Reduction of the olfactory cognitive ability in horses during preslaughter: stress-related hormones evaluation.

The research article focuses on how the application of a mentholated ointment to horses’ nostrils before they are slaughtered can potentially reduce their stress response by blocking their perception of danger signals.

Objective of the Study

• The main aim of this study was to determine the effect of a mentholated ointment application to horse nostrils on their stress response during pre-slaughter handling. They attempted to achieve this by analyzing the horses’ plasma levels for cortisol, beta-endorphin, epinephrine, and norepinephrine before and after stunning.

Methodology

• The researchers selected twenty draught-type horses and divided them into two equal groups: a control group and a treated group.
• In the treated group, the horses had a mentholated ointment applied to their nostrils around 45 minutes prior to slaughter, following an initial blood sample taken in a lairage. It was hypothesized that this technique would influence the perceived threatening odour signals that can be present during slaughter.

Results and Findings

• The treatment did not have any significant effects on the plasma concentrations of cortisol or beta-endorphin in the horses.
• However, noteworthy reductions were observed in the concentrations of epinephrine and norepinephrine in the post-stun plasma samples of the treated group.
• This drop in epinephrine and norepinephrine levels implies that the horses’ adrenergic (physiological) response to the slaughter environment was significantly reduced, suggesting a decrease in their overall stress response.

Implications

• The study suggests that applying a mentholated ointment to the nostrils of horses pre-slaughter has the potential to reduce their stress response, likely mitigating perceived threats and making the process more humane.
• This could emerge as a simple and feasible method to improve the animal welfare during preslaughter procedures, potentially influencing industry practices.