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 experimental study established dose-response relationships between Haemonchus contortus infection intensity and lamb physiological and productive responses. By artificially infecting lambs with defined parasite doses, the authors identified critical threshold levels where gastrointestinal nematode infection begins to significantly impact growth performance and systemic health markers. The findings inform evidence-based parasite management thresholds for sheep production systems.

UK applicability

Highly applicable to UK sheep farming, where Haemonchus contortus is an endemic gastrointestinal parasite of significant economic importance. The threshold data directly inform UK best practice guidance on when anthelmintic treatment becomes economically or welfare-justified in grazing flocks.

Key measures

Parasite burden levels, lamb weight gain, feed intake, blood parameters (likely haemoglobin, packed cell volume, plasma proteins), and possibly faecal egg count

Outcomes reported

The study experimentally infected lambs with controlled doses of Haemonchus contortus and measured effects on physiological markers and production metrics across different infection intensities. It identified threshold infection levels at which measurable impacts on lamb health and performance become evident.

Theme
Farming systems, soils & land use
Subject
Livestock health & parasite management
Study type
Research
Study design
Field trial
Source type
Peer-reviewed study
Status
Published
Geography
UK
System type
Pasture-based sheep
DOI
10.1038/s41598-025-04327-3
Catalogue ID
NRmo3d4gae-0a8

Topic tags

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