Environmental heat and airborne pollen concentration are associated with increased asthma severity in horses.

The research investigates the association between environmental heat and pollen concentration with an increase in asthma severity in horses. The longitudinal study found significant correlations suggesting that a colder environment could reduce the severity of airway obstruction in horses with severe equine asthma.

Objective and Methodology

The main objective was to study the association between environmental temperature, humidity and clinical signs of asthma in horses, particularly during exacerbation periods of the disease.

A retrospective longitudinal study was performed on 14 severe asthmatic horses that were exposed to dusty environments. The horses were evaluated using a previously validated clinical scoring system.

• Data on barn temperature and relative humidity values were gathered and air enthalpy was calculated.
• The researchers used correlation tests to study the relationship between the mean daily clinical scores of horses and environmental variables.
• To compare, lung function parameters were recorded at 4-day intervals during both hot (25°C) and warm (18°C) barn conditions.

Results

The study revealed significant positive correlations between the mean daily clinical score and temperature, and between the mean daily score and air enthalpy. Additionally, maximal daily temperature correlated with airborne pollen concentrations.

• In situations where management of horses was unchanged, increases in barn temperature and enthalpy were associated with increased transpulmonary pressure, pulmonary resistance, and elastance values.
• This suggests that environmental conditions such as temperature and air enthalpy influence the severity of asthma in horses.

Conclusions

Based on the findings, the researchers concluded that by providing a colder environment, the severity of airway obstruction in horses experiencing uncontrolled severe asthma may be reduced. Also, as they found a correlation between environmental heat and pollen concentrations with increased severity, they suggest these factors should be considered in evaluations and when creating a response to therapy in clinical or research settings.