Variability in particulate concentrations in a horse training barn over time.

The research investigated varying particulate concentrations in a horse training barn over a span of 30 months. Results demonstrated that horse exposure to these particulates varies due to seasonal changes, feeding methods, and individual horse behavior, with individual horse behavior and feeding methods being significant factors.

Research Purpose and Methodology

• The purpose of this study was to measure and understand the variability in particulate concentrations in a horse training barn. These particulates have previously been linked to causing airway inflammation in horses.
• The researchers wanted to evaluate the difference in variations over time (daily, monthly), differences between horses and the effect of different hay feeding methods.
• This required taking measurements of the area and breathing zone particulate concentrations which were done over a 30-month period in a Thoroughbred training stable.
• The team utilized mixed-model analysis of variance to determine if the time of sampling (month and year) and the daily variance affected the area particulate concentrations.
• Real-time measurements of particulate matter with an aerodynamic diameter of 10 microm or smaller, also known as PM10, were taken to study the effect of the positioning of the barn door.
• P-level was set at less than 0.05 to determine significance of the results.

Key Findings

• Daily variations did not significantly affect average area particulate concentrations, but there was significant variation based on the month and year of sampling.
• We see that daily variations significantly affected the maximum area respirable particulate concentrations in contrast to the average area.
• Open barn doors led to lower PM10 levels, indicating that ventilation reduces particulate concentrations.
• Different feeding methods caused significant variations in particulate exposure: horses fed from hay nets were exposed to significantly higher concentrations of respirable particulates in their breathing zones compared to when they were fed hay on the ground.
• There was significant variability between individual horses in terms of breathing zone concentrations.
• Breathing zone concentrations were significantly higher than area concentrations, and the two measures were not correlated.

Conclusion and Suggestions for Future Research

• Area respirable particulate concentrations, while reflecting seasonal changes, do not accurately predict individual horse exposure. Rather, this research suggests that feeding methods and individual horse behavior play significant roles in shaping exposure to particulates.
• As such, future studies investigating lung health effects on natural exposure in horses should take into account individual behavior and management practices affecting breathing zone exposure.