations of faecal and serum samples, taken from the same animals on the same day, were significantly different (T21 = 2.20, p = 0.039) and did not correlate (r = 0.2699, p = 0.238). Conclusion: Results support the hypothesis that lactoferrin can be quantified in cattle faeces by ELISA. Whilst further research is required to determine the physiological source of the lactoferrin, this highlights the potential of the method for non-invasive assessment of cattle immunology and pathology

Long-term nitrogen addition modifies microbial composition and functions for slow carbon cycling and increased sequestration in tropical forest soil.

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.  Nitrogen (N) deposition is a component of global change that has considerable impact on belowground carbon (C) dynamics. Plant growth stimulation and alterations of fungal community composition and functions are the main mechanisms driving soil C gains following N deposition in N-limited temperate forests. In N-rich tropical forests, however, N deposition generally has minor effects on plant growth; consequently, C storage in soil may strongly depend on the microbial processes that drive litter and soil organic matter decomposition. Here, we investigated how microbial functions in old-growth tropical forest soil responded to 13 years of N addition at four rates: 0 (Control), 50 (Low-N), 100 (Medium-N), and 150 (High-N) kg N ha-1 yr-1 . Soil organic carbon (SOC) content increased under High-N, corresponding to a 33% decrease in CO2 efflux, and reductions in relative abundances of bacteria as well as genes responsible for cellulose and chitin degradation. A 113% increase in N2 O emission was positively correlated with soil acidification and an increase in the relative abundances of denitrification genes (narG and norB). Soil acidification induced by N addition decreased available P concentrations, and was associated with reductions in the relative abundance of phytase. The decreased relative abundance of bacteria and key functional gene groups for C degradation were related to slower SOC decomposition, indicating the key mechanisms driving SOC accumulation in the tropical forest soil subjected to High-N addition. However, changes in microbial functional groups associated with N and P cycling led to coincidentally large increases in N2 O emissions, and exacerbated soil P deficiency. These two factors partially offset the perceived beneficial effects of N addition on SOC storage in tropical forest soils. These findings suggest a potential to incorporate microbial community and functions into Earth system models considering their effects on greenhouse gas emission, biogeochemical processes and biodiversity of tropical ecosystems. This article is protected by copyright. All rights reserved.National Natural Science Foundation of ChinaNational Key R&D Program of ChinaYouth Innovation Research Team Projec

Runoff- and erosion-driven transport of cattle slurry:linking molecular tracers to hydrological processes

The addition of cattle slurry to agricultural land is a widespread practise, but if not correctly managed it can pose a contamination risk to aquatic ecosystems. The transport of inorganic and organic components of cattle slurry to watercourses is a major concern, yet little is known about the physical transport mechanisms and associated fluxes and timings of contamination threats. Therefore, the aim of the study was to ascertain the importance of flow pathway partitioning in the transport (fluxes and timing) of dissolved and particulate slurry-derived compounds with implications for off-site contamination. A series of rainfall–runoff and erosion experiments were carried out using the TRACE (Test Rig for Advancing Connectivity Experiments) experimental hillslope facility. The experiments allowed the quantification of the impact of changing slope gradient and rainfall intensity on nutrient transport from cattle slurry applied to the hillslope, via surface, subsurface, and vertical percolated flow pathways, as well as particulate transport from erosion. The dissolved components were traced using a combination of ammonium (NH₄⁺) and fluorescence analysis, while the particulate fraction was traced using organic biomarkers, 5<i>β</i>-stanols. Results showed that rainfall events which produced flashy hydrological responses, resulting in large quantities of surface runoff, were likely to move sediment and also flush dissolved components of slurry-derived material from the slope, increasing the contamination risk. Rainfall events which produced slower hydrological responses were dominated by vertical percolated flows removing less sediment-associated material, but produced leachate which could contaminate deeper soil layers, and potentially groundwater, over a more prolonged period. Overall, this research provides new insights into the partitioning of slurry-derived material when applied to an unvegetated slope and the transport mechanisms by which contamination risks are created

Bacteria and fungi respond differently to multifactorial climate change in a temperate heathland, traced with ¹³C-Glycine and FACE CO₂

It is vital to understand responses of soil microorganisms to predicted climate changes, as these directly control soil carbon (C) dynamics. The rate of turnover of soil organic carbon is mediated by soil microorganisms whose activity may be affected by climate change. After one year of multifactorial climate change treatments, at an undisturbed temperate heathland, soil microbial community dynamics were investigated by injection of a very small concentration (5.12 µg C g(-1) soil) of (13)C-labeled glycine ((13)C2, 99 atom %) to soils in situ. Plots were treated with elevated temperature (+1°C, T), summer drought (D) and elevated atmospheric carbon dioxide (510 ppm [CO2]), as well as combined treatments (TD, TCO2, DCO2 and TDCO2). The (13)C enrichment of respired CO2 and of phospholipid fatty acids (PLFAs) was determined after 24 h. (13)C-glycine incorporation into the biomarker PLFAs for specific microbial groups (Gram positive bacteria, Gram negative bacteria, actinobacteria and fungi) was quantified using gas chromatography-combustion-stable isotope ratio mass spectrometry (GC-C-IRMS). Gram positive bacteria opportunistically utilized the freshly added glycine substrate, i.e. incorporated (13)C in all treatments, whereas fungi had minor or no glycine derived (13)C-enrichment, hence slowly reacting to a new substrate. The effects of elevated CO2 did suggest increased direct incorporation of glycine in microbial biomass, in particular in G(+) bacteria, in an ecosystem subjected to elevated CO2. Warming decreased the concentration of PLFAs in general. The FACE CO2 was (13)C-depleted (δ(13)C = 12.2‰) compared to ambient (δ(13)C = ∼-8‰), and this enabled observation of the integrated longer term responses of soil microorganisms to the FACE over one year. All together, the bacterial (and not fungal) utilization of glycine indicates substrate preference and resource partitioning in the microbial community, and therefore suggests a diversified response pattern to future changes in substrate availability and climatic factors

Modelling the impact of targeted anthelmintic treatment of cattle on dung fauna

The insecticidal properties of many anthelmintics pose a risk to dung fauna through the effects of drug residues in dung on the activity, oviposition and development of dung-dwelling invertebrates. Reductions in dung fauna numbers can inhibit dung degradation, which may impact biodiversity and nutrient cycling on farms. A simulation model was created to predict the impact of antiparasitic drugs on cattle dung fauna, and calibrated using published data on the dung-breeding fly Scathophaga stercoraria. This model was then tested under different effective dung drug concentrations (EC) and proportions of treated cattle (PT) to determine the impact under different application regimens. EC accounted for 12.9% of the observed variation in S. stercoraria population size, whilst PT accounted for 54.9%. The model outputs indicate that the tendency within veterinary medicine for targeted selective treatments (TST), in order to attenuate selection for drug resistance in parasite populations, will decrease the negative impacts of treatments on dung fauna populations by providing population refugia. This provides novel evidence for the benefits of TST regimens on local food webs, relative to whole-herd treatments. The model outputs were used to create a risk graph for stakeholders to use to estimate risk of anthelminthic toxicity to dung fauna