Feed Intake Parameters of Horses Fed Soaked or Steamed Hay and Hygienic Quality of Hay Stored following Treatment.
Authors: Glatter Maren, Bochnia Mandy, Wensch-Dorendorf Monika, Greef Jörg Michael, Zeyner Annette
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Horses with equine asthma require low-dust forage, but little is known about how soaking and steaming—the two most common hay treatment methods—affect microbial safety during storage or alter the horse's feeding behaviour. Researchers treated meadow hay by soaking (15 minutes at 10–15°C) or steaming (60 minutes at 100°C), then tracked microbial contamination (bacteria, moulds, yeasts) before and after storage at two temperatures for up to 24 hours, whilst simultaneously measuring chewing activity and intake rates in six horses fed each hay type. Steaming proved markedly superior for microbial control, eliminating moulds entirely and reducing yeasts to near-undetectable levels, whereas soaked hay showed rapid microbial proliferation during storage—particularly bacteria, moulds, and yeasts—making it unsuitable for longer-term stockpiling. Both treated hays were consumed more slowly than native hay in the first 60 minutes (soaked and steamed at 21.5 and 19.5 g dry matter per minute respectively, compared to untreated), with steamed hay eliciting substantially more intense mastication (3537 chewing cycles per kilogram dry matter versus 2521 for soaked and 2622 for native hay). For respiratory-compromised horses, steaming offers a more reliable hygiene profile and better palatability, whilst soaking demands immediate feeding to prevent microbial rebound and may be rejected by some horses, making it the less practical choice for routine asthma management.
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Practical Takeaways
- •For horses with equine asthma, steamed hay is the preferred treatment method over soaking due to superior dust reduction and microbial control that persists through storage
- •If soaking is used, feed treated hay immediately—storing soaked hay even at cool temperatures rapidly increases mold, yeast, and bacterial contamination within 6-24 hours
- •Expect steamed hay to be eaten more slowly with increased chewing activity, which may improve digestion efficiency and prolong feeding time for enrichment
Key Findings
- •Steaming reduced mold to 0 CFU/g compared to 50 CFU/g in soaked hay, and reduced yeasts to 0-90 CFU/g versus 102 CFU/g in native hay
- •Soaked hay storage at 10-25°C for 6-24 hours significantly elevated bacterial, mold, and yeast counts, indicating instability
- •Steamed hay was consumed 19.5 g DM/min in the first 60 minutes versus 21.5 g DM/min for soaked hay, and required 3537 chewing cycles/kg DM versus 2622 for native hay
- •Steaming provides superior hygienic quality for asthmatic horses, while soaked hay is unsuitable for storage due to microbial proliferation