Epidemiology of Gastrointestinal Nematodes in Grazing Yearling Beef Cattle in Saskatchewan
Notice bibliographique
Résumé
Gastrointestinal nematodes (GIN) in beef cattle can be a concern for cattle producers due to loss in profit associated with anthelmintic treatment costs and reduced production performance. There is limited current information regarding the epidemiology of GIN in grazing yearling beef cattle in western Canada. Hence, the objectives of this research were to: 1) describe the epidemiology of GIN and assess their impact on weight gain (Chapter 2), and 2) conduct a nemabiome study to determine the diversity and abundance of nematode species within Saskatchewan pastured beef cattle (Chapter 3). Seventeen cohorts of pastured yearling beef cattle were processed in the spring and fall of 2019. Animals were individually weighed, and rectal fecal samples obtained for pooled fecal egg count (FEC). A subset of calves (n = 25) in each herd was administered oral fenbendazole (Safeguard®, Merck, Canada) and a parenterally administered extended-release eprinomectin (LongRange®, Boehringer Ingelheim, Canada), while the remaining cohort was left untreated. Eggs per gram of feces (EPG) were determined in pooled fecal samples using the Modified Wisconsin Sugar Flotation Technique, and deep amplicon nemabiome sequencing of the ITS-2 DNA locus was used to describe nematode species diversity and abundance. Across all cattle (n = 867), there were differences between treatment and control groups regarding FEC (p < 0.01). In the generalized estimating equations (GEE) model, FEC decreased by 44 times over the grazing season, and FEC were 1.8 times greater on pastures located in black/gray soil versus dark brown soil zones. Areas with higher precipitation also had higher FEC. There was no significant difference (p = 0.41) in the ADG across all cattle, but differences were found in the ADG between treated and control cattle in five cohorts. Haemonchus placei was found in all spring cohorts, accounting for 30% of the L3 species composition. Hence, it was one of the dominant species together with Ostertagia ostertagi (40%) and Cooperia oncophora (26.2%). Ostertagia ostertagi (47.5%) and C. oncophora (42.0%) were the most common species recovered at the time of fall sampling. Haemonchus placei represented 5.2% of the species diversity at the time of fall sampling, which is higher than previously reported in western Canada. The lack of correlation between FEC and ADG is likely due to differences in farm-specific environmental conditions (rain, temperature), soil type and husbandry factors.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».