Ingestion of Soil by Grazing Sport Horses.
Authors: Jurjanz Stefan, Collas Claire, Quish Carol, Younge Bridget, Feidt Cyril
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Soil ingestion in grazing horses poses a genuine clinical risk—sand colic and enteritis are well-documented consequences—yet quantitative data on intake rates remain scarce compared to other livestock species. Jurjanz and colleagues studied Irish sport horses across three herbage allowance levels (2, 3, and 4% of body weight daily) using faecal soil marker recovery to measure actual soil consumption, with post-grazing sward heights recorded to assess grazing behaviour. Soil intake increased inversely with herbage availability: horses offered the most restricted pasture (2% allowance) ingested 648 g soil daily and grazed to just 3.1 cm sward height, compared with only 543 g daily at the 4% allowance where residual sward height reached 4.4 cm. This inverse relationship—tighter grazing of depleted pastures driving significantly greater soil consumption—suggests that sward management is a practical lever for reducing gastrointestinal risk in grazing sport horses. For practitioners managing competition horses on pasture, monitoring post-grazing sward height as a management threshold offers a simple, evidence-based approach to withdraw animals before soil ingestion reaches clinically problematic levels, particularly during seasonal feed scarcity or when managing multiple horses on limited grazing.
Read the full abstract on PubMed
Practical Takeaways
- •Monitor sward height during grazing management: allow pasture to reach at least 4+ cm before grazing to reduce soil ingestion and associated colic/enteritis risk
- •Restricted herbage availability forces horses to graze closer to soil; ensure adequate forage allocation (3-4% body weight daily) to minimize grazing pressure on pasture
- •Use sward height as a practical on-farm tool to time horse withdrawal from pasture and protect digestive health, particularly for sport horses prone to sand colic
Key Findings
- •Sport horses grazing at restricted herbage allowance (2% body weight) ingested 4.5% soil in total intake compared to 3.7% at 4% herbage offer
- •Soil ingestion was 624 g/day at 2% herbage offer versus 543 g/day at 4% offer, demonstrating inverse relationship with available forage
- •Post-grazing sward height was significantly lower at 2% offer (3.1 cm) compared to 4% offer (4.4 cm), indicating closer grazing to ground
- •Sward height management is a reliable indicator to determine when to withdraw horses from pasture and reduce gastrointestinal disease risk from soil ingestion