Testing optimal methods to compare horse postures using geometric morphometrics

Area of Science:

• Animal behavior
• Welfare science
• Biomechanical analysis

Background:

• Assessing animal welfare requires reliable tools for quantifying behavior, particularly posture.
• Existing methods for posture analysis are often subjective or limited in scope.
• Geometric morphometrics (GM) has shown promise for analyzing animal body outlines and comparing populations.

Purpose of the Study:

• To optimize existing geometric morphometrics (GM) methods for horse posture analysis.
• To introduce novel techniques like sliding semilandmarks (SSL) and focus on specific body regions.
• To evaluate if the optimized GM method can better differentiate horse populations.

Main Methods:

• Photographs of 85 horses from 11 riding schools were analyzed.
• An optimized GM method incorporating sliding semilandmarks (SSL) and excluding neck movement was developed.
• The new method focused analysis on specific parts of the horse's upper body line (dorsum).

Main Results:

• The optimized GM method, using SSL and excluding neck movement, demonstrated superior discrimination between horse populations compared to previous GM methods.
• Analysis of the dorsum proved effective in differentiating populations.
• The refined methodology showed improved ability to distinguish groups based on housing and working conditions.

Conclusions:

• The optimized geometric morphometrics (GM) method with sliding semilandmarks (SSL) offers enhanced reliability for quantifying animal posture.
• This improved methodology holds potential as an indicator of horse welfare state.
• Further validation in other species is recommended to establish broader applicability.