Maximum permissible load for Kiso horses trotting over a short, straight course.

The research investigates the maximum weight that Kiso horses can carry at a trot. The findings suggest that Kiso horses can bear a load of less than 120 kilograms, accounting for 31% of their body weight.

Research Objectives and Methodology

• The primary aim of this study was to ascertain the maximum permissible load a Kiso horse can bear while trotting. Kiso horses, originating from Japan, were selected due to their average size, typical of many breeds around the world.
• For the research, 10 Kiso horses, each with a height of 128cm at the withers, were chosen. To understand load effects, their riders were fitted with a 70mm marker on their chest.
• The horses and riders were recorded by two digital DVD cameras as they trotted over a short, straight course. In total, each horse trotted eight times– two rounds with a 70kg load, followed by six trial rounds with randomly allocated weights ranging from 80 to 130kg.

Gait Analysis and Data Interpretation

• Data obtained from the marker’s three-dimensional movement was scrutinized using a motion capture system. The vertical displacement of the marker was subjected to spectrum analysis using the maximum entropy method and the autocorrelation coefficient was determined.
• Two primary features were identified in the data, termed as symmetry and regularity. They describe the rhythmic, balanced movement of the horse. Their cumulative sum was referred to as stability– a unit to measure the horse’s comfortable or smooth gait while carrying the load.
• The analysis reveals a notable decline in regularity and stability when the load was increased to 120kg. Regularity fell from 0.61 (at a 70kg load) to 0.54 and stability decreased from 1.42 to 1.31.

Conclusion of the Study

• Based on the observed decrease in regularity and stability, the researchers asserted that the maximum permissible load for a trotting Kiso horse should be less than 120kg. This represents about 31% of its body weight.
• Exceeding this load could disrupt the horse’s ability to maintain a rhythmic, balanced trot, potentially leading to discomfort or injury.