PSX-27 Growth performance and immune response dynamics in weaned lambs with subclinical <i>Haemonchus contortus</i> parasite infection
Notice bibliographique
Résumé
Abstract Parasite infections, particularly from Haemonchus contortus, hinder sheep production in Canada by reducing weight gain and immunity. Current diagnosis and treatment methods rely on observing symptoms and the blind administration of anthelmintic drugs, resulting in escalating costs and the development of drug-resistant parasites. This study aimed to identify the exact time-point when subclinical H. contortus parasite infection affects growth performance and triggers an immune response. A total of 60 Rideau Arcott ewe lambs (~7-8 mo old), confirmed to be parasite-free, were randomly assigned in a 2 x 2 factorial design assessing inoculation treatment (TRT): oral inoculation (IN) with a solution containing 5,000 L3 strain of H. contortus or sham inoculation (CT) using water solution as control; and drench (DRENCH) administration: oral drench (D), 28-days post-inoculation, with a combination of 0.08% ivermectin solution (200 mcg per kg of BW; Durvet®) and 10% oral suspension of fenbendazole (2.5 mL per 50 kg of BW; Safe-guard®), or water solution (non-drenched, ND), resulting in four treatment groups: IN-D, IN-ND, CT-D, and CT-ND (n=15/treatment). Lambs were equally assigned to four feedlot pens (two replicates/treatment) for 57 days (d) with ad libitum access to a grain-based total mixed ration and water. Animals were individually weighed (BW) and blood sampled on days -1 and 0 (baseline), as well as on days 7, 21, 28, 35, 42, 56, and 57 post-inoculations (DAY); average daily gain (ADG) was calculated for the entire experimental period. White blood cells count (WBC) was used as an indicator of infection and red blood cell count (RBC) as indicator of anemia. Data was analyzed using a mixed-effects model including TRT, DRENCH, DAY (and their interactions) as fixed effects. Overall, CT lambs were heavier (TRT effect; P &lt; 0.05) and had a tendency of greater (TRT effect; P = 0.08) ADG than IN lambs. The IN lambs had a tendency of greater (TRT*DAY; P = 0.07) WBC on d 7 than CT lambs. Additionally, IN-ND had lower (TRT*DRENCH; P &lt; 0.05) WBC than IN-D lambs (1.9 and 2.0 ± 0.042 x 109/L, respectively). A significant (TRT*DRENCH*DAY; P &lt; 0.01) interaction was found on RBC. The CT-D had lower (P &lt; 0.05) RBC on d 7 and greater (P &lt; 0.05) on d 28, 35, 42, and 57 than IN-ND as well as on d 28 than IN-D. Furthermore, CT-ND had greater (P &lt; 0.05) RBC on d 21, 28 and 35 than IN-D and from d 21 to 57 than IN-ND. The IN-D had greater (P &lt; 0.01) RBC from d 35 to 57 than IN-ND. These findings suggest compromised growth in both drenched and non-drenched infected groups. Infection slightly peaked in the infected lambs on d 7 post-inoculation, but drench administration was effective at mitigating overall infection by day 21 and the anemia by day 35.
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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 | 0,003 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 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 ».