Preliminary observations on inhalation and intradermal challenges of horses with oil seed rape.

The study explores how exposure to oil seed rape, either through physical contact or inhalation, affects horses with chronic obstructive pulmonary disease (COPD). The result reveals that this interaction has no significant impact on horses that are either healthy or symptom-free COPD sufferers but can worsen the condition in COPD horses showing symptoms.

Research Objective

• The aim of this research was to understand how exposure to oil seed rape might affect horses with or without chronic obstructive pulmonary disease – a common pulmonary condition in horses – by testing different types of challenges including direct exposure in a field, inhalation of fresh pollen, and exposure to a commercial extract of the pollen.

Methodology

• Both healthy horses and horses with COPD were exposed to flowering Brassica campestris in a field for six days.
• They were also tested through an inhalation challenge, where they inhaled freshly collected Brassica napus pollen, and a commercial extract of B napus pollen.
• After these exposures, the horses underwent clinical and bronchoscopic examinations to assess if there were any changes in their pulmonary health.

Results

• The challenges did not cause any detectable change in the respiratory health of healthy horses, or those with COPD but showing no symptoms. This was measured through evaluations like pulmonary mechanics, arterial blood gas tensions, arterial pH or the cytology of bronchoalveolar lavage fluid.
• For some horses with symptomatic COPD, the exposure to fresh B. napus pollen and a commercial pollen extract caused worsening of their pulmonary disease. This could be because of non-specific toxicity or non-specific bronchial hyperresponsiveness caused by the challenges.
• All horses were tested for hypersensitivity to the commercial B napus pollen extract using an intradermal testing method. The results showed that none of the horses were hypersensitive to this substance.

Conclusion

• This study concluded that exposing horses to oil seed rape doesn’t have a detectable negative impact on the respiratory health of healthy horses, or horses with asymptomatic COPD. However, horses with symptomatic COPD could experience exacerbated respiratory symptoms possibly due to non-specific toxicity or bronchial hyperresponsiveness. None of the tested horses showed hypersensitivity to the commercial extract of B. napus pollen.