PSX-27 Growth performance and immune response dynamics in weaned lambs with subclinical <i>Haemonchus contortus</i> parasite infection
Bibliographic record
Abstract
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 < 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 < 0.05) WBC than IN-D lambs (1.9 and 2.0 ± 0.042 x 109/L, respectively). A significant (TRT*DRENCH*DAY; P < 0.01) interaction was found on RBC. The CT-D had lower (P < 0.05) RBC on d 7 and greater (P < 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 < 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 < 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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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".