Integration of ITS-2 rDNA nemabiome metabarcoding with Fecal Egg Count Reduction Testing (FECRT) reveals ivermectin resistance in multiple gastrointestinal nematode species, including hypobiotic Ostertagia ostertagi, in western Canadian beef cattle.

A large-scale Fecal Egg Count Reduction Test (FECRT) was integrated with ITS-2 rDNA nemabiome metabarcoding to investigate anthelmintic resistance in gastrointestinal nematode (GIN) parasites in western Canadian beef cattle. The study was designed to detect anthelmintic resistance with the low fecal egg counts that typically occur in cattle in northern temperate regions. Two hundred and thirty-four auction market-derived, fall-weaned steer calves coming off pasture were randomized into three groups in feedlot pens: an untreated control group, an injectable ivermectin treatment group, and an injectable ivermectin/oral fenbendazole combination treatment group. Each group was divided into six replicate pens with 13 calves per pen. Individual fecal samples were taken pre-treatment, day 14 post-treatment, and at monthly intervals for six months for strongyle egg counting and metabarcoding. Ivermectin treatment resulted in an 82.4% mean strongyle-type fecal egg count reduction (95% CI 67.8-90.4) at 14 days post-treatment, while the combination treatment was 100% effective, confirming the existence of ivermectin-resistant GIN. Nemabiome metabarcoding of third-stage larvae from coprocultures revealed an increase in the relative abundance of Cooperia oncophora, Cooperia punctata, and Haemonchus placei at 14 days post-ivermectin treatment indicating ivermectin resistance in adult worms. In contrast, Ostertagia ostertagi third-stage larvae were almost completely absent from day 14 coprocultures, indicating that adult worms of this species were not ivermectin resistant. However, there was a recrudescence of O. ostertagi third stage larvae in coprocultures at three to six months post-ivermectin treatment, which indicated ivermectin resistance in hypobiotic larvae. The calves were recruited from the auction market and, therefore, derived from multiple sources in western Canada, suggesting that ivermectin-resistant parasites, including hypobiotic O. ostertagi larvae, are likely widespread in western Canadian beef herds. This work demonstrates the value of integrating ITS-2 rDNA metabarcoding with the FECRT to enhance anthelmintic resistance detection and provide GIN species- and stage-specific information.

Effects of naturally acquired gastrointestinal nematode infection on bovine viral diarrhea virus vaccine-directed antibody response in western Canadian feedlot cattle.

Objective: To determine how gastrointestinal nematode (GIN) infection, reflected by fecal egg counts and Ostertagia ostertagi serum antibody titers, is associated with the antibody response to bovine viral diarrhea virus type 1 (BVDV-1) vaccine antigen in fall-weaned feedlot cattle from western Canada. Animals: Cross-sectional study with 240 steer calves derived from an auction market. Procedure: At feedlot arrival, calves were given a commercial vaccine containing modified live BVDV-1. Serum neutralization antibody titers against BVDV-1 antigens were determined in individual blood samples collected pre-vaccination and 21 d after vaccination. A modified Wisconsin sugar floatation method was used to obtain individual calf GIN egg counts in fecal samples on arrival. Antibody titers against O. ostertagi were determined using an enzyme-linked immunosorbent assay in on-arrival blood samples. Results: Fecal egg counts and O. ostertagi titers were not associated with vaccine antibody-fold changes. Similarly, fecal egg counts and O. ostertagi titers were not associated with vaccine-induced seroconversion. Conclusions: The relatively low GIN burdens, reflected by the overall low fecal egg counts in these fall-weaned feedlot calves, did not have measurable adverse effects on the humoral immune response to BVDV-1 vaccine antigens. Clinical relevance: An adequate response to vaccination is important for cattle welfare and productivity. Conditions that negatively affect this response may vary regionally, such as GIN infection. Understanding this is essential. Although subclinical intestinal parasitism did not noticeably affect the antibody response in these steers, higher GIN burdens and actual immune protection from clinical disease remain to be investigated.

Effets d'une infection par des nématodes gastro-intestinaux d'origine naturelle sur la réponse en anticorps dirigés par le vaccin contre le virus de la diarrhée virale bovine chez les bovins des parcs d'engraissement de l'Ouest canadien. Objectif: Déterminer comment l'infection par les nématodes gastro-intestinaux (GIN), reflétée par le nombre d'oeufs fécaux et les titres d'anticorps sériques d'Ostertagia ostertagi, est associée à la réponse en anticorps à l'antigène du vaccin contre le virus de la diarrhée virale bovine de type 1 (BVDV-1) chez les bovins en parc d'engraissement sevrés à l'automne de l'Ouest canadien. Animaux: Étude transversale auprès de 240 veaux bouvillons issus d'un marché aux enchères. Procédure: À leur arrivée au parc d'engraissement, les veaux ont reçu un vaccin commercial contenant du BVDV-1 vivant modifié. Les titres d'anticorps sériques neutralisants contre les antigènes BVDV-1 ont été déterminés dans des échantillons de sang individuels prélevés avant la vaccination et 21 jours après la vaccination. Une méthode de Wisconsin modifiée de flottation au sucre a été utilisée pour obtenir le nombre d'oeufs GIN de chaque veau dans les échantillons fécaux à l'arrivée. Les titres d'anticorps dirigés contre O. ostertagi ont été déterminés à l'aide d'un dosage immuno-enzymatique dans des échantillons de sang à l'arrivée. Résultats: Le nombre d'oeufs fécaux et les titres d'O. ostertagi n'étaient pas associés aux modifications du titre d'anticorps vaccinaux. De même, le nombre d'oeufs fécaux et les titres d'O. ostertagi n'étaient pas associés à la séroconversion induite par le vaccin. Conclusion: Les charges relativement faibles de GIN, reflétées par le faible nombre global d'oeufs fécaux chez ces veaux d'engraissement sevrés à l'automne, n'ont pas eu d'effets indésirables mesurables sur la réponse immunitaire humorale aux antigènes du vaccin BVDV-1. Pertinence clinique: Une réponse adéquate à la vaccination est importante pour le bien-être et la productivité des bovins. Les conditions qui affectent négativement cette réponse peuvent varier selon les régions, telles que l'infection par les GIN. Comprendre cela est essentiel. Bien que le parasitisme intestinal subclinique n'ait pas sensiblement affecté la réponse en anticorps chez ces bouvillons, des charges de GIN plus élevées et une protection immunitaire réelle contre la maladie clinique restent à étudier.(Traduit par Dr Serge Messier).

Regional heterogeneity and unexpectedly high abundance of Cooperia punctata in beef cattle at a northern latitude revealed by ITS-2 rDNA nemabiome metabarcoding.

BACKGROUND: The species composition of cattle gastrointestinal nematode (GIN) communities can vary greatly between regions. Despite this, there is remarkably little large-scale surveillance data for cattle GIN species which is due, at least in part, to a lack of scalable diagnostic tools. This lack of regional GIN species-level data represents a major knowledge gap for evidence-based parasite management and assessing the status and impact of factors such as climate change and anthelmintic drug resistance. METHODS: This paper presents a large-scale survey of GIN in beef herds across western Canada using ITS-2 rDNA nemabiome metabarcoding. Individual fecal samples were collected from 6 to 20 randomly selected heifers (n = 1665) from each of 85 herds between September 2016 and February 2017 and 10-25 first season calves (n = 824) from each of 42 herds between November 2016 and February 2017. RESULTS: Gastrointestinal nematode communities in heifers and calves were similar in Alberta and Saskatchewan, with Ostertagia ostertagi and Cooperia oncophora being the predominant GIN species in all herds consistent with previous studies. However, in Manitoba, Cooperia punctata was the predominant species overall and the most abundant GIN species in calves from 4/8 beef herds. CONCLUSIONS: This study revealed a marked regional heterogeneity of GIN species in grazing beef herds in western Canada. The predominance of C. punctata in Manitoba is unexpected, as although this parasite is often the predominant cattle GIN species in more southerly latitudes, it is generally only a minor component of cattle GIN communities in northern temperate regions. We hypothesize that the unexpected predominance of C. punctata at such a northerly latitude represents a range expansion, likely associated with changes in climate, anthelmintic use, management, and/or animal movement. Whatever the cause, these results are of practical concern since C. punctata is more pathogenic than C. oncophora, the Cooperia species that typically predominates in cooler temperate regions. Finally, this study illustrates the value of ITS-2 rDNA nemabiome metabarcoding as a surveillance tool for ruminant GIN parasites.

Morphometric, metabolic, and inflammatory markers across a cohort of client-owned horses and ponies on the insulin dysregulation spectrum.

In human metabolic syndrome and type II diabetes, methylglyoxal (MG), D-lactate, and several cytokines have been recognized as biomarkers of important metabolic and inflammatory processes. Equine metabolic syndrome (EMS) shares many similarities with these human counterparts. The objectives of this cross-sectional study were to compare body condition score (BCS), cresty neck score (CNS), resting insulin, MG, D-lactate, L-lactate, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) between horses with and without insulin dysregulation, as classified via combined glucose and insulin test (CGIT). 32 client-owned horses were included. History and morphometric data such as BCS and CNS were recorded. Subjects with abnormalities on physical examination or CBC, elevated ACTH or incomplete information were excluded. Baseline serum or plasma concentrations of biomarkers were tested via commercial ELISA or colorimetric assays. Characteristics of insulin dysregulated and insulin sensitive horses were compared by univariate analysis and forward logistic regression. 12 (38%) of the 32 horses were classified as insulin dysregulated. No significant difference between the 2 groups was found for age, BCS, baseline glucose, triglycerides, MG, D-lactate, L-lactate, TNF-α, IL-6, and MCP-1. Baseline insulin was significantly associated with insulin dysregulation in univariate analysis (P = 0.02), but not in the final model. Horses with CNS ≥ 3 had 11.3 times higher odds of having insulin dysregulation (OR 11.3, 95% C.I. 2.04 - 63.08, P = 0.006). In this population, horses with mild-moderate signs of EMS presented similar metabolic and inflammatory profiles to non-insulin dysregulated controls.

Pharmacokinetics and pharmacodynamics of doxycycline in a Streptococcusequi subsp. zooepidemicus infection model in horses.

The objectives of this study were to investigate the pharmacokinetics (PK), pharmacodynamics (PD), and the efficacy of oral administration of doxycycline (DXC) in horses with Streptococcus zooepidemicus tissue infections. Tissue chambers (TC) were implanted subcutaneously in the cervical region of 7 horses and inoculated with a single S. zooepidemicus isolate with a minimum inhibitory concentration (MIC) of 0.25 µg/ml, determined by agar dilution. Doxycycline hyclate (10 mg/kg, orally, q 12 h, for 5 days) mixed with poloxamer gel was started following inoculation. The TC fluid was sampled prior to and following inoculation for cytology analysis, quantitative culture, and DXC determination. Plasma DXC concentrations were measured over 48 h following the last dose of DXC administered. The mean plasma peak concentration (Cmax ) of DXC was 0.32 µg/ml, and concentrations above the MIC were only reached in 3 TC samples. In plasma, mean T > MIC was 2.4 h, mean Cmax /MIC was 1.30, and mean AUClast /MIC was 11.63 h. These PK/PD indices did not reach the suggested targets for DXC treatments of infections, and the TC abscessed in all horses. This is the first study to evaluate the recommended dose of DXC in horse in an infection model.

The use of ITS-2 rDNA nemabiome metabarcoding to enhance anthelmintic resistance diagnosis and surveillance of ovine gastrointestinal nematodes.

A lack of quantitative information on the species composition of parasite communities present in fecal samples is a major limiting factor for the sensitivity, accuracy and interpretation of the diagnostic tests commonly used to assess anthelmintic efficacy and resistance. In this paper, we investigate the ability of ITS-2 rDNA nemabiome metabarcoding to enhance fecal egg count reduction testing by providing information on the effect of drug treatments on individual parasite species. Application of ITS-2 rDNA nemabiome metabarcoding to fecal samples from ewes from over 90 flocks across western Canada revealed high gastrointestinal nematode infection intensities in many flocks with Haemonchus contortus being the most abundant species followed by Teladorsagia circumcincta and then Trichostrongylus colubriformis. Integration of ITS-2 rDNA nemabiome metabarcoding with pre- and post-treatment fecal egg counting revealed consistently poor efficacy of producer-applied ivermectin and benzimidazole treatments against H. contortus, but much better efficacy against T. circumcincta and T. colubriformis, except for in a small number of flocks. Integration of nemabiome ITS-2 rDNA metabarcoding with Fecal Egg Count Reduction Tests (FECRT), undertaken on farm visits, confirmed that ivermectin and fenbendazole resistance is widespread in H. contortus but is currently less common in T. circumcincta and T. colubriformis in western Canada. FECRT/nemabiome testing did not detect moxidectin resistance in any GIN species but suggested the early emergence of levamisole resistance specifically in T. circumcincta. It also revealed that although poor efficacy to closantel was relatively common, based on total fecal egg counts, this was due to its narrow spectrum of activity rather than the emergence of anthelmintic resistance. This study illustrates the value of ITS-2 rDNA nemabiome metabarcoding to improve fecal egg count resistance testing, perform large-scale anthelmintic resistance surveillance and direct more targeted rational anthelmintic use.

Septic fibrinous pericarditis in 4 horses in Saskatchewan following an outbreak of forest tent caterpillars in 2017.

In the summer of 2017, 4 horses were diagnosed with septic fibrinous pericarditis at the Western College of Veterinary Medicine, Saskatoon. This case series occurred after a significant outbreak of forest tent caterpillars (Malacosoma disstria) in the province during that spring. Three horses were immediately euthanized, and treatment was attempted in 1 mare. This is the first case series of pericarditis possibly associated with the ingestion of forest tent caterpillars to be reported in western Canada. Although cause-effect is not proven, it is prudent to prevent the ingestion of caterpillars by horses. Key clinical message: Septic fibrinous pericarditis, a rare condition in horses, has previously been linked to outbreaks of eastern tent caterpillars. A similar link might exist in this case series.

Péricardites fibrineuses septiques chez quatre chevaux saskatchewanais consécutive à une infestation de chenilles de livrée des forêts en 2017. Au cours de l'été 2017, quatre chevaux ont été diagnostiqués avec une péricardite fibrineuse septique au Western College of Veterinary Medicine de Saskatoon. Ces cas ont été présentés après une sévère infestation printanière de chenilles de livrée de forêts (Malacosoma disstria) dans la province de la Saskatchewan, reportée au printemps. Trois chevaux ont été immédiatement euthanasiés et une jument a été hospitalisée pour traitement. Ceci est le premier rapport décrivant la possible association entre des cas de péricardite chez des chevaux et l'ingestion de chenilles de livrée de forêts dans l'Ouest canadien. Même si le lien de cause à effet n'est pas prouvé, il est prudent d'éviter l'ingestion de ces chenilles processionnaires par les chevaux.Message clinique clé :La péricardite fibrineuse septique, une condition rare chez les chevaux, a précédemment été liée à des flambées de livrées des forêts. Un lien similaire pourrait exister dans la présente série de cas.(Traduit par les auteurs).

Gastrointestinal nematode prevalence and fecal egg counts in beef cattle from western Canada.

Fecal samples were collected from cows (n = 1458), calves (n = 1188), and replacement heifers (n = 921) between 2012 and 2014 from 199 herds and generalized estimating equations were used to predict mean fecal egg counts and prevalence of egg-positive samples. Replacement heifers had the highest prevalence of Trichostrongylid-type eggs at 83% [95% confidence interval (CI): 78% to 87%], and cows had the lowest at 75% (95% C: 70% to 81%). Nematodirus spp. was most frequently present in calves [predicted prevalence: 34% (95% CI: 28% to 40%)]. Mean fecal egg counts were highest in calves with 5.9 (95% CI: 3.9 to 7.8) Trichostrongylid-type eggs per gram (EPG) of feces and 1.0 (95% CI: 0.7 to 1.4) Nematodirus spp. EPG. Although mean egg counts were low to moderate, the high prevalence highlights the need to further investigate the epidemiology of gastrointestinal nematodes in western Canada. This is particularly relevant considering management changes, increasing herd sizes, climate change, and threatening anthelmintic resistance.

Prévalence des nématodes gastro-intestinaux et dénombrements des oeufs dans les fèces chez les bovins d'embouche dans l'ouest canadien. Des échantillons de fèces furent prélevés de vaches (n = 1458), veaux (n = 1188) et génisses de remplacement (n = 921) entre 2012 et 2014 dans 199 troupeaux et des équations d'estimation généralisée furent utilisées pour prédire les dénombrements moyens d'oeufs dans les fèces et la prévalence d'échantillons positifs pour la présence d'oeufs. Les génisses de remplacement avaient la prévalence la plus élevée d'oeufs de type Trichostrongylide avec 83 % [intervalle de confiance 95 % (IC) : 78 % à 87 %], et les vaches avaient la plus faible avec 75 % (95 % IC : 70 % à 81 %). Les Nematodirus spp. étaient présents le plus fréquemment chez les veaux [prévalence prédite : 34 % (95 % IC : 28 % à 40 %)]. Les dénombrements moyens d'oeufs dans les fèces étaient les plus élevés chez les veaux avec 5,9 (95 % IC : 3,9 à 7,8) oeufs de type Trichostrongylide par gramme (EPG) de fèces et 1,0 (95 % IC : 0,7 à 1,4) EPG de Nematodirus spp. Bien que les dénombrements moyens d'oeufs étaient faibles à modérés, la prévalence élevée met en évidence le besoin de continuer d'examiner l'épidémiologie des nématodes gastro-intestinaux dans l'ouest du Canada. Ceci est particulièrement approprié considérant les changements dans la gestion, l'augmentation de la taille des troupeaux, les changements climatiques et la menace de la résistance aux produits anthelmintiques.(Traduit par Dr Serge Messier).

Gastrointestinal nematode management in western Canadian cow-calf herds.

There is a paucity of information from western Canadian beef cow-calf producers about how they control gastrointestinal nematodes. The objectives of this study were to describe cow-calf producers' management practices related to control of gastrointestinal nematodes including pasture management and use of parasite control products. A questionnaire was distributed to 105 producers in May 2015. Responses from 97 producers revealed the almost uniform dependence on the use of a pour-on macrocyclic lactone parasite control product in the fall as part of a routine farm management program. Control of external parasites was the primary reason for treatment, while none of the producers chose to treat specifically to manage internal parasites. The predominant management practices identified through this study increase the risk of development of anthelmintic resistance. The results also highlight the need to raise awareness of the importance of an evidence-based gastrointestinal nematode control program in beef cow-calf herds.

Gestion des nématodes gastro-intestinaux dans les troupeaux vaches-veaux de l'ouest canadien. Il y a une rareté d'informations provenant des producteurs de vaches-veaux de l'ouest canadien sur la façon dont ils maitrisent les nématodes gastro-intestinaux. Les objectifs de la présente étude étaient de décrire les pratiques de gestion des producteurs de vaches-veaux relativement à la maitrise des nématodes gastro-intestinaux incluant la gestion des pâturages et l'utilisation des produits antiparasitaires. Un questionnaire fut distribué à 105 producteurs en mai 2015. Des réponses en provenance de 97 producteurs ont révélé la dépendance presque généralisée sur l'utilisation d'un produit antiparasitaire à verser sur l'animal à base de lactone macrocyclique à l'automne comme faisant partie d'un programme de routine de gestion à la ferme. La maitrise des parasites externes était la principale raison pour le traitement, alors qu'aucun des producteurs n'avait choisi de traiter spécifiquement pour gérer les parasites internes. Les pratiques de gestion prédominantes identifiées dans la présente étude augmentent le risque de développement de résistance aux anthelmintiques. Les résultats mettent également en lumière le besoin d'augmenter la sensibilisation de l'importance d'une approche factuelle à un programme de gestion des nématodes dans les troupeaux vaches-veaux.(Traduit par Dr Serge Messier).

Survey of gastrointestinal nematodes in breeding-age heifers on 6 Saskatchewan dairy farms.

To determine the prevalence, mean fecal egg count intensities, and predominant gastrointestinal nematode species, fresh environmental fecal samples were collected from 30 grazing heifers at monthly intervals (June, July, and August) on 6 Saskatchewan dairy farms in 2016. The population average strongylid prevalence ranged from 67.2% [95% confidence interval (CI): 49.5% to 84.9%] in June to 88.3% (95% CI: 76.7% to 100.0%) in August (P = 0.05) while the mean fecal egg count ranged from 1.7 in June to 9.3 eggs/g of feces in August (P < 0.003). The predominant nematode species were identified using a deep-sequencing nemabiome assay targeting the internal transcribed spacer rDNA genomic locus of both L1 and L3-stage larvae. Cooperia oncophora and Ostertagia ostertagi were predominant on all farms, accounting for > 85% of the species. The results provide important previously unavailable data on the epidemiology of gastrointestinal nematodes (GIN) in fecal samples from these grazing heifers in Saskatchewan.

Examen des nématodes gastro-intestinaux chez les génisses en âge de se reproduire sur six fermes laitières de la Saskatchewan. Afin de déterminer la prévalence, l'intensité du dénombrement moyen d'oeufs dans les fèces et les espèces de nématodes gastro-intestinaux prédominants, des échantillons environnementaux de fèces fraîches furent prélevés de 30 génisses au pâturage à un intervalle mensuel (juin, juillet, et août) sur six fermes laitières de la Saskatchewan en 2016. La prévalence de la population moyenne de strongyles variait de 67,2 % [intervalle de confiance de 95 % (CI) : 49,5 % à 84,9 %] en juin à 88,3 % (CI 95 % : 76,7 % à 100,0 %) en août (P = 0,05) alors que le dénombrement moyen des oeufs dans les fèces variait de 1,7 en juin à 9,3 oeufs/g de fèces en août (P < 0,003). Les espèces de nématodes prédominantes furent identifiées à l'aide d'un test de séquençage profond du némabiome visant l'ADNr du locus génomique de l'espaceur interne transcrit des stades larvaires L1 et L3. Cooperia oncophora et Ostertagia ostertagi étaient prédominants sur toutes les fermes, représentant > 85 % des espèces. Ces résultats fournissent des données importantes non-disponibles auparavant sur l'épidémiologie de GIN dans des échantillons de fèces provenant de ces génisses au pâturage en Saskatchewan.(Traduit par Dr Serge Messier).

Investigation of a Yersinia enterocolitica outbreak in a commercial alpaca farm in Saskatchewan.

An outbreak of enterocolitis and sudden deaths occurred in an alpaca herd in Saskatchewan (mortality rate: 18.6%). Yersinia enterocolitica was isolated from the intestine, liver, and spleen of the index case, the kidney of a second case, and the feces of affected animals. The initial source of infection could not be identified. Treatment with oxytetracycline was followed by resolution of diarrhea and arrest of fatalities. The end of the outbreak was determined by absence of new cases and negative fecal cultures. This is the first report of a presumed herd outbreak of yersiniosis in camelids in North America.

Enquête à la suite d'une épidémie due à Yersinia enterocolitica dans une ferme commerciale d'alpagas en Saskatchewan. Une épidémie d'entérocolite et de mortalités soudaines est survenue dans un troupeau d'alpaga en Saskatchewan (taux de mortalité : 18,6 %). Yersinia enterocolitica fut isolé à partir de l'intestin, du foie et de la rate du cas index, du rein d'un second cas, et des fèces des animaux affectés. La source initiale d'infection ne put être identifiée. Un traitement avec de l'oxytétracycline fut suivi d'une résolution de la diarrhée et un arrêt des mortalités. La fin de l'épidémie fut déterminée par l'absence de nouveaux cas et des cultures de fèces négatives. Ceci constitue le premier rapport d'une épidémie présumée de yersiniose chez des camélidés en Amérique du Nord.(Traduit par Dr Serge Messier).

Endoparasite control practices on Saskatchewan dairy farms.

A questionnaire was administered to dairy producers in Saskatchewan in 2016 to determine basic pasture management practices, how producers use parasite control products, and attitudes towards the threat of endoparasites. All 161 dairy producers in Saskatchewan were invited to participate and the survey response rate was 39.8% (64/161). Most respondents (78.3%) were not concerned with endoparasites in their cattle or the threat of anthelmintic resistance. Yet 79.7% of producers reported using anthelmintics in all classes of cattle (lactating cows, dry cows, weaned heifers, and bred heifers). The most common reasons for using an anthelmintic product were as part of a routine management strategy and for the control of external parasites. The most common method to determine dosage was by visual estimation of the animal's weight. Together, these factors may increase the risk for development of anthelmintic resistance.

Pratiques de contrôle des endoparasites dans les fermes laitières de la Saskatchewan. Un questionnaire a été administré aux producteurs laitiers de la Saskatchewan en 2016 afin de déterminer les pratiques de gestion de base du pâturage, comment les producteurs utilisaient les produits de lutte contre les parasites et les attitudes envers la menace des endoparasites. Tous les 161 producteurs laitiers de la Saskatchewan ont été invités à participer et le taux de réponse au sondage a été de 39,8 % (64/161). La plupart des répondants (78,3 %) ne se préoccupaient pas des endoparasites chez leur bétail ni de la menace de la résistance aux anthelminthiques. Pourtant 79,7 % des producteurs ont signalé qu'ils utilisaient des anthelminthiques dans toutes les catégories de bétail (vaches en lactation, vaches taries, génisses sevrés et génisses accouplées). Les raisons les plus communes pour l'utilisation du produit anthelminthique était dans le cadre d'une stratégie de gestion routinière et pour limiter les parasites externes. La méthode la plus commune de déterminer la posologie était l'estimation visuelle du poids de l'animal. Ensemble, ces facteurs peuvent accroître le risque du développement de la résistance aux anthelminthiques.(Traduit par Isabelle Vallières).

The One Health Leadership Experience at the University of Saskatchewan, Canada.

Competency in One Health (OH) leadership was emphasized in the Roadmap for Veterinary Medical Education in the 21st Century in 2011. Since then, several educational interventions have been aimed at increasing awareness and capacity for inter-professional collaboration. At the University of Saskatchewan, Canada, a 3-day event, the One Health Leadership Experience (OHLE), was initiated in 2012 and continues to the present. The event targets students entering their first year of a health professional program and consists of presentations by invited OH guest speakers, networking sessions, small-group case discussions of OH scenarios, and leadership development through panel discussions and interactive small-group dialogues. Post-conference surveys, a 5-year follow-up survey, and two focus groups were conducted to evaluate the impact of participation in the OHLE. After the event, the proportion of students who said they clearly understood OH and its goals was substantially higher than before: 86% versus 14% in 2012, 91% versus 23% in 2013, and 69% versus 24% in 2014. In the 5-year follow-up survey, most respondents (90%) indicated that attending the OHLE increased their interaction with other students from health sciences colleges or schools on campus. Also, most (81%) believed that OH should be formally taught in their program and 80% anticipated implementing, or had already implemented, OH practices after graduation. The OHLE increased participants' awareness of the importance of interdisciplinary approaches and is a successful educational model that can be adapted to health professional curricula at other institutions.

Prevalence of Mycobacterium avium ssp. paratuberculosis infections in Canadian dairy herds.

Johne's disease is a progressive, chronic disease with inflammation of the small intestine of ruminants caused by Mycobacterium avium ssp. paratuberculosis (MAP). Accurately estimating prevalence of MAP infections is important when controlling spread of infection or monitoring effectiveness of control programs. In the absence of a consistent test method used in prevalence studies across Canada, prevalence estimates among regions and programs cannot be compared. The aim of the current study was to estimate and compare prevalence of MAP infection in Western Canada, Ontario, Québec, and the Atlantic provinces, as well as among varying herd sizes and housing types. On 362 dairy farms located in all 10 provinces of Canada, environmental samples were collected and cultured for detection of MAP. For each herd, 1 sample was collected from the lactating cow area and manure storage. An additional environmental sample was collected from the area where breeding-age heifers were housed. Using prior distributions from previous research, diagnostic sensitivity and specificity were calculated to assess the ability of only 2 environmental samples (manure storage and lactating cow area) to identify MAP-positive farms, resulting in a sensitivity and specificity of 38 and 100%, respectively. We found no difference in sensitivity and specificity when including breeding-age heifers environmental samples. Test characteristics were applied to environmental culture results from the 362 participating farms in all 4 regions, resulting in true prevalence estimates of 66% for farms in Western Canada, 54% in Ontario, 24% in Québec, and 47% in Atlantic Canada. Herds housed in tiestalls had lower prevalence than freestall-housed herds, and herds with 101-150 and >151 cows had higher prevalence than herds with ≤100 cows. This was the first time MAP prevalence was determined using 1 detection method, performed in 1 laboratory, and within a single year across Canada, enabling direct comparisons of prevalence among regions, housing types, and herd sizes.

Canadian National Dairy Study: Heifer calf management.

In the past decade, substantial changes have occurred in the way dairy heifer calves are managed. The objectives of this study, part of phase I of the 2015 Canadian National Dairy Study, were to examine heifer calf health and adoption of rearing practices, and to explore factors associated with different rearing strategies on Canadian dairy farms. The questionnaire was open to all licensed dairy producers in Canada and had a 12% response rate (n = 1,373). Fifty-one percent of respondents reported never allowing heifer calves to nurse their dam, and 17% always removed calves within 30 min of birth. Sixty-seven percent reported always feeding heifer calves 4 L of colostrum within 12 h of birth; 17% always fed colostrum between 2100 and 0400 h; 5% pasteurized all colostrum fed on farm. Seventy-seven percent of respondents reported calving and stillbirth information for 2014; the mean reported stillbirth rate was 4.9% (SD = 3.3). Forty percent housed calves in individual pens, 34% in group pens, 21% in individual hutches, 2% reported tethering calves, and 1% used group hutches. Of those who housed calves in groups, 59% reported a maximum group size of 3 to 10 calves, 31% reported a pair (2) of calves per pen or hutch, and 10% reported a group >10 calves. The maximum amount of milk offered to calves per day during the preweaned period was a mean of 8 L (SD = 3). Fifty percent of respondents reported mortality data for 2014; mean preweaning mortality was 6.4% (SD = 8.3), and postweaning mortality was 2.4% (SD = 4.4). Over 95% of producers reported disbudding practices; 86% used cautery, 11% used surgical amputation, and 9% used caustic paste. Twenty-eight percent reported disbudding at less than 3 wk of age, 60% at 3 to 8 wk, and 22% at 8 to 16 wk; 5% of respondents reported dehorning at more than 16 wk of age. Sixty-six percent of cautery users reported use of local anesthetic, 33% used sedation, and 25% used a nonsteroidal anti-inflammatory drug (NSAID). Multivariable regression models showed that the use of local anesthetic when disbudding calves was associated with social media activity (odds ratio = 2.3) and high-speed internet access (odds ratio = 2.0), whereas sedation was associated with geographic region, and NSAID use was associated with disbudding at more than 3 wk of age. Exploring heifer rearing management practices, including adoption of best practices, may help focus future education and extension efforts. Poor reporting of mortality data may reflect a lack of recordkeeping on farm.

Observations of mortality in farmed bison in the Canadian prairies: 2103 - 2016.

The present study is a continuation of a previous mortality study on Saskatchewan bison farms with special emphasis on Malignant Catarrhal Fever. The updated objective of the study was to estimate the most common causes of mortality in farmed bison herds in Western Canada. Results were compared to the previous Saskatchewan study to assess the similarities and differences in the etiology associated with farmed bison deaths across the Prairie Provinces of Canada. The most common cause of death was respiratory disease associated with Mycoplasma bovis, although this was restricted to Alberta and Saskatchewan farm locations. This was in contrast to the previous Saskatchewan based study which did not identify any deaths involving this pathogen. An updated overall assessment of the risks of Malignant Catarrhal Fever in farmed bison at various proximities to sheep operations further confirmed the low risk of occurrence on farms within a 1 km boundary fence distance.

Seroprevalence of Cache Valley virus and related viruses in sheep and other livestock from Saskatchewan, Canada.

Cache Valley virus, an orthobunyavirus, is an important cause of ovine neonatal malformations. Information on the seroprevalence of this virus in Saskatchewan livestock populations is lacking. The objectives of this study were to determine the seroprevalence of Cache Valley virus and closely related viruses in sheep, cattle, goats, horses, and mule deer in Saskatchewan by performing a plaque-reduction neutralization test using Cache Valley virus. In total, sera from 130 sheep from 50 flocks were tested. Seroprevalence in sheep was 64.6% (84/130) and 94.0% (47/50) of flocks had 1 or more seropositive sheep. Antibodies to Cache Valley virus or closely related viruses were also detected in serum samples collected from cattle, goats, horses, and mule deer with seroprevalences of 20.0% (5/25), 33.3% (8/24), 69.0% (40/58), and 50.8% (33/65), respectively. These results suggest widespread exposure to Cache Valley virus or closely related viruses in domestic animals and mule deer in Saskatchewan.

Séroprevalence du virus de la Vallée Cache ou de virus connexes chez les moutons et d'autres animaux de cheptel en Saskatchewan, Canada. Le virus de la Vallée Cache, un orthobunyavirus, est une cause importante de malformations néonatales ovines. Il manque des renseignements sur la séroprévalence de ce virus dans les populations des cheptels de la Saskatchewan. Les objectifs de cette étude consistaient à déterminer la séroprévalence du virus de la Vallée Cache et des virus étroitement apparentés chez les moutons, les bovins, les chèvres, les chevaux et les cerfs mulets en Saskatchewan en réalisant un test de séro-neutralisation par réduction des plages en utilisant le virus de la Vallée Cache. Au total, le sérum provenant de 130 moutons dans 50 troupeaux a été testé. Chez les moutons, la séroprévalence était de 64,6 % (84/130) et 94,0 % (47/50) des troupeaux avaient un mouton ou plusieurs moutons séropositifs. Les anticorps pour le virus de la Vallée Cache ou les virus étroitement apparentés ont aussi été détectés dans les échantillons de sérum prélevés auprès des bovins, des chèvres, des chevaux et des cerfs mulets avec une séroprévalence de 20,0 % (5/25), de 33,3 % (8/24), de 69,0 % (40/58) et de 50,8 % (33/65), respectivement. Ces résultats suggèrent une vaste exposition au virus de la Vallée Cache ou à des virus étroitement apparentés chez les animaux domestiques et les cerfs mulets en Saskatchewan.(Traduit par Isabelle Vallières).

Comparison of five diagnostic tests for Giardia duodenalis in fecal samples from young dogs.

Five diagnostic tests were compared for the diagnosis of Giardia duodenalis in fecal samples of young dogs. Fecal samples were collected from 136 healthy dogs <1year old and examined using immunofluorescence antibody microscopy (IFA) after sucrose gradient centrifugation, zinc sulfate centrifugal flotation technique (ZSCT), SNAP®Giardia test, and ProSpecT®Giardia EZ Microplate assay. In addition, polymerase chain reaction (PCR) of the 16S rRNA gene was performed. Kappa (κ) statistic was calculated to assess diagnostic agreement between the IFA and each test. Using the IFA as the gold standard, the relative sensitivity and specificity of each test were determined. Subsequently, a Bayesian approach was used to estimate the sensitivity and specificity of each test in comparison to the IFA results. Giardia duodenalis was detected in 41% of the samples examined by IFA. The ZSCT resulted in 37% of positive samples, with a relative sensitivity and specificity of 86 and 98%, respectively. The SNAP®Giardia test was positive in 40% of the samples, with a relative sensitivity and specificity of 91 and 96%, respectively. The ProSpecT® test was positive in 51% of the samples, with a relative sensitivity and specificity of 100 and 83%, respectively. The relative sensitivity and specificity for PCR were 58 and 56%, respectively, with 55% of samples being PCR-positive. While the sensitivity and specificity estimates of each test in comparison to the IFA changed when using a Bayesian approach, the conclusions remained the same. While the ProSpecT® test was the most sensitive test in this study, it is not designed for dogs and more costly than the other tests. The SNAP®Giardia test performed similar to the ZSCT but may be more favorable because it is fast and easy to perform. Performance of the PCR was poor and the benefit of PCR may be in determining genotypes for evaluating zoonotic transfer between dogs and humans.

Randomized controlled trial on impacts of dairy meal feeding interventions on early lactation milk production in smallholder dairy farms of Central Kenya.

There is limited field-based research and recommendations on the effect of cattle feeding management practices on smallholder dairy farms (SDF) for the growing dairy industry in Kenya. This controlled trial aimed to determine the effect of feeding locally produced dairy meal (DM) on early lactation daily milk production (DMP) on Kenyan SDF, controlling for other factors associated with DMP. Privately owned, recently calved cows (n=111) were randomly assigned to one of three groups of feeding recommendations for DM (meeting predicted DM requirements by: (1) 100%; (2) 50%; or (3) feeding by the farmer's discretion). DM was provided for free to groups 1 and 2 to ensure they had sufficient DM to feed to the recommendations. Data collection on cow and farm characteristics occurred biweekly for a 60-day period post-calving starting in June 2013. A repeated measures multivariable linear regression model was used on the DMP outcome variable. With variability in DM consumption within feeding groups due to variability in DMP, actual DM fed was assessed as an independent variable rather than assigned feeding groups. DMP was positively associated with each kg/day of DM fed (0.53kg/day), cow weight (0.13kg/day), feeding DM in the month prior to calving (1.42kg/day), and feeding high protein forage (0.41kg/day), and was negatively associated with having mastitis (-0.30kg/day). In interaction terms, taller cows had higher DMP than shorter cows, whereas heifers (first parity cows) had similar DMP regardless of height. Also, thin cows (2+ parity with body condition score<2.5 out of 5) produced less milk (1.0kg/day less) than cows with a better body condition score at calving,whereas thin heifers produced more milk (2.0kg/day more) than heifers in better body condition-this association is possibly due to a small unrepresentative sample size of heifers. In conclusion, feeding DM in the month prior to calving, improving body condition in cows prior to calving, and enhancing dietary DM and high protein forage were positively associated with DMP in early lactation on Kenyan SDF. In addition there was an association between, taller cows and increased DMP, evidence supporting the importance of educating farmers on good genetic selection and heifer management. These findings will help with future management recommendations for higher DMP on SDF.

Associations of farm management practices with annual milk sales on smallholder dairy farms in Kenya.

AIM: Cows on smallholder dairy farms (SDF) in developing countries such as Kenya typically produce volumes of milk that are well below their genetic potential. An epidemiological study was conducted to determine reasons for this low milk production, including limited use of best management practices, such as suboptimal nutritional management. METHODS: An observational cross-sectional study of 111 SDF was performed in Nyeri County, Kenya in June of 2013 determining the effect of cow factors, farmer demographics and farm management practices on the volume of milk sold per cow per year (kg milk sold/cow). In particular, the effect of feeding high protein fodder trees and other nutritional management practices were examined. RESULTS: Approximatly 38% of farmers fed fodder trees, but such feeding was not associated with volume of milk sold per cow, likely due to the low number of fodder trees per farm. Volume of milk sold per cow was positively associated with feeding dairy meal during the month prior to calving, feeding purchased hay during the past year, deworming cows every 4 or more months (as opposed to more regularly), and having dairy farming as the main source of family income. Volume of milk sold per cow was negatively associated with a household size of >5 people and feeding Napier grass at >2 meters in height during the dry season. An interaction between gender of the principal farmer and feed shortages was noted; volume of milk sold per cow was lower when female farmers experienced feed shortages whereas milk sold per cow was unaffected when male farmers experienced feed shortages. CONCLUSIONS: These demographic and management risk factors should be considered by smallholder dairy farmers and their advisors when developing strategies to improve income from milk sales and animal-source food availability for the farming families.