Pulse Brain · Growing Health Evidence Index
Tier 3 — Observational / field trialPeer-reviewed

Threshold levels of artificial infection with Haemonchus contortus impacting lamb physiology and production.

Hempstead MN, Candy PM, Hannaford R, Ross MA, Sutherland IA, Sauermann CW.

Sci Rep · 2025

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Summary

This study investigated the dose-dependent effects of artificial Haemonchus contortus infection on lamb physiology and production performance, seeking to define threshold levels at which welfare and productivity are meaningfully compromised. By using controlled infection doses, the authors aimed to generate evidence supporting more precise decision-making in anthelmintic treatment protocols. The findings are likely relevant to the broader challenge of managing gastrointestinal nematodes under selective treatment strategies, where avoiding unnecessary drug use is a priority.

UK applicability

Haemonchus contortus is an increasing concern in the UK, particularly in southern England and Wales, where warming climates are extending its seasonal prevalence. The threshold data from this study could inform UK targeted selective treatment (TST) frameworks, though differences in breed, climate, and pasture management may require local validation.

Key measures

Packed cell volume (PCV); faecal egg counts (FEC); liveweight gain (kg); haematological parameters; worm burden at necropsy

Outcomes reported

The study examined the physiological and production responses of lambs artificially infected with varying dose levels of the barber's pole worm (Haemonchus contortus), likely measuring haematological indicators, liveweight gain, and parasite burden. It aimed to identify threshold infection levels at which measurable negative impacts on lamb health and productivity become apparent.

Theme
Farming systems, soils & land use
Subject
Livestock health & parasitology
Study type
Research
Study design
Controlled animal experiment
Source type
Peer-reviewed study
Status
Published
Geography
New Zealand
System type
Pasture-based sheep
DOI
10.1038/s41598-025-04327-3
Catalogue ID
NRmo3f02hq-08a

Topic tags

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