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Animals : an open access journal from MDPI2025; 15(18); 2688; doi: 10.3390/ani15182688

Sensory Assessment of Hay Samples: Abnormal Odor Predicts Increased Dust Levels and Impurities Suggest Microbiological Contamination.

Abstract: Hay quality is a key factor in equine respiratory health, with microbiological contaminants in inhaled organic dust posing significant risks. Sensory assessment has been used to evaluate hay hygiene, but its value to identify deficiencies remains unclear. This study aimed to explore the potential of sensory assessment to predict both particulate matter (PM) dust concentrations and microbiological contamination. Fifty hay samples were collected from horse owners and evaluated using a structured sensory examination, microbiological analyses, and dust concentration measurements obtained with the Hay-Shaker device and a DustTrak DRX 8534. Sensory examination rated only 28% of samples as adequate, with 52% showing minor and 20% major deficiencies. Microbiological analysis found that 46% of samples met acceptable standards. Regression analysis showed that abnormal musty odor was the strongest predictor of increased dust concentrations, including the respirable fraction (PM4, <4 µm), while visible impurities were associated with microbial contamination. These findings suggest that sensory attributes such as odor and impurity are valuable indicators of hay hygiene. Structured protocols for sensory examination may offer a simple and cost-effective tool for assessing hay quality in equine environments.
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Publication Date: 2025-09-14 PubMed ID: 41007933PubMed Central: PMC12466340DOI: 10.3390/ani15182688Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Plain Language Overview

  • This study investigated how well sensory assessment (like smelling or visually inspecting hay) can predict dust levels and microbiological contamination in hay, which affects horse respiratory health.
  • It found that abnormal odors in hay signal higher dust levels, while visible impurities suggest the presence of microbes, indicating that simple sensory checks could help identify poor hay quality.

Detailed Explanation of the Research Paper

Background and Importance

  • Hay quality significantly impacts equine respiratory health because poor-quality hay can contain inhalable organic dust laden with microbiological contaminants, which pose health risks.
  • Traditional sensory assessment (smell, appearance, touch) has been used to evaluate hay hygiene but needed further validation as a predictive tool for dust and microbial contamination.

Study Objective

  • The primary aim was to explore whether sensory assessment can predict particulate matter dust concentrations and microbiological contamination in hay.
  • The goal was to determine if odors and visible impurities detected through sensory checks correlate with objective measurements of dust and microbes.

Methods

  • Collected 50 hay samples from various horse owners to represent typical equine environments.
  • Conducted a structured sensory examination that assessed:
    • Odor characteristics (e.g., musty or abnormal smells)
    • Visual appearance, including detection of impurities
    • Other sensory parameters potentially relating to quality
  • Performed microbiological analyses to quantify contamination levels against accepted standards.
  • Measured dust concentrations using:
    • Hay-Shaker device (for shaking out dust from hay)
    • DustTrak DRX 8534 (for detailed particulate matter sizing and concentration, including respirable fraction PM4, particles under 4 micrometers)

Results

  • Sensory assessment findings:
    • Only 28% of samples rated as adequate hay quality
    • 52% showed minor deficiencies
    • 20% exhibited major deficiencies based on sensory criteria
  • Microbiological results:
    • 46% of samples met acceptable microbial contamination standards
    • Remaining samples showed contamination concerns
  • Regression analysis indicated:
    • Abnormal musty odor was the strongest predictor for increased dust concentrations, including the respirable fraction PM4, which is critical since smaller particles can reach deep into the lungs.
    • Visible impurities in hay were strongly associated with higher microbial contamination.

Interpretation and Implications

  • Abnormal odor serves as a useful, easily detected sensory marker for higher dust exposure risk in hay.
  • Visible impurities can be a practical indicator for microbiological contamination, which is harder to assess without lab testing.
  • Structured sensory protocols could be developed and standardized to provide horse owners and caretakers with a simple, cost-effective way to assess hay hygiene on-site, potentially reducing respiratory risks.
  • The study supports using sensory assessment as a frontline screening method, helping prioritize samples for detailed lab analysis when needed.

Limitations and Future Directions

  • The study included only 50 samples, so further work with larger sample sizes across diverse regions would help validate findings.
  • While sensory evaluation is useful, it cannot fully replace precise microbiological and dust measurements but functions best as a complementary tool.
  • Future research could focus on refining sensory protocols and incorporating training for horse owners or stable managers for better hay management.

Cite This Article

APA
Bouverat VMA, Pradervand N, Wichert BA, Greim E, Dolf GJ, Gerber V. (2025). Sensory Assessment of Hay Samples: Abnormal Odor Predicts Increased Dust Levels and Impurities Suggest Microbiological Contamination. Animals (Basel), 15(18), 2688. https://doi.org/10.3390/ani15182688

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 15
Issue: 18
PII: 2688

Researcher Affiliations

Bouverat, Virginie Marie Angèle
  • Swiss Institute of Equine Medicine (ISME), Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Bern, 3012 Bern, Switzerland.
Pradervand, Nicolas
  • Feed Biology Laboratory, Division of Methods Development and Analytics, Agroscope, 1725 Posieux, Switzerland.
Wichert, Brigitta Annette
  • Institute of Animal Nutrition and Dietetics, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.
Greim, Eloïse
  • Swiss Institute of Equine Medicine (ISME), Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Bern, 3012 Bern, Switzerland.
Dolf, Gaudenz Jürg
  • Swiss Institute of Equine Medicine (ISME), Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Bern, 3012 Bern, Switzerland.
Gerber, Vinzenz
  • Swiss Institute of Equine Medicine (ISME), Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Bern, 3012 Bern, Switzerland.

Grant Funding

  • 33-890 / Internal Research Fund of the Swiss Institute Equne Medicine, Bern, Switzerland
  • Foundation based in Geneva, Swiizerland wishing to remain anonymous

Conflict of Interest Statement

The authors declare no conflicts of interest.

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