Sampling Protocol Research Articles

Optimizing Tongue Fluid Sampling and Testing Protocols for Enhanced PRRSV Isolation from Perinatal Swine Mortalities

Porcine reproductive and respiratory syndrome virus (PRRSV) remains a major concern for swine health. Isolating PRRSV is essential for identifying infectious viruses and for vaccine formulation. This study evaluated the potential of using tongue fluid (TF) from perinatal piglet mortalities for PRRSV isolation. Four collection protocols were tested: extracting TF from fresh tissues using phosphate-buffered saline (PBS group), extracting TF from fresh tissues using virus transportation medium (VTM group), extracting TF from freeze-thawed tissue (freeze-thaw group), and using tissue homogenates (homogenate group). Two cell lines (ZMAC and MARC-145) and primary alveolar macrophages (PAM) were evaluated for their effect on successful PRRSV isolation. An eligible PRRSV-positive unstable breeding herd in Midwestern USA was chosen for the study. Tongues were collected in 20 batches (~30 mortalities per batch). Within each batch, each tongue tissue was cut into four quarters, with each quarter randomly assigned to one of the four collection protocols and RT-qPCR tested. Virus isolation (VI) was attempted on 10 batches. The mean RT-qPCR cycle threshold (Ct) values for the PBS, VTM, freeze-thaw, and homogenate groups were 21.9, 21.8, 22.6, and 24.8, respectively. The VI success rate was 22.6%, 12.1%, 2.8%, and 2.8% in the PBS, VTM, freeze-thaw, and homogenate groups, respectively. The probability of successful VI was 3.1% and 21.0% in the MARC-145 and ZMAC cell lines, respectively, and 4.8% in the PAM cells. TF from perinatal mortalities is an option for PRRS VI, aiding in PRRSV monitoring and control programs.

Mind the leaf anatomy while taking ground truth with portable chlorophyll meters

A wide range of portable chlorophyll meters are increasingly being used to measure leaf chlorophyll content as an indicator of plant performance, providing reference data for remote sensing studies. We tested the effect of leaf anatomy on the relationship between optical assessments of chlorophyll (Chl) against biochemically determined Chl content as a reference. Optical Chl assessments included measurements taken by four chlorophyll meters: three transmittance-based (SPAD-502, Dualex-4 Scientific, and MultispeQ 2.0), one fluorescence-based (CCM-300), and vegetation indices calculated from the 400–2500 nm leaf reflectance acquired using an ASD FieldSpec and a contact plant probe. Three leaf types with different anatomy were included: dorsiventral laminar leaves, grass leaves, and needles. On laminar leaves, all instruments performed well for chlorophyll content estimation (R2 > 0.80, nRMSE < 15%), regardless of the variation in their specific internal structure (mesomorphic, scleromorphic, or scleromorphic with hypodermis), similarly to the performance of four reflectance indices (R2 > 0.90, nRMSE < 16%). For grasses, the model to predict chlorophyll content across multiple species had low performance with CCM-300 (R2 = 0.45, nRMSE = 11%) and failed for SPAD. For Norway spruce needles, the relation of CCM-300 values to chlorophyll content was also weak (R2 = 0.45, nRMSE = 11%). To improve the accuracy of data used for remote sensing algorithm development, we recommend calibration of chlorophyll meter measurements with biochemical assessments, especially for species with anatomy other than laminar dicot leaves. The take-home message is that portable chlorophyll meters perform well for laminar leaves and grasses with wider leaves, however, their accuracy is limited for conifer needles and narrow grass leaves. Species-specific calibrations are necessary to account for anatomical variations, and adjustments in sampling protocols may be required to improve measurement reliability.

Towards estimating the proportion of dead and missing vines at the field level

This work aimed to improve practices for estimating dead and missing vines, particularly when these estimations are made via sampling. Vine mortality is a well-known phenomenon that many studies have attempted to better explain, but only a few have focused on estimating the number of dead and missing vines at the field-level, which remains a challenging task for grapegrowers. The present article aimed to determine to what extend an increased an increased sampling effort improves estimation accuracy and thus help practitioners define a sample size adapted to vineyard properties and the accuracy expected by the grower. The first part of the study investigated whether vineyard properties (year of planting and variety) and available ancillary data (soil resistivity and fraction of vegetation cover [Fcover]) can provide a priori information on the proportion of dead and missing vines and guide the sampling strategy. The analysis was based on an exhaustive dataset created by individually mapping 14,199 dead and missing vines across 29 fields in a 20 ha vineyard. In this vineyard, regression models showed an increase in dead and missing vines of around 2.2 % per year from the tenth year onwards. Plantation year, variety and vigour (assessed by Fcover) were identified as providing valuable prior information on the proportion of dead and missing vines within the fields. The second part of the study focused on characterising the estimation error values that can result from these estimations. It focuses on sampling estimation, highlighting to what extent field properties (such as the number of dead and missing vines and their spatial autocorrelation) affect the accuracy of estimates. The results showed that the same sampling protocol can result in different accuracies from one field to another. Thus, they underline the importance of leveraging prior information, such as available field data, to tailor sampling efforts accordingly. Based on these results, this article introduces new guidelines to facilitate the estimation of the proportion of dead and missing vines in vineyards.

Influence of mesh selectivity on risk assessment of marine microplastics.

In this study, environmental microplastic samples (>30μm) were collected from surface seawater and the water column, characterized, and used to assess ecological risks. The influence of mesh selectivity on ecological risks was also evaluated through subsampling. Results show that surface microplastic concentrations (>30μm) range from 92 to 3306 pieces/m3 along Japan's southwest coast, with significant increases at Stas. 2 and 1. Subsurface vertical concentration near Okinawa ranges from 991 to 1992 pieces/m3, with denser, more toxic polymers more frequently observed in deeper waters, suggesting that polymer types may be sorted by marine structure. Risk assessments revealed very high risks near main islands and populated regions, while remote regions had lower risks. Further analysis revealed that ecological risk estimates are significantly influenced by mesh selectivity, with variations in particle size distribution and polymer type composition resulting in changes of up to 100-fold at the same location when different mesh sizes were used, suggesting that current framework is not ideal for risk assessment of microplastics. This study is the first to demonstrate that samplers with different mesh sizes can lead to substantial differences in risk assessments, even at the same location. These findings underscore the critical impact of mesh selectivity on ecological risk estimates and highlight the need for standardized sampling protocols in microplastic research.

Optimization of Wetland Environmental DNA Metabarcoding Protocols for Great Lakes Region Herpetofauna

ABSTRACTMany species of reptiles and amphibians (herpetofauna) rely on wetlands that are being degraded and lost at a high rate. Characterization of herpetofauna diversity in different wetland types may help guide conservation strategies. However, traditional survey methods often involve sampling within small temporal windows, and the gear deployed may be taxonomically biased, thus, they may fail to accurately characterize species presence/absence and diversity. In contrast, environmental (e)DNA metabarcoding has been shown to effectively survey entire aquatic communities and can provide a useful complement to traditional surveys. The objective of this study was to design and optimize eDNA sampling and laboratory protocols for wetland herpetofauna. Protocols evaluated included different water sampling approaches (point versus transect sampling), seasonality of sampling, and choice of metabarcoding marker (mitochondrial 12S versus 16S rDNA). Samples collected from 10 sites across southern Michigan detected 17 amphibian and five reptile species, including four species of conservation concern (Ambystoma texanum, Clemmys guttata, Rana palustris, and Sternotherus odoratus). We observed no difference in the number of species detected between point and transect samples (p = 0.70), but point sampling required less time (p = 0.03) and allowed significantly larger volumes of water to be filtered (p = 1.13e‐5). No difference in species richness was observed between the 12S and 16S mitochondrial DNA markers (p = 0.96). However, a greater number of taxa were identifiable at the species level when using the 16S locus. There was also a significant difference in the number of species detected between early and late summer sampling periods (more species detected in the earlier period; p = 6.31e‐6), and some species were only found in the early or late sampling period. Sampling during multiple periods to fully characterize species composition, the use of point sampling, and the 16S mtDNA marker for herpetofauna eDNA metabarcoding studies may increase efficiency and reliability of results.

Emission Reduction Characteristics of Heavy-Fuel Aircraft Piston Engine Fueled with 100% HEFA Sustainable Aviation Fuel.

With the projected expansion of the general aviation sector and recent breakthroughs in sustainable aviation fuels (SAF), accurately measuring emissions from novel aircraft engines powered by SAF is paramount for evaluating the role of aviation industry in emission reduction trends and environmental consequences. Current SAF research primarily centers on low blend ratios, neglecting data on 100% SAF. This study bridges this gap by experimentally determining emissions indices for gaseous pollutants (CO, CO2, HC, NOx), total particulate matter (PM) counts and sizes, and non-volatile particulate matter (nvPM) number and mass concentrations from a heavy-fuel aircraft piston engines (HF-APE) using hydroprocessed esters and fatty acids-derived SAF (HEFA-SAF), adhering to airworthiness-standard sampling and measurement protocols. Additionally, nvPM morphology and structure are analyzed to auxiliarily assess the emission reduction. The results demonstrate that HEFA-SAF stands out for its marked reduction in both CO and HC gaseous pollutant compared to RP-3 aviation kerosene (RP3), as well as effectively reduces PM emissions compared to Diesel and RP3 across all load conditions. Notably, HEFA-SAF significantly curbs the generation of both nucleation-mode and accumulation-mode PM. Specifically, the use of HEFA-SAF leads to a 43% and 24% decrease in average nvPM number concentration, and a 65% and 53% reduction in average nvPM mass concentration respectively, compared to Diesel and RP3. At 50% load, nvPM produced by HEFA-SAF exhibits distinct nanostructural properties, characterized by fewer exposed pores and active sites within agglomerated particles. Rigorous emission testing has conclusively validated the substantial benefits of 100% HEFA-SAF in reducing emissions, offering a compelling rationale for the development of airworthiness regulations and environmental oversight frameworks designed to foster sustainable aviation practices.

Practical Two-party Computational Differential Privacy with Active Security

In this work we revisit the problem of using general-purpose MPC schemes to emulate the trusted dataholder in differential privacy (DP), to achieve the same accuracy but without the need to trust one single dataholder. In particular, we consider the two-party model where two computational parties (or dataholders), each with their own dataset, wish to compute a canonical DP mechanism on their combined data and to do so with active security. We start by remarking that available definitions of computational DP (CDP) for protocols are somewhat ill-suited for such a use-case, due to them either poorly capturing some strong security guarantees commonly given by general-purpose MPC protocols, or having too strict requirements in the sense that they need significant adjustment in order to be satisfiable by using common DP and MPC techniques. With this in mind, we propose a new version of simulation-based CDP, called SIM*-CDP, and prove it to be stronger than the IND-CDP and SIM-CDP and incomparable to SIM+-CDP. We demonstrate the usability of the SIM*-CDP definition by showing how to satisfy it by the use of an available distributed protocol for sampling truncated geometric noise. Further, we use the protocol to compute two-party inner-products with CDP and active security, and with accuracy equal to that of the central model, being the first to do so. Finally, we provide an open-sourced implementation and benchmark its practical performance. Our implementation generates a truncated geometric sample in between about 0.035 and 3.5 seconds (amortized), depending on network and parameter settings, comparing favourably to existing implementations.

Guaranteed Output in $$O(\sqrt{n})$$ Rounds for Round-Robin Sampling Protocols

Guaranteed Output in $$O(\sqrt{n})$$ Rounds for Round-Robin Sampling Protocols

Lightweight Two-Party Secure Sampling Protocol for Differential Privacy

Secure sampling is a secure multiparty computation protocol that allows a receiver to sample random numbers from a specified non-uniform distribution. It is a fundamental tool for privacy-preserving analysis since adding controlled noise is the most basic and frequently used method to achieve differential privacy. The well-known approaches to constructing a two-party secure sampling protocol are transforming uniform random values into non-uniform ones by computations (e.g., logarithm or binary circuits) or table-lookup. However, they require a large computational or communication cost to achieve a strong differential privacy guarantee. This work addresses this problem with our novel lightweight two-party secure sampling protocol. Our protocol consists of random table-lookup from a small table with the 1-out of-n oblivious transfer and only additions. Furthermore, we provide algorithms for making a table to achieve differential privacy. Our method can reduce the communication cost for (1.0, 2^(-40))-differential privacy from 183GB (naive construction) to 7.4MB.

Measuring soil carbon stocks with greater simplicity, accuracy, and repeatability

AbstractIf soil samples are collected using the traditional linear depth methods, comparisons of soil constituents are most often confounded with differences in soil bulk density. Recent interest in quantifying soil C stocks will therefore require improved soil sampling protocols. The dry mass per unit area method eliminates soil bulk density as a measurement factor and therefore allows unbiased comparisons between sampling dates, soil conditions, soil types, sampling techniques, and treatments that affect soil bulk density. This note explains how this simple change in quantifying soil depth eliminates soil bulk density as a factor and improves the quantification of soil C stocks.

Effect of glyceryl trinitrate and clevidipine administration on CT angiogram findings in dogs undergoing prostatic artery embolization for prostatic carcinoma.

The primary aim of this study was to evaluate the effects of vasodilator administration on CT angiography (CTA) prostatic artery diameter and peak opacification in dogs with prostatic carcinoma prior to prostatic artery embolization (PAE). A prospective clinical trial was performed. Ten dogs with naturally occurring prostatic carcinoma and no evidence of cardiovascular disease were enrolled. Each dog underwent multiphase CTA of the prostate before and after IV vasodilator (glyceryl trinitrate [GTN] or clevidipine butyrate [clevidipine]) administration, and cardiovascular parameters were monitored. PAE was performed the following day. Prostatic arterial anatomy was characterized by CTA. Prostatic artery lumen diameter and peak opacification were measured on pre- and post-vasodilator CTA by a blinded radiologist. The percent change of these measurements was calculated and assessed for significance. Glyceryl trinitrate and clevidipine were administered in 5 dogs each with subsequent blood pressure reduction documented in all dogs. No significant difference was detected in prostatic artery diameter or peak opacification between pre- vs. post-vasodilator CTA. Good agreement in prostatic arterial branch number, origin, and course was documented between pre- and post-vasodilator CTA images. Study findings do not support the routine use of vasodilator administration during pre-PAE CTA in dogs, though larger sample sizes and protocol alterations may be needed to detect a clinically relevant utility.

Comparison of different eGFR formulas to measured glomerular filtration rate using iohexol in children and adolescents with mild chronic kidney disease.

Estimated glomerular filtration rate (eGFR) based on different formulas is commonly used as a bedside tool to assess kidney function in children and young adults. The purpose of this study was to perform a measurement of glomerular filtration rate (mGFR) in children with chronic kidney disease (CKD) with a standard 5-point protocol using iohexol clearance and compare it to a simplified protocol for mGFR determination and to some of the most commonly used eGFR formulas. A 5-point standard protocol using iohexol clearance was used for determination of mGFR in 50 children with mild stages of CKD. The result was compared to 2- and 3-point sampling protocol as well as with some standard children eGFR formulas. We calculated the prediction performance for eGFR formulas to distinguish CKD1 and CKD 2 stages, formulas' accuracy, and cutoff values. Data were prospectively collected. All eGFR formulas exhibited a statistically significant positive correlation with mGFR. The best correlation was found with CKID2012 eGFR formula and with cystatin C-based eGFR formulas. The correlation between standard and simplified protocols for mGFR determination was also strong, while creatinine clearance did not prove to be a reliable method for estimating GFR. The error distribution with simplified protocols was not dispersed. The prediction value was strong for CKID2012 and bedside Schwartz formula. Conclusion: Fewer sampling points can be safely used for measuring GFR in children. eGFR formulas that are not based solely on creatinine should be considered more often in GFR estimation. What is Known? • Iohexol clearance is an established method of measuring GFR in children and adolescents using different protocols. • Estimating GFR in children and adolescents is troublesome and is done using different formulas with anthropometric and biochemical markers in children and adolescents. What is New? • Iohexol measurement with two or three blood withdrawals can reliably distinguish between CKD1 and CKD2 patients. • eGFR formulas have moderate reliability to predict distinguish between CKD1 and CKD2 patients, of which CKID2012 and bedside Schwartz formula were the most accurate in our study.

Absorption photometry of patterned deposits on IMPROVE PTFE filters

ABSTRACT The IMPROVE program (Interagency Monitoring of PROtected Visual Environments) tracks long-term trends in the composition and optics of regional haze aerosols in the United States. The absorptance of red (633-nm) light is monitored by filter photometry of 24 h-integrated samples of fine particulate matter (PM 2.5). These are collected every third day at about 150 rural and often remote locations. Systematic reanalyses of archived samples have established the reproducibility of these optical absorption measurements across decades and instrument systems, with a consistent calibration that is traceable back to 2003. IMPROVE samples for nondestructive analyses by photometry, gravimetry, and X-ray fluorescence are all collected on ring-mounted membranes of expanded PTFE (polytetrafluoroethylene). Although attractively inert, low in blank mass, and optically thin, these media yield visibly nonuniform deposits that do not admit direct interpretation according to a naïve “Beer-Lambert” formulation of optical absorption. Most IMPROVE PTFE deposits exhibit a fine-scale “pixelation” shaped by the perforated screen that supports the membrane during sample collection. This paper extends the traditional Beer-Lambert interpretive model to accommodate the patterned deposits generated by IMPROVE and similarly aggressive sampling protocols on PTFE filters. The extended model is then used to assess the bias and epistemic uncertainty in the aerosol absorption coefficient that IMPROVE has historically reported. Implications Ambient fine aerosol particles are widely collected at high sample face velocities on PTFE (Teflon®) membrane filters backed by perforated support screens. The screens’ localized blockage of airflow can channel the resulting PM2.5 sample deposits into a pattern of discrete heavily loaded “pixels”, where the screen perforations allow flow through the membrane, separated by a lightly loaded background that reflects blockage by the screen. Such non-uniform deposits, collected throughout the United States on FRM filters to monitor NAAQS compliance and on IMPROVE filters to support the Regional Haze Rule, do not meet the requirements of the Beer-Lambert model for optical absorption measurements. This paper extends Beer-Lambert theory to accommodate patterned deposits, and assesses the bias and epistemic uncertainties introduced by historical (mis)reporting based on “Beer’s Law”. For samples of moderate (and lesser) absorptance, including the bulk of those collected at rural IMPROVE sites to track regional haze, usefully tight bounds are developed for this pixelation bias.

Metagenomic analysis reveals the community composition of the microbiome in different segments of the digestive tract in donkeys and cows: implications for microbiome research

IntroductionThe intestinal microbiota plays a crucial role in health and disease. This study aimed to assess the composition and functional diversity of the intestinal microbiota in donkeys and cows by examining samples collected from different segments of the digestive tract using two distinct techniques: direct swab sampling and faecal sampling.ResultsIn this study, we investigated and compared the effects of multiple factors on the composition and function of the intestinal microbial community. Approximately 300 GB of metagenomic sequencing data from 91 samples obtained from various segments of the digestive tract were used, including swabs and faecal samples from monogastric animals (donkeys) and polygastric animals (cows). We assembled 4,004,115 contigs for cows and 2,938,653 contigs for donkeys, with a total of 9,060,744 genes. Our analysis revealed that, compared with faecal samples, swab samples presented a greater abundance of Bacteroidetes, whereas faecal samples presented a greater abundance of Firmicutes. Additionally, we observed significant variations in microbial composition among different digestive tract segments in both animals. Our study identified key bacterial species and pathways via different methods and provided evidence that multiple factors can influence the microbial composition. These findings provide new insights for the accurate characterization of the composition and function of the gut microbiota in microbiome research.ConclusionsThe results obtained by both sampling methods in the present study revealed that the composition and function of the intestinal microbiota in donkeys and cows exhibit species-specific and region-specific differences. These findings highlight the importance of using standardized sampling protocols to ensure accurate and consistent characterization of the intestinal microbiota in various animal species. The implications and underlying mechanisms of these associations provide multiple perspectives for future microbiome research.

Density and distribution of the flat mite (Brevipalpus yothersi) (Acari: Tenuipalpidae) on four Hibiscus varieties: do leaves tell the full story?

The flat mite, Brevipalpus yothersi (Baker, 1949) is widely distributed in the southern United States. This mite is associated with a citrus leprosis virus ((CiLV-C2) Cilevirus colombiaense strain hibiscus) infecting ornamental hibiscus (Hibiscus rosa-sinensis) in Florida and Hawaii. Because hibiscus is a highly traded ornamental plant, CiLV-C2 has the potential to spread. In laboratory experiments, the abundance and distribution of B. yothersi were studied on four varieties of tropical hibiscus. Plants, grown from cuttings, were infested with female mites, and held in environmental chambers (25 °C, 75% RH). After 3 months, the plants were divided into strata representing the top, middle and bottom of the plant. All mites (including eggs) found on the leaves and woody parts (main stems and side branches) were counted, and the surface area of each part calculated. The number and surface area of leaves and woody parts varied between hibiscus varieties; however, the differences between varieties with respect to total number of mites/plant and mites/cm2 were not statistically significant. There were twice as many mites on the woody parts than on the leaves. Most mites were found in the bottom stratum of the plants, and they showed an aggregated spatial distribution. The implications of mite distributions for assessing population sizes of B. yothersi were analyzed with the purpose of optimizing sampling without damaging the plant. The efficient sampling protocol developed is an important tool for managing the vector and thereby the disease.

Rapid Determination of Ti in Quartz Using a Portable/Handheld Laser-Induced Breakdown Spectroscopy (LIBS) Instrumentation: A Case Study on Quartz Veinlets in Hornfels from Italy

Recent advances in the use of portable/handheld laser-induced breakdown spectroscopy (LIBS) instrumentation have allowed its use directly in the field. In this study, a portable/handheld LIBS demo kit was tested to detect the titanium (Ti) content in some quartz veinlets hosted by hornfels collected from the contact aureole of a Pliocene granite from Italy. Results of the present study demonstrate the promising potential of LIBS in the rapid detection of low and very variable Ti contents in quartz, which can be used as a preliminary test for the estimation of the temperature of quartz crystallization in the laboratory. However, to date, the limited availability of matrix-matched calibration samples, the refinement of sampling protocols, as well as the development of suitable algorithms for data processing and spectral analysis still require further investigation.

A systematic review to assess current surface water and sediment microplastic sampling practices in seagrass and mangrove ecosystems.

Global plastic production is estimated to be 400 million tonnes per annum, with ~ 5.25 trillion fragments floating in our oceans. Microplastics (< 5mm) have the potential to disproportionately accumulate and become trapped in mangroves and seagrass meadows, creating plastic 'sinks'. This is concerning as these ecosystems are of great ecological and economic importance, with microplastics causing harm to inhabiting flora and fauna. However, accurately measuring microplastic abundance, comparing findings, and determining potential impacts are difficult due to a lack of standardised sampling protocols. Therefore, a systematic literature review was completed to review currently adopted microplastic sampling methods in surface water and sediment in seagrass and mangrove ecosystems. These were compared with recommendations from existing governmental and institutional groups as a first step to standardising methods for future sampling procedures in seagrasses and mangroves.

Surveillance of Drug Residue Profiles in Gallus gallus domesticus (Silkie Chickens) in Taiwan.

Veterinary drugs are extensively utilized in poultry farming for purposes such as disease prevention, disease treatment, and feed efficiency enhancement. However, the application of these drugs can lead to unacceptable residues in edible products. This study aimed to investigate the residue profiles of veterinary drugs in silkie chickens. A total of 130 chicken samples were collected from two major retail markets in Taiwan between 2022 and 2024. The analysis of drug residues was conducted using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The overall detection rate of drug residues was 57.7%, and most of these residues were found to be below the maximum residue limits. Among the detected drugs, trimethoprim was the most prevalent, followed by nicarbazin, robenidine, decoquinate, diclazuril, and sulfamonomethoxine. Notably, there was a 31.4% chance that different samples from the same flock would yield varying results. Furthermore, a positive correlation was observed between drug residues and sample weight. In conclusion, this study provides valuable epidemiological data on drug residue profiles in silkie chickens in Taiwan. In the future, it is highly recommended that veterinary drug residues be continuously monitored, and food product sampling protocols be adjusted annually to ensure ongoing compliance with safety standards and protect consumer health.

Evaluation and randomised controlled trial of home urinalysis testing in patients with SLE at elevated risk for developing lupus nephritis: a study protocol

IntroductionLupus nephritis (LN) is a frequent complication of SLE, occurring in up to 60% of adult patients and ultimately progressing from acute inflammation to chronicity with fibrosis and end-stage kidney...

Forage, freedom of movement, and social interactions remain essential fundamentals for the welfare of high-level sport horses.

Societal concerns for animal welfare extend to all domestic species, including high-level sport horses. The welfare of these horses, notably highlighted during the recent Olympics, has garnered significant public interest, prompting inquiries into their living conditions. Animal welfare studies have emphasised three key needs crucial to equine welfare: unlimited access to forage, freedom of movement, and social interactions with peers, commonly referred to as the "3Fs"-access to Forage, Freedom of movement, and interactions with Friend conspecifics. However, the feasibility and benefits of satisfying these needs specifically for sport horses remain unexplored. Indeed, they may face unique challenges such as high physical workload, extensive travel, limited time in their home stables, weight management, and high economic value necessitating careful handling. Consequently, restrictions on feeding, freedom of movement, and social contact are often deemed necessary. This field study aims to assess the actual level of implementation of welfare in high-level sport horses by evaluating body condition, injury risk, and behavioural welfare indicators in their home stable. To achieve this objective, the welfare of 56 high-level sport horses competing internationally was assessed using behavioural indicators of welfare through scan sampling (abnormal behaviours, i.e., stereotypies, aggression towards humans, withdrawn behaviour, and alert behaviours; positions of the ears in a backward position while foraging, watching behaviours, and through other Animal Welfare Indicators (AWIN) protocol measures). This study shows that there exists a large variability among horses regarding their access to the 3Fs, with some of them having a lot of restrictions and others not, meaning it is possible to respect them while competing at a high level. Second, we observed that the fewer restrictions the horses experience regarding the 3Fs while in their home stables, the better their welfare, as demonstrated by the indicators we assessed. These results undeniably support the fact that unrestricted access to forage, the ability to move freely outdoors, and the opportunity to interact socially with conspecifics are fundamental needs of horses that could be provided to horses, also to high-performance ones. It is therefore essential that solutions are put in place to ensure that these conditions are met.