Which factor contributes to a pony's ideal body condition?

The amount of work done significantly contributes to a pony's ideal body condition because it influences the pony's energy requirements and overall fitness level. A pony that is more active and participates in regular work or exercise will require a balanced diet to maintain its energy levels, which helps in achieving and sustaining an optimal body weight and condition. Without adequate work, a pony may not burn off excess calories, potentially leading to overweight issues.

In contrast, while breed type can provide a guideline for expected body conformation, it does not directly dictate a pony's ideal body condition in conjunction with its lifestyle. The availability of pasture also plays a role, but it is more about the quality and quantity of forage rather than a direct factor contributing to body condition. Lastly, the type of equipment used is related to performance and comfort during work, but it does not affect the pony's body condition directly. Thus, the amount of work done stands out as the primary factor influencing both the energy expenditure and overall health of the pony.