David Dorchies
email: david.dorchies@inrae.fr

Mathias Chouet

Ludovic Cassan

Sylvain Richard

Dominique Courret

"Cassiopée" Software: a Tool to Assist in the Hydraulic Dimensioning of Upstream and Downstream Fish Passage Devices

Keywords: Software, Hydraulics, Fishway, Ecohydraulics

Engineers always need convenient calculation tools on the field or at the office for evaluating hydraulic characteristics and designing solutions while researchers develop scientific software in most cases nonreusable, invisible, and in the worst case, faulty and unreliable. Funded by the French Biodiversity Office, "Cassiopée" software has first been developed for the design and the verification of upstream and downstream fish passage facilities aggregating multiple tools required for dimensioning: pool-type fishways, pre-barrages, baffle fishways, nature-like fishways, and fish-friendly intakes. "Cassiopée" also includes numerous tools for open flow and pipe flow hydraulics for agriculture and environment. Based on calculation modules, which can be independent or linked in order to carry out complex operations, "Cassiopée" allows an iterative design approach ranging from the definition of the geometric characteristics of the devices to hydraulic simulations of their operating conditions. In a simple and user-friendly interface, it presents the calculation results as clear tables and graphs. Contextual documentation provides detailed information on the different tools and hydraulic formulas used for the calculations. Available in French and English, "Cassiopée" is an open source and free software accessible online (https://cassiopee.g-eau.fr) or as an offline application for Windows, Linux, macOS and Android. An R package is currently under development for advanced users who need to perform intensive calculations without a graphical user interface. Designed as a practical tool resulting from the transfer of research products, it is intended to be widely used by the hydraulic engineering community as a working and educational tool.

INTRODUCTION

From a software for fish passage designs…

The laboratory Pôle R&D écohydraulique, OFB-IMFT-PPRIME at Toulouse, France, has a long experience in fish passage design. This starts in the late 70's with studies on Denil Baffle fishways [START_REF] Larinier | Etude du fonctionnement d'une passe à poissons à ralentisseurs plans[END_REF], chevron-type baffle facilities for both fishes and canoes-kayaks [START_REF] Larinier | Etude expérimentale : dispositif mixte passe à poissons glissière à canoë-kayak[END_REF], and other baffles fishways (Larinier 1992[START_REF] Larinier | Baffle Fishways[END_REF]. At the time, the French government commissioned the laboratory to define construction standards for fish passes. As a result, the laboratory published fish passage design guides to state services, engineering offices and construction companies [START_REF] Larinier | Guide pour la conception des dispositifs de franchissement des barrages pour les poissons migrateurs[END_REF][START_REF] Larinier | Passes à poissons : expertise et conception des ouvrages de franchissement, Mise au point[END_REF]. More recently, the laboratory published technical guides for dimensioning nature-like fishways [START_REF] Larinier | Guide technique pour la conception des passes à poissons "naturelles[END_REF] and fish-friendly intakes [START_REF] Courret | Guide pour la conception de prise d'eau ichtyocompatibles pour les petites centrales hydroélectriques[END_REF].

From the 1980s, the laboratory also disseminated its expertise through software [START_REF] Larinier | Passes à poissons : expertise et conception des ouvrages de franchissement, Mise au point[END_REF] and in 1993, it released the first version of "Cassiopée" [START_REF] Larinier | Cassiopée -Logiciel d'aide au calcul pour le concepteur de passes à poissons -Notice d'utilisation[END_REF]. This latter allows the determination of flow and water level for dimensioning and verifying correct operation for:

x pool-type fishways (with plunging or streaming flow notches, submerged orifices, single or double vertical slots); x baffle fishways (with Denil type, Fatou type, super-active type or chevron type baffles);

x pre-barrages (with rectangular weir, triangular weir or semi-triangular weir).

Proceedings of the 39th IAHR World Congress 19-24 June 2022, Granada, Spain "Cassiopée" is since widely used in France and is the reference for dimensioning and verifying fishways design. Despite the release of a third version for Windows in 2012, the software is affected by several shortcomings:

x equations and algorithms used in the software are not well documented;

x types and combinations of hydraulic structures of pool-type fishways doesn't cover all current field situations; x nature-like fishways and fish-friendly intake devices are not implemented. The lack of documentation is an important point to raise. Indeed, as the software is used by the state services to check the conformity of fish passes, the results of the calculations must therefore be documented and reproducible so that they cannot be contested.

To cope with these issues, the French Biodiversity Agency (OFB) has worked in partnership with the UMR G-EAU at INRAE since 2016 to develop a new version of "Cassiopée". This was an opportunity to work on new interfaces based on the last standards of user experience adapted to modern communication devices.

To a general tool for hydraulic engineering calculations

The team "Hydraulic management, optimization and water transfer supervision" at G-EAU, Montpellier is focused on all aspects of 1D surface hydraulics modeling. The team is specialized in irrigation canal modelling and automatic regulation (Malaterre et al., 1998) and has developed the SIC² software for 30 years which is widely used by engineering offices for modeling irrigation canals and their controls [START_REF] Baume | SIC: a 1D hydrodynamic model for river and irrigation canal modeling and regulation[END_REF]. Stage discharge equations of hydraulic structures is also one of their concern [START_REF] Belaud | Calculation of Contraction Coefficient under Sluice Gates and Application to Discharge Measurement[END_REF][START_REF] Belaud | Contraction and Correction Coefficients for Energy-Momentum Balance under Sluice Gates[END_REF]. The require of the French Biodiversity Agency was an opportunity to spread the knowledge of the team with tools useful for both operational or student hydraulic engineers.

Besides the helper tools for designing fish passages facilities, we decided to propose some tools linked to surface hydraulics inspired by Canal9 [START_REF] Albert | Un outil conversationnel pour les calculs hydrauliques courants en canaux et rivières: le logiciel Canal 9[END_REF].

OVERALL CHARACTERISTICS OF THE NEW VERSION OF "CASSIOPÉE"

An application to use anywhere on any devices

We've made the choice of developing a single page web application with a responsive design adapted to all screens from smartphones to large computer screen. This solution allows to use directly the application online via the "Cassiopée" web site (https://cassiopee.g-eau.fr) with any recent web browser [START_REF] Dorchies | Cassiopée: tools for designing fish crossing devices for upstream and downstream migrations, and hydraulic calculation tools for environmental and agricultural engineering[END_REF]. The same source code is also compiled and deployed as a stand-alone application for Windows, Linux, MacOS, and Android operating systems for those who need to run the application without Internet connection. Figure 1 shows the look of the Android stand-alone application on a small screen.

An application organized into nested and linkable calculation modules

The application is organized into calculation modules. Each module consists in the resolution of an equation or a set of equations used to solve a dedicated problem. Every parameter of the equations can be either fixed to a single value or a series of values or set to be calculated (analytically or by numerical resolution). The calculation results show the set parameters, the calculated parameter and possibly additional results in tables and charts that can be exported in Excel or image format. This allow the user to answer to every situation considering known and needed parameters to be calculated.

The modules are based on a framework providing a genericity that both facilitates the development of new modules and offers a homogeneous user experience between the different modules. A working session of the application, which can be load or saved on the user terminal in json format, can contain as many calculations modules as needed. Some modules are nesting other modules such as the "Fish ladder" module that is made up of a series of "Fish ladder: Cross walls" themselves made up of one or several hydraulics structure equation modules which are also used in other modules (Pre-dams, Free flow weir stage-discharge laws…).

Calculation results or input parameters of one module can feed other module input parameters thanks to a link mechanism through the session. The application also provides a multi-module solver, which allows calculating through several linked modules where there is no direct computable solution. Figure 2 shows the diagram of several linked modules where one try to calculate the discharge passing by one submerged rectangular gates, a portion of a rectangular canal and a free flow rectangular weir with only knowing the upstream water level.

An open-source project with a complete theoretical documentation

To guaranty its stability and robustness, the application is developed following high standards in term of unit testing, regression tests, continuous integration and continuous deployment. As an example, at each modification in the source code, more than 1900 tests are executed.

Proceedings of the 39th IAHR World Congress 19-24 June 2022, Granada, Spain

One pitfall of the previous versions of "Cassiopée" was the lack of documentation and references. In order, to provide a total transparent tool, which anyone can check and understand, all the source code is released under the GNU Affero General Public license and is available on a public repository1 .

For the same reason, we produced a complete documentation of the calculation modules available in English and French with figures, equations and bibliographic references. All modules and all documented parameters and results are provided with a link to a contextual documentation, which deeply explain the hydraulics concepts and formulas used (Figure 3).

A COMPLETE TOOL FOR DESIGNING AND VERIFYING FISH PASSAGES

The installation of fish passage devices at weirs and dams is a measure to reduce their impact on the free movement of migratory fish. Their design must comply with a certain number of criteria in order to guarantee flow conditions in these devices that are favorable to their attractiveness and their passability by the target species identified. This new version of "Cassiopée" brings tools to help in design and verification of almost all kind of fishways (Figure 4). The tools allow the fishway designer or auditor to compute key hydraulic indicators for fish passage with all target hydraulic conditions by varying the flow crossing the device and upstream/downstream water elevations.

Pool-type fishways

Several modules are dedicated to the design of pool-type fishways also called "fish ladders". It starts from the calculation of the number of falls to allow the target fish species to swim upstream, the calculation of the dissipated power in each pool and finally the simulation of the entire fishways. Figure 5 shows a calculation result example of the effect of varying the downstream water elevation on the water surface within the pools.

Proceedings of the 39th IAHR World Congress

19-24 June 2022, Granada, Spain

Each wall of each pool can be equipped with any kind and any number of weirs and orifices with polyvalent stage-discharge equations taking into account transition between free or orifice flow and different levels of submergence.

Figure 5: charts of the water surface in a fish ladder for several downstream water elevation and a chart showing the average water depth in each pool for one downstream water elevation.

Baffle fishways

This part is divided into two modules: one used to design new fishways and the other to simulate hydraulic conditions for existing fishways, taking into account structural engineering specifications. It implements the equation developed by [START_REF] Larinier | Baffle Fishways[END_REF] for plane baffles (Denil), "Fatou" baffles, superactive baffles, chevrons baffles (mixed use for canoes-kayaks).

Nature-like fishpasses

The nature-like also called rock-ramp fishpass modules calculate hydraulic characteristics of a rock-ramp pass made up of uniformly distributed blocks (emergent or submerged and of various shapes). A module helps for the calculation of the block concentration, another one is adapted for calculation over a single not inclined apron fishpass, and a last one stands for inclined or multiple apron fish pass. These modules implement formulas and numerical resolution developed by Cassan et Laurens (2016[START_REF] Cassan | A Semi-Analytical Model for the Hydraulic Resistance Due to Macro-Roughnesses of Varying Shapes and Densities[END_REF], 2014).

Crossability verification

Migratory fish species have different abilities to cope with fishway hydraulic conditions, which depends on the type of fishway. On pool-type fishway, the following criteria are checked: jet type (surface or plunging), maximum fall between pools depending on the jet type, minimum slot width, minimum orifice surface, minimum head on weir, minimum water depth in the basins, and maximum dissipated power. On baffle fishways, the only criteria is the minimum water depth in the pass. On nature-like fish passes criteria are minimum water depth and maximum flow velocity.

Based on these criteria, the verification module allows to check the passability of a modeled fish pass for one or several fish species. "Cassiopée" implements the fish species criteria provided by the working group "Informations sur la Continuité Ecologique" [START_REF] Baudoin | The ICE protocol for ecological continuity -Assessing the passage of obstacles by fish. Concepts, design and application, Knowledge for action. The French national agency for water and aquatic environments[END_REF] as well as any user defined species criteria.

Fish-friendly intake devices

To cope with the issue of fish mortality caused by turbines at hydroelectric plants during their downstream migration, fish-friendly intakes, combining low bar-spacing rack and bypasses, can be installed. "Cassiopée" proposes a set of tools to dimension these devices. A first module is used to size the rack and to calculate head losses, in respect with equations developed by Raynal et al. for angled racks (2013a) and inclined racks (2013b). Then, different modules are used to size the weir which control the downstream flow ("Free flow weir stage-discharge laws"), to calculate hydraulic conditions in the downstream transfer canal ("Uniform flow calculation") and finally to check the jet trajectory and the fish reception conditions downstream ("Jet trajectory and impact").

Proceedings of the 39th IAHR World Congress

19-24 June 2022, Granada, Spain

TOOLS FOR EXPERIENCIED AND APPRENTICE HYDRAULIC ENGINEERS

Calculation in Open channels

"Cassiopée" implements several calculation tools related to open channel flow useful for rivers or canals. For all these modules, available section shapes are rectangular, trapezoidal, circular, or parabolic. The "Parametric section" module explores all possible hydraulic characteristics (head, flow velocity, head losses, critical and normal depths…). The "Uniform flow calculation" module allows to calculate any missing hydraulic parameter for a given uniform flow configuration. The "backwater curves" modules calculates supercritical, subcritical water surface as well as the water jump position if any. The "Upstream/downstream elevations of a reach" calculates, given an expected type of water surface (respectively subcritical or supercritical) any relevant hydraulic parameter (respectively upstream or downstream water elevation, flow, or roughness coefficient) of an homogeneous portion of river or canal through the calculation of the backwater curve.

These modules can be used as educational tools to explore and explain hydraulics phenomena. For example, Figure 6 shows that the location of a water jump is linked to the location where the conjugate depth crosses the water depth. Figure 7 shows outputs of the "Parametric section" module where calculation is done on a range of water depth demonstrating the minimum head is obtained at critical flow when the Froude is equal to 1.

Calculation on hydraulic structures

Several modules are related to hydraulic structures: "Parallel structures", "Free flow weir stage-discharge laws" and "Fish ladder: cross walls". All these modules are based on "Parallel structures" which calculates Proceedings of the 39th IAHR World Congress 19-24 June 2022, Granada, Spain relationship between upstream and downstream water level with the flow through one or several weirs or orifices layed out in parallel. The derived modules ("Free flow weir stage-discharge laws" and "Fish ladder: cross walls") calculate additional hydraulic parameters such as taking into account the water velocity in the stage-discharge equation or calculating criteria related to fish passability. Implemented stage discharge equations span several device geometries (orifices, rectangular weirs, triangular weirs, truncated triangular weirs and rectangular gates) with specific equations adapted to sharp crested or broad crested weirs as well as equations handling transition between free flow and submerged flow as well as free surface and orifice flow on rectangular gate. To help the user in the choice of a stage discharge equation, "Cassiopée" displays warning if some equation parameter is outside the validity domain of the equation. As shown in Figure 8, the interface facilitates the comparison of stage-discharge equations according to different parameters.

CONCLUSIONS AND ROADMAP

The release of the new version of "Cassiopée" took place in October 2020 with a communication and training sessions towards the French public administrations and engineering offices working on fish-passes. Since then, with more than 50.000 calculations triggered by more than 18.500 visitors during the year 2021, 76% of whom from France (statistics provided by online applications), "Cassiopée" is largely used in France. With more than 10% of the visitors accessing to "Cassiopée" with a smartphone, we can think that the application is actually used in a versatile way to make some quick calculations on the field, as well as at the office to carry out the design and verification of complex devices such as pool-type fishways (18.700 calculation reported in 2021) or pre-dams (5.400 calculations). Now, the majority of "Cassiopée" users are fish-passes designers but its wide range of hydraulic tools and its ease to use make "Cassiopée" an interesting tool to use in hydraulics education and civil engineering practice. Users can report malfunctions or wishes for the development of new features by e-mail or propose modifications to the code themselves to share with the community as the source code is open and released under AGPL3 license.

The development of a new module for velocity-area streamgauging is planned in 2022, implementing the ISO 748 norm (ISO, 2009) and uncertainty estimators [START_REF] Despax | Considering sampling strategy and cross-section complexity for estimating the uncertainty of discharge measurements using the velocity-area method[END_REF]). An R-package allowing to use "Cassiopée" calculation modules with the R language (R Core Team, 2021) for intensive calculations is also under development.

ACKNOWLEDGEMENTS

The development of "Cassiopée" has been funded by the French Biodiversity Agency within the framework of the OFB-Irstea conventions (Action n°100 of the 2016-2018 convention and Action n°21 of the 2019-2021 convention).

  Figure 1. Screenshots on an Android smartphone (From left to right: an input form for the calculation of an hydraulic structure, the table result of the calculation, a chart of the evolution of the flow function of the upstream water level on an hydraulic structure.

Figure 2 .

 2 Figure 2. Example of a calculation diagram of chained modules.

Figure 3 .

 3 Figure 3. Screenshot of the documentation concerning backwater curve calculation.

Figure 4 :

 4 Figure 4: Examples of fishways; from left to right: pool-type fishway, baffle fishway, nature-like fishpass (credit: Sylvain Richard, OFB)

Figure 6 :

 6 Figure 6: plot of a backwater curve with location of the water jump and the display of the conjugate water curve.

Figure 7 :

 7 Figure 7: charts of the specific head (left) and the Froude (right) function of the water depth in a rectangular section for a given flow.

Figure 8 :

 8 Figure 8: Plot of the flow crossing a rectangular weir depending on variation of downstream submergence for several stage-discharge equations: broad crested-weir (Cunge, 1980) (orange), sharp crested weir (Villemonte, 1948) (green), submerged slot (Larinier, 1992) (red), and deeply submerged sharp-crested weir (Rajaratnam, 1969) (purple).

https://gitlab.irstea.fr/cassiopee

©2022 IAHR. Used with permission / ISSN-L 2521-7119

©2022 IAHR. Used with permission / ISSN-L 2521-7119 Proceedings of the 39th IAHR World Congress 19-24 June 2022, Granada, Spain

The authors want to pay tribute to Michel Larinier, the creator of the first versions of "Cassiopée", who left us too early in 2020.


Anthony De Simone

Elias Aboudrar

Sophie Chazelle

Lisa Gerson

Benoit Chavillon

Eric Mayousse

Dane Sotta

Florence Rouillon

Sébastien Patoux

Evaluation of processing strategies for the manufacturing of Li-ion battery positive electrodes using non-solvent extrusion process

Evaluation of processing strategies for the manufacturing of Li-ion battery positive electrodes using non-solvent extrusion process

Lithium-ion batteries have known a considerable growth as energy storage devices in portable electronics applications, but also in electrified vehicles and stationary systems over the last few years. Cell manufacturers are looking for technical solutions to further reduce the costs of production lines. One of the critical steps is the production of positive and negative electrodes, i.e. the preparation of slurries and coating on current collectors. These complex stages involve the use of solvents that have to be removed during an energy-consuming drying phase. This is of particular importance for the production of positive electrodes where state-of-the-art industrial process is based on the use of carcinogenic N-methyl-2pyrrolidone (NMP) solvent, which implies the use of safety protocols and equipment for solvent recovery and recycling.

Alternatives to this conventional manufacturing route have been proposed such as extrusion, a wellknown process in the plastics industry. Extrusion allows to work with viscous matrices by combining the mixing (homogenisation, dispersion) and film forming (flat die extrusion, lamination) in a continuous way. Generally, the use of solvents is very limited or even eliminated, which makes it an innovative process compared to the standard one. Its industrialisation in the field of batteries therefore seems to be relevant because it combines a continuous process, a small footprint and limited costs.

Here we report the evaluation of two different strategies for the production of porous cathodes for Li-ion batteries without the need of NMP. In one hand, the use of small amount of water in the electrode composition is evaluated and its impact on battery lifetime is characterized. On the other hand, solid blowing agents are directly added in the formulation to create pores by thermally activated decomposition reactions. The impact of these new processes on the electrode morphology is thoroughly characterized with the help of scanning electronic microscope, helium pycnometer and mercury intrusion porosimeter. Electrochemical performances of promising samples are evaluated after assembly of coin and pouch cells. Finally, optimization routes are proposed toward energy-saving and dry processes for electrode manufacturing.

  A. De Simone, E. Aboudrar, S. Chazelle, L. Gerson, B. Chavillon, E. Mayousse, D. Sotta, F. Rouillon, S.

	Patoux
	CEA, Department for Electrical and Hydrogen Transportation (LITEN/DEHT/STB/L2PC),
	17 avenue des Martyrs, F-38054 Grenoble Cedex 9, France
	e-mail address: dane.sotta@cea.fr
	Session 2: Electrode production


Léa Bordes
email: lea.bordes@envt.fr

Denis Ticoulet

 Jean

François Sutra

Anne Lespine

Philippe Jacquiet

Lack of efficacy of topical administration of eprinomectin against gastrointestinal nematode in a French dairy sheep farm: A case of underexposure of worms

Resistance to eprinomectin was suspected in a dairy sheep farm in southwestern France. The efficacy of topical and injection formulations of eprinomectin against gastrointestinal nematodes (GINs) was compared using a faecal egg count reduction test. GIN species were identified by real-time PCR, and eprinomectin concentrations were measured in serum by High-Performance Liquid Chromatography 2 and 5 days after treatment. Efficacies were 99.6% and 86.1% for injection and topical formulations, respectively. Before treatment, the three species Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis were identified in both groups. After treatment, H. contortus and T. colubriformis were identified in the topical group only. Two days after treatment, eprinomectin concentrations were above 2 ng/ml in the injection group and under this value in the topical group, suggesting underexposure of GIN to eprinomectin in this latter group. High levels of exposure to eprinomectin are important to avoid loss of efficacy in the field.

BACKGROUND

The control of gastrointestinal nematode (GIN) infection in small ruminants essentially involves chemical control due to the low cost and treatment convenience for the farmers. However, risky practices, such as frequent and systematic use of the same anthelmintic family, may promote the emergence of resistance to GINs. For decades, benzimidazoles have been widely used, but the resistance of GINs to this family is now well established in many countries including France. [START_REF] Chartier | Prevalence of anthelmintic resistance in gastrointestinal nematodes of dairy goats under extensive management conditions in southwestern France[END_REF][START_REF] Geurden | Anthelmintic resistance and multidrug resistance in sheep gastro-intestinal nematodes in France, Greece and Italy[END_REF][START_REF] Jaeger | Status of benzimidazole resistance in intestinal nematode populations of livestock in Brazil: a systematic review[END_REF][START_REF] Papadopoulos | Anthelmintic resistance in sheep in Europe: a selected review[END_REF][START_REF] Torres-Acosta | Anthelmintic resistance in sheep farms: update of the situation in the American continent[END_REF] Consequently, small ruminant farmers have switched to the macrocyclic lactone (ML) family; but recently, resistance to ivermectin has been reported for the first time on French meat sheep farms. [START_REF] Cazajous | Multiple-resistance to ivermectin and benzimidazole of a Haemonchus contortus population in a sheep flock from mainland France, first report[END_REF][START_REF] Paraud | Crossresistance to moxidectin and ivermectin on a meat sheep farm in France[END_REF] In small ruminants, both formulations of eprinomectin have recently been registered in Europe for the control of GIN and lungworms. High levels of efficacy against GIN in small ruminants have been reported for topical [START_REF] Hamel | Eprinomectin pour-on (EPRINEX® Pour-on, Merial): efficacy against gastrointestinal and pulmonary nematodes and pharmacokinetics in sheep[END_REF][START_REF] Hamel | Pour-on administration of eprinomectin to lactating dairy goats: pharmacokinetics and anthelmintic efficacy[END_REF][START_REF] Chartier | Activity of eprinomectin in goats against experimental infections with Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis[END_REF] and injectable [START_REF] Termatzidou | Anthelmintic activity of injectable eprinomectin (eprecis® 20 mg/mL) in naturally infected dairy sheep[END_REF][START_REF] Lespine | Eprinomectin in goat: assessment of subcutaneous administration[END_REF][START_REF] Briqué-Pellet | Pharmacokinetics and anthelmintic efficacy of injectable eprinomectin in goats[END_REF] formulations of eprinomectin, while their dosing is quite different: the pour-on (PO) formulation is dosed at 1.0 mg/kg per kg bodyweight (BW), and the injectable (SC) formulation is dosed at 0.2 mg/kg BW.

One of the main dangers for the small ruminant dairy industry is the resistance of GIN to eprinomectin, of which a first French case was recently published on a dairy goat farm. [START_REF] Bordes | First report of multiple resistance to eprinomectin and benzimidazole in Haemonchus contortus on a dairy goat farm in France[END_REF] Not all treatment failures are due to GIN resistance but can also be due to low exposure of the animal to this drug due to subtherapeutic dosage or impaired absorption.

In this study, we investigated the reason for the lack of efficacy following topical application of eprinomectin in dairy sheep.

CASE PRESENTATION

This case involved a blond-faced Manech dairy sheep breed farm located in the Pyrénées-Atlantiques département in southwestern France. This flock, composed of 300 dairy ewes and 60 replacement ewes lambs, grazes 10 months per year. To control GIN infections, the farmer uses on average two treatments per year, one with eprinomectin during lactation and another one during the dry period with ivermectin. In March 2019, the practitioner noticed, during a visit requested by the farmer, signs of anaemia in about 10% of the lactating ewes determined by FAMACHA criteria [START_REF] Van Wyk | The FAMACHA system for managing haemonchosisin sheep and goats by clinically identifying individual animals for treatment[END_REF] and an average body condition scores around 2.5 [START_REF] Kenyon | Review of sheep body condition score in relation to production characteristics[END_REF] despite an anthelminthic treatment performed by the farmer in February 2019.

Following this observation, the practitioner proposed to evaluate the efficacy of eprinomectin by comparing PO and subcutaneous (SC) routes of administration.

INVESTIGATIONS

A faecal egg count reduction test (FECRT) was performed as described by Coles et al. [START_REF] Coles | World Association for the Advancement of Veterinary Parasitology (WAAVP) methods for the detection of anthelmintic resistance in nematodes of veterinary importance[END_REF] At the end of March 2019, ewes were randomly assigned to three groups of 12 animals: an untreated group (control group), an eprinomectin-treated group with the PO formulation (EPRINEX Multi, Boeringher Ingelheim, 1 mg/kg BW) and an eprinomectin-treated group with the SC formulation (EPRECIS, CEVA Santé Animale; 0.2 mg/kg BW). Treatments were carried out by the practitioner, who was careful to part the wool and deposit the product on the skin of the animal for the PO formulation. Ewes were dosed at the rate recommended by the manufacturer for 80 kg, which was heavier than the heaviest animal in the group: the average weight of blond-faced Manech ewes is around 60 kg. The identification number of the ewes was taken, and they were marked with coloured spray paint to ensure their quick identification in the flock for blood and faeces sampling. Faecal samples were collected individually to determine the GIN egg excretion. The number of eggs per gram (EPG) of faeces was determined by using the modified McMaster method, [START_REF] Raynaud | Etude de l' efficacité d'une technique de coproscopie quantitative pour le diagnostic de routine et le contrôle des infestations parasitaires des bovins, ovins, équins et porcins[END_REF] with a sensitivity of 15 EPG. Animals excreting less than 150 EPG were excluded from the study. On day 14, individual faecal samples collected again, and the percentage of reduction was calculated according to the formula: [START_REF] Coles | World Association for the Advancement of Veterinary Parasitology (WAAVP) methods for the detection of anthelmintic resistance in nematodes of veterinary importance[END_REF] Efficacy = 100 × (1arithmetic mean EPG of the treated group at day 14/arithmetic mean EPG of the control group at day 14)

Other calculation methods, taking into account the D0 of each group, estimate the same efficacies. Therefore, we have only used the guidelines formula.

According to the guidelines, [START_REF] Coles | World Association for the Advancement of Veterinary Parasitology (WAAVP) methods for the detection of anthelmintic resistance in nematodes of veterinary importance[END_REF] anthelminthic resistance is confirmed when the percentage of reduction is less than 95% and the lower 95% confidence interval is less than to 90%.

On day 0 (D0) and day 14 (D14), composite larval cultures were made for each group to identify GIN species. Each animal contributed more or less equally (4-5 g of faeces), but for some animals, the quantity of faeces was not sufficient, and such animals contributed poorly to the composite larval cultures (0-3 g of faeces). These animals were few in number (less than five in total in the study), which should not have had a major impact on the larval culture results.

Larvae were collected by filling the beaker with tap water and inverting it on a Petri dish at room temperature (± 25 • C) in a volume of 40-45 ml of tap water 19 before centrifugation (10 minutes at 3500 rpm) to concentrate the larvae to a final larval suspension volume of 5 ml. These suspensions were stored at 4 • C until identification. The identification of GIN species was performed using real-time PCR assays. [START_REF] Milhes | A real-time PCR approach to identify anthelmintic-resistant nematodes in sheep farms[END_REF] Briefly, 500 µl of homogenised larval suspension allowed the extraction and purification of genomic DNA with the

LEARNING POINTS/TAKE-HOME MESSAGES

• Pour-on administration of eprinomectin gives plasma concentrations below the minimum required plasma concentrations, which leads to underdosing and failure of treatment. • The eprinomectin Pour-on formulation is less effective than the injectable formulation, while using a five times higher dosage represents an increased environmental risk. • The lack of efficacy of anthelmintics is not always synonymous with gastrointestinal nematode (GIN) resistance. It may also originate from an insufficient exposure of worms to the drug. • In a sustainable approach to GIN control, it is advisable to use the formulation with the best bioavailability and the least ecotoxicity.

OWNER'S PERSPECTIVE

In the presented case, eprinomectin is still effective.

During the lactation period, this sheep breeder will be invited to perform eprinomectin treatments with an injectable formulation, and the dosage will be based on the weight of the heaviest animal in the treated group. Outside the lactation period, the farmer can use another class of drugs to treat his animals, such as closantel, authorised in France for dairy ewes at the beginning of the dry period to avoid exclusive use of avermectins in his flock.

DNeasy PowerSoil kit (QIAGEN). The primers and probes used and the PCR process are described in Milhes et al. [START_REF] Milhes | A real-time PCR approach to identify anthelmintic-resistant nematodes in sheep farms[END_REF] and can specifically detect and quantify Haemonchus contortus, Trichostrongylus colubriformis and Teladorsagia circumcincta larvae. Blood samples were collected from the two eprinomectintreated groups at day 2 (D2) and day 5 (D5) after treatment. Individual plasma eprinomectin concentrations were determined using the High-Performance Liquid Chromatography (HPLC) method, [START_REF] Sutra | Determination of eprinomectin in plasma by high-performance liquid chromatography with automated solid phase extraction and fluorescence detection[END_REF] with a limit of quantification of 0.07 ng/ml and interassay coefficients of variation below 5%.

OUTCOME AND FOLLOW-UP

The results of FECRT are reported in Table 1. Eprinomectin PO showed an efficacy of 86.1% (79.1-93.1), while the eprinomectin injection showed an efficacy of 99.6% (98.2-101).

The species composition of larval suspensions obtained after faecal cultures in the three groups before and after eprinomectin treatment is reported in injection eprinomectin due to the fact that only one animal still excreted GIN eggs at a very low excretion intensity (50 EPG). For the PO-treated group, the proportion of H. contortus decreased (36%) and those of T. colubriformis increased (63.7%).

The results of individual eprinomectin plasma concentrations at D2 and D5 posttreatment are reported in Figure 1. In the eprinomectin injection group, the mean concentrations were 7.44 ± 2.48 ng/ml at D2 and 1.91 ± 1.20 at D5. In the eprinomectin PO group, the mean concentrations were 1.12 ± 0.38 ng/ml and 1.26 ± 0.37 ng/ml at D2 and D5, respectively. Important individual variations were noticed in the two groups treated with eprinomectin. Despite animals in the eprinomectin PO group being treated with a dosage five times higher than animals in the eprinomectin injection group, this latter group showed the highest eprinomectin plasma concentrations at D2.

DISCUSSION

In this study, the efficacy of two formulations of eprinomectin (injection and topical) was investigated in a dairy sheep farm in southwestern France. The GIN species recovered were mainly H. contortus and, in smaller quantities, T. circumcincta and T. colubriformis. These differences in proportions are not surprising according to the ecology of H. contortus. Indeed, the region has a temperate climate with high annual rainfall (over 1500 mm per year), which is well suited to the development of this parasite. [START_REF] Zajac | Gastrointestinal nematodes of small ruminants: Life cycle, anthelmintics, and diagnosis[END_REF] The FECRT results clearly showed a discrepancy between the two formulations: A low efficacy was detected for the PO group, whereas injectable eprinomectin was fully efficient. This result is surprising considering that the concentration of eprinomectin is five times higher in the topical formulation than in the injectable formulation.

These results do not support the hypothesis of GIN resistance to eprinomectin on this farm but rather an underexposure of GIN in the case of topical formulation. If there had been GIN resistance, both formulations should have shown reduced efficacy. [START_REF] Bordes | First report of multiple resistance to eprinomectin and benzimidazole in Haemonchus contortus on a dairy goat farm in France[END_REF] Previous studies reported resistance to eprinomectin mainly in one GIN species, in particular, H. contortus. [START_REF] Ramos | Anthelmintic resistance in gastrointestinal nematodes of beef cattle in the state of Rio Grande do Sul, Brazil[END_REF][START_REF] Scheuerle | Anthelminthic resistance of Haemonchus contortus in small ruminants in Switzerland and South-ern Germany[END_REF][START_REF] Murri | Frequency of eprinomectin resistance in gastrointestinal nematodes of goats in canton Berne, Switzerland[END_REF] To validate the hypothesis of underexposure of GIN to eprinomectin, plasma concentrations at days 2 and 5 were compared between the two treated groups. The concentrations measured showed some differences from those of previous studies. [START_REF] Hamel | Pour-on administration of eprinomectin to lactating dairy goats: pharmacokinetics and anthelmintic efficacy[END_REF][START_REF] Briqué-Pellet | Pharmacokinetics and anthelmintic efficacy of injectable eprinomectin in goats[END_REF][START_REF] Bordes | First report of multiple resistance to eprinomectin and benzimidazole in Haemonchus contortus on a dairy goat farm in France[END_REF][START_REF] Rehbein | Pharmacokinetics and anthelmintic efficacy of topical eprinomectin in goats prevented from grooming[END_REF] Serum concentration levels were higher at days 2 and 5 in animals treated with injectable eprinomectin, compared to animals treated with the PO formulation; this difference has been shown previously in goats. [START_REF] Bordes | First report of multiple resistance to eprinomectin and benzimidazole in Haemonchus contortus on a dairy goat farm in France[END_REF] However, serum eprinomectin concentrations in the PO group in this study were lower than those obtained in the study of Hamel et al. [START_REF] Hamel | Eprinomectin pour-on (EPRINEX® Pour-on, Merial): efficacy against gastrointestinal and pulmonary nematodes and pharmacokinetics in sheep[END_REF] These differences can be explained by biological and physiological differences in the animal used for the test. The animals used in this test were ewes of dairy breed, of various ages, some of them heavily parasitised, at the peak of milk production. In Hamel et al.'s study, [START_REF] Hamel | Eprinomectin pour-on (EPRINEX® Pour-on, Merial): efficacy against gastrointestinal and pulmonary nematodes and pharmacokinetics in sheep[END_REF] the animals used were non-lactating ewes from Merino crosses, 4.5 years old, not pregnant and not parasitised. This has been shown by Rostang et al. [START_REF] Rostang | Review of the Eprinomectin effective doses required for dairy goats: where do we go from here?[END_REF] that these differences induce important differences in pharmacokinetics.

Previous studies have proposed a minimal active concentration of 2 ng/ml for MLs including eprinomectin. [START_REF] Hamel | Eprinomectin pour-on (EPRINEX® Pour-on, Merial): efficacy against gastrointestinal and pulmonary nematodes and pharmacokinetics in sheep[END_REF][START_REF] Guillot | Concentration of ivermectin in bovine serum and its effect on the fecundity of psoroptic mange mites[END_REF] In our study, only the injectable eprinomectin group reached these concentrations in all individuals. In contrast, in the PO eprinomectin group, no animal reached this concentration, which may explain the low efficacy in this group. Thus, the low efficacy observed and its impact on the three identified GIN species are likely due to a lack of drug exposure and not to GIN resistance to eprinomectin.

A high frequency of treatment with the same molecule class and underexposure of nematodes to the active molecule are risk factors for the development of resistance. [START_REF] Silvestre | Sheep and goat nematode resistance to anthelmintics: pro and cons among breeding management factors[END_REF][START_REF] Falzon | Comparison of calculation methods used for the determination of anthelmintic resistance in sheep in a temperate continental climate[END_REF] Added to other risk factors, such as the introduction of animals carrying resistant nematodes in the flock, [START_REF] Silvestre | Sheep and goat nematode resistance to anthelmintics: pro and cons among breeding management factors[END_REF] transhumance (use of summer grazing pasture common to several flocks) or the systematic and exclusive use of MLs, the long-term efficacy of eprinomectin is affected.

The ecotoxicity of eprinomectin for both aquatic and terrestrial fauna is well known, particularly for dung beetles, which are natural recyclers of faeces on pastures. [START_REF] Lumaret | Use of anthelmintics in herbivores and evaluation of risks for the non target fauna of pastures[END_REF][START_REF] Lumaret | A review on the toxicity and non-target effects of macrocyclic lactones in terrestrial and aquatic environments[END_REF] For a good trade-off between efficacy and a minimal risk for the environment, it is necessary to choose the formulation with the best bioavailability, the lowest concentration of the molecule administered to the animals and then the lowest contamination of pastures. As a result, the topical formulation seems inadequate for this issue. It appears that the use of a formulation five times more than the injectable formulation presents not only a lower absorption but also an important release of the product in the environment.

As the emergence of resistance and multiresistance of GINs to eprinomectin in small ruminants is an hot important in the region, [START_REF] Bordes | First report of multiple resistance to eprinomectin and benzimidazole in Haemonchus contortus on a dairy goat farm in France[END_REF] it is interesting to investigate cases of suspicion in the field to discriminate between resistance and improper use of the molecule. This investigation will allow the practitioner as well as the farmer to know the cause of the therapeutic failure they may encounter, but it will also support a decision to modify practices that may be at risk regarding the management of GINs during the lactation period.

A C K N O W L E D G E M E N T

This study was self-funded by the UMT Pilotage de la Santé des Ruminants without any funding from private companies.

C O N F L I C T S O F I N T E R E S T

The authors declare they have no conflicts of interest.

F U N D I N G I N F O R M AT I O N

The authors received no specific funding for this work.

E T H I C S S TAT E M E N T

Stool and blood collection and anthelminthic treatments are a part of routine veterinary procedures without any traumatic method. Such procedures are not qualified as animal experimentation involving vertebrates according to French laws, so no specific ethical clearance was required.

O R C I D

Léa Bordes https://orcid.org/0000-0002-2286-9925

R E F E R E N C E S

Table 2 .

 2 The predominant species in all groups (with over 90%) was H. contortus at D0. At D14, the species composition did not change in the control group. No larvae were obtained in the group treated with 20526121, 0, Downloaded from https://bvajournals.onlinelibrary.wiley.com/doi/10.1002/vrc2.435 by Cochrane France, Wiley Online Library on [27/10/2022]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Faecal egg count at day 0 and day 14 (after eprinomectin treatment) and results of the faecal egg count reduction test (FECRT)[START_REF] Coles | World Association for the Advancement of Veterinary Parasitology (WAAVP) methods for the detection of anthelmintic resistance in nematodes of veterinary importance[END_REF]

	Veterinary Record Case Reports

Abbreviation: RT-PCR, real-time PCR.

F I G U R E  Eprinomectin concentrations in plasma at days 2 and 5 post-treatment in ewes treated with (circles) eprinomectin injection (Eprecis ND; 0.2 mg/kg bodyweight [BW]) or (triangles) eprinomectin pour-on (Eprinex Multi ND; 1 mg/kg BW). Days 2 and 5 are individually expressed for each ewe. Dashed lines show the minimal active concentration for full efficacy for macrocyclic lactones,

[START_REF] Hamel | Eprinomectin pour-on (EPRINEX® Pour-on, Merial): efficacy against gastrointestinal and pulmonary nematodes and pharmacokinetics in sheep[END_REF][START_REF] Guillot | Concentration of ivermectin in bovine serum and its effect on the fecundity of psoroptic mange mites[END_REF]

estimated to be 2 ng/ml at day 2. The black bar represents the average concentrations in each treatment group and on each date

20526121, 0, Downloaded from https://bvajournals.onlinelibrary.wiley.com/doi/10.1002/vrc2.435 by Cochrane France, Wiley Online Library on [27/10/2022]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License