Coprological and Molecular Analyses of Ruminant Farms in Québec, Canada, Show a Variable Efficacy of Ivermectin Against Gastro-Intestinal Nematodes
Bibliographic record
Abstract
Gastro-intestinal nematodes (GINs) are still of great concern in grazing ruminants, such as camelids, ovines and caprines, affecting animal health and productivity. This is mainly due to the development of anthelmintic resistance (AR) to the compounds used long term, without much evaluation on their efficacy, including ivermectin (IVM), the most used anthelmintic drug in livestock. The aims of this study were to determine the efficacy of IVM and identify which GIN species are affecting different ruminant farms in Quebec (QC), Canada. Firstly, we collected fecal samples from six farms with different ruminant species (camelids, goats and sheep) before and after IVM treatment when applicable, analyzing them by Fecal Egg Count (FEC) and further assessments on IVM efficacy through the Fecal Egg Count Reduction Test (FECRT). In addition, molecular analyses were conducted using PCR, targeting the ITS-2 and COX-1 genes to identify GIN species. FECRT was applied only for three farms, showing that variable results with optimal efficacy (ranging from 95.5–100%) were obtained in only one farm, whereas on the other two farms, FECRT exhibited reduced efficacy, suggesting the development of IVM resistance. Among the GIN species found, Haemonchus contortus and Trichostrongylus vitrinus were identified in most of the farms, being present in sheep, goat, llama and alpaca farms, whereas Teladorsagia circumcincta was identified only in sheep and llama samples from four farms but not in alpaca samples. Trichostrongylus axei and Chabertia ovina were present in two farms (sheep and sheep and llamas). Oesophagostomum venulosum was detected in one sheep and one alpaca farm. Only one sheep farm was positive for Trichostrongylus colubriformis and Cooperia curticei. Also, Nematodirus spp. and Trichuris spp. were found in four farms, including sheep and camelids. In addition, three other species were found in camelids, including Camelostrongylus mentulatus (only in the llama samples), whereas Lamanema chavezi and Marshallagia marshalli were identified in one alpaca farm. Therefore, our work reports evidence of an uneven efficacy of IVM against GINs from ruminant farms, including the most likely emergence of IVM resistance. The diversity of GIN species found in ruminant farms in QC along with the inconsistent IVM efficacy are helpful information for veterinarians and animal producers in setting an optimal parasite management programs, including the proper use of IVM and alternative anthelmintic drugs to control these pathogens in grazing livestock.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".