Abstract Background Gastrointestinal nematodes (GINs) have a major impact on sheep production, health, and welfare worldwide. Norway is no exception, but there are only a few studies on the prevalence of GINs in Norwegian sheep. The aim of this study was to investigate the current occurrence of the most important nematodes in sheep flocks in Norway. Faecal samples were collected from flocks in 2021/2022, mainly from three geographical regions in Norway, i.e., northern, eastern, and western. In each of 134 flocks included, individual samples from 10 lambs (autumn) were pooled. Third stage larvae (L3) were cultivated and harvested (Baermann method) from the pooled samples. The DNA was then extracted and further analysed using droplet digital PCR (ddPCR). This enables assessment of the proportions of the three most important nematode species/genera, i.e., H. contortus, T. circumcincta, and Trichostrongylus. The fractional abundance/relative proportion of each species/genus was assessed by performing duplex assays with universal strongyle and species/genus-specific primers and probe sets. In addition, the occurrence of Nematodirus eggs was assessed by standard faecal egg counts (i.e., McMaster method). Results Of the 134 flocks sampled, 24 were from the northern region, 31 from eastern, and 71 from western Norway. In addition, some flocks from central (n = 7), and southern (n = 1) Norway were included. Among the sampled flocks, T. circumcincta occurred most commonly (94%), followed by H. contortus (60%) and Trichostrongylus (55%), and Nematodirus (51%). In general, mixed infections were observed, with 38% and 18% of flocks infected with three or all four genera, respectively. Conclusions The results of this study indicate that GINs are widespread in Norway. Teladorsagia circumcincta seems to be present in most flocks based on this screening. Moreover, the results show that Nematodirus spp. infect lambs throughout the country, predominantly N. battus, and indicate that this nematode has become more abundant, which could lead to an increase in nematodirosis.

The aim of this study was to investigate the occurrence of benzimidazole-resistant Haemonchus contortus in Norwegian sheep flocks. Screening was based on detection of one of the resistance-conferring mutations in the beta tubulin isotype 1 gene (F200Y, TAC) in larvae (L3) cultivated from H. contortus eggs from naturally infected sheep. Faecal samples were collected in 2021/2022 from flocks in the northern (n = 34), central (n = 7), eastern (n = 40), southern (n = 1), and western (n = 87) areas of Norway. In total, samples were taken from 169 flocks (spring-ewes samples: 167, autumn-lambs samples: 134). Individual faecal samples were collected from 10 randomly selected ewes (spring) and 10 randomly selected lambs (autumn) in each flock. Faecal samples collected from each flock on each occasion were pooled (lamb and ewe samples pooled separately) and cultured for L3 development. After harvest of larvae (Baermann method), DNA was extracted and then analysed using droplet digital PCR with primer/probe sets targeting the BZ-associated F200Y (TAC) mutation. Haemonchus was found in 60% (80/134) of samples from lambs, and in 63% (106/167) from ewes. Among these, the F200Y mutation was detected in 73% (58/80) of larval samples from lambs and 69% (73/106) of larval samples from ewes, respectively. Although regional differences were evident, the mutation was detected in all areas indicating a widespread distribution and a strong potential for an increasing problem with treatmentresistant haemonchosis in Norwegian sheep flocks.

Les parasites (Helminthes, Protozoaires, Acariens, Insectes) restent responsables de pathologie majeures impactant l’élevage des ruminants. Pendant des décennies, la maitrise de ces divers groupes de parasites a reposé pour l’essentiel sur des molécules de synthèse développées par l’industrie pharmaceutique. Cependant, cette gestion quasi exclusive par des traitements chimiques se trouve désormais confrontée à plusieurs limites : d’une part, une demande sociétale croissante pour réduire les intrants chimiques en élevage dans le cadre d’une agriculture évoluant vers des critères agroécologiques ; d’autre part, le phénomène général de résistances aux antiparasitaires dans les différents groupes mentionnés. Dans ce contexte, le concept de gestion intégrée du parasitisme fondée sur une combinaison de solutions alternatives aux molécules de synthèse devient le nouveau paradigme de lutte applicable aux divers groupes de pathogènes. L’objectif de cette revue est de présenter quelques exemples de solutions complémentaires aux substances de synthèse en se fondant sur deux modèles principaux : les nématodes gastro intestinaux et les insectes chez des petits ruminants ou les bovins.

Clostridial infections in goats have been associated frequently with enteric diseases or gas gangrene but very rarely with the reproductive system. We describe here 12 cases of fatal postpartum gangrenous metritis in does associated with infection by several clostridial species. Clinically, these cases were characterized by rapid onset of hyperthermia followed by death after kidding. On postmortem examination, the uteri appeared to be necrotic and were hemorrhagic and edematous. Microscopically, the uteri had diffuse coagulative necrosis, edema, hemorrhage, and fibrinous thrombi with intralesional gram-positive rods. Clostridium perfringens was isolated from 7 of 9 uterine samples cultured, and C. perfringens, C. septicum, C. novyi, or C. chauvoei were demonstrated by immunohistochemistry (IHC) in the 5 cases examined. IHC for Paeniclostridium sordellii was negative in all 5 cases. PCR performed on 3 of the C. perfringens isolates was positive for alpha toxin and perfringolysin, identifying these isolates as type A. Clostridial infection should be considered in cases of postpartum gangrenous metritis of does.

Different groups of parasites (Helminths, Protozoa, Acarians and Insects) and the associated pathologies remain a main constraint on ruminant breeding. For decades, the control of these parasitic infections has mainly relied on synthetic antiparasitic drugs, developed and provided regu-larly by the pharmaceutical industry. However, this monolithic approach to control parasitism based on a quasi-exclusive reliance on chemical drugs is nowadays facing several limits. On the one hand, there is an increasing public demand to promote a more sustainable, agroecological agriculture aiming at lower chemical inputs. On the other hand, the phenomenon of resistance to antiparasitic drugs is an overall and constant process identified in the different groups of parasites. In this context, the new paradigm to control parasitic infections and their consequences in ruminants is based on the concept of integrated management combining different alternative solutions in addition to synthetic treatments. The aim of this review was to illustrate different alternative options, corresponding to different principles, based on 2 main parasitic models: gastro intestinal nematodes and insects affecting either small ruminants and/or cattle.

In dairy farms, new rearing practices of calves with nurse cows have been developed by farmers but still remain poorly documented. The objective was to assess the impact of rearing suckling calves with nurse cows on the same pastures on the risk of gastrointestinal nematode (GIN) infection in calves. The grazing management has been recorded for each group. Serum pepsinogen level and GIN egg excretion per gram of faeces (epg) were determined in 438 calves belonging to 38 groups from 30 farms in the western part of France at housing (October 2018 to January 2019). The maximum number of infective larval generations met by the animals (LG) in each pasture plot was modelled by Parasit’Sim expert system. The data were analyzed using logistic regression (univariate and multivariate). Mean parasiticological parameters per group were low. On average, the serum pepsinogen level was 1.1 units of tyrosine (U Tyr) and the GIN egg output was 130 epg. Pasture infectivity was above LG4 for 2/3 of the groups. These results suggest that rearing suckling dairy calves with nurse cows decreases the level of GIN infection in calves at the end of the 1st grazing season compared with putting out to pasture weaned heifers alone. This can be explained by i) the fact that cows were immune and have a cleansing effect on the pastures when eating a lot of larvae while excreting few eggs and ii) Because not weaned calves had a slow larval intake when drinking milk from nurse cows.

In young cattle, bovine respiratory disease (BRD) is a major cause of death and Mannheimia haemolytica is a frequent pathogen. Knowledge of fatal BRD in adult cattle is more limited. We assessed the importance of infectious BRD as a cause of death in adult cattle and determined the associated pathogens. We analyzed data from 737 adult cattle necropsies at the Pathology Unit for Large Animals at Oniris, Nantes, France over a 6 year period (2013–2019). Each carcass was subjected to a complete necropsy. Lungs showing macroscopic lesions were classified into three categories: infectious primary pulmonary (IPP) lesions, thromboembolic pneumonia (TEP) and others (aspiration pneumonia, verminous pneumonia, and local extension of an extra-pulmonary inflammatory process). Half of the lungs with IPP macroscopic lesions were sampled for histology and submitted for polymerase chain reaction. BRD was the second leading cause of death (15.7%) after digestive diseases (32.2%). A strong predominance of IPP lesions (42.3%) and TEP lesions (39.6%) was also demonstrated. In IPP macroscopic lesions, fibrinous, hemorrhagic and/or hecrotic (FHN) bronchopneumonia accounted for 77.6% of macroscopic lesions. Mannheimia haemolytica was significantly associated with FHN bronchopneumonia macroscopic lesions. This study suggests that Mannheimia haemolytica should be included in the differential diagnosis of BRD in adult cattle.

A questionnaire was distributed to 5487 farmers throughout Norway in order to obtain information about management practices regarding helminth infections in sheep. In addition, the farmers' perceptions of helminths and anthelmintic efficacy were investigated. Most farmers (80%) treated prophylactically against nematodes, and 24% also used prophylactic treatment against Fasciola hepatica. Overall, few farmers (11%) used parasitological analysis as a tool to assess the timing of treatment, but rather based it on other factors such as previous experience (70%). In the surveyed sheep flocks, the use of benzimidazoles was reduced from 2018 (52%) to 2019 (47%) (p < 0.01), whereas the use of macrocyclic lactones increased from 2017 (23%) to 2019 (36%) (p < 0.001). Poor anthelmintic efficacy was suspected by 10% of the farmers, and 11% reported that helminths were an increasing problem in their flocks. The majority of farmers (72%) considered their veterinarian as the most important advisor for treatment of parasites, but reported a high level of uncertainty regarding which parasites were present in their flocks, with unknown status most frequently reported for Haemonchus contortus (71.5%). This is probably related to the fact that very few farmers (15%) regularly test their animals for parasites. The present study provides up-to-date information on treatment practices for helminths in Norwegian sheep flocks.

La conduite des veaux laitiers avec des vaches nourrices est de plus en plus repandue, notamment en Agriculture Biologique, mais reste peu documentee : les descriptions zootechniques et l’impact de ce systeme sur la croissance et la sante des veaux sont peu connus. Les objectifs de cette etude etaient donc de decrire cette conduite et d’evaluer chez les veaux eleves sous nourrice les performances zootechniques ainsi que les risques parasitaires lies a la cryptosporidiose et aux strongyloses digestives, deux maladies majeures des jeunes ruminants. Cette etude a ete realisee dans 20 fermes biologiques pratiquant cette conduite. Les veaux restaient sous la mere durant 4,5 jours en moyenne, puis passaient, pour 57% d’entre eux, par une phase d’allaitement artificiel. L’adoption par une nourrice etait realisee en moyenne a 8 jours. Les feces de 611 veaux âges de 5 a 21 jours ont ete preleves de janvier a septembre 2019 pour detecter les oocystes de Cryptosporidium. La prevalence d’excretion de 40,2% etait similaire a celle trouvee chez des veaux eleves classiquement mais l’intensite d’excretion et la prevalence de diarrhee semblaient inferieures. Les facteurs de risque d’excretion identifies etaient soit non specifiques de cette conduite sous nourrices (ex : naissance en milieu ou fin de saison de velage vs debut de saison), soit en lien avec cette conduite (ex : phase d’allaitement ou d’adoption vs phase uniquement avec sa mere). Concernant la croissance et les strongyloses digestives, des pesees et des prelevements de feces et de sang ont ete realises a 4 reprises sur les 416 veaux gardes pour le renouvellement et leurs 197 nourrices au cours de la saison de pâturage. Les veaux avaient un GMQ eleve (en moyenne 783 grammes par jour) durant cette premiere saison de pâturage. L’ensemble des indicateurs concernant les strongles gastro-intestinaux (excretion fecale, pepsinogene sanguin, serologie Ostertagia, Parasit’Sim) ont montre une faible exposition parasitaire malgre une duree de pâturage longue (191 jours en moyenne). Ces resultats suggerent que le pâturage mixte vaches nourrices/veaux protegent ces derniers vis-a-vis des strongles gastro-intestinaux. Globalement sur la premiere annee de vie, la conduite de veaux laitiers avec des nourrices semble avoir un effet benefique sur la sante et la croissance des veaux.