Equine energetics. II. Energy expenditure in horses during submaximal exercise.

The research paper examines the amount of energy expended by horses during submaximal exercise, considering factors such as their speed and whether or not a rider was present.

Objective of the Study

The purpose of the research was to evaluate the energy expenditure in horses during submaximal (moderate intensity) exercise. The goal here was to evaluate the energy needed by the animal to perform this level of exercise and understand how that energy requirement changes under different conditions, such as varying speeds or when carrying a rider.

Method and Experimentation

• This study involved four geldings (neutered male horses) of variable weights, ranging from 433 to 520 kg.
• The energy expenditure was measured using a mobile open-circuit indirect respiration calorimeter, a device that measures how much oxygen a body is consuming and how much carbon dioxide it is producing. This helps in calculating metabolic rate or energy expenditure.
• A total of 304 five-minute measurements were taken, considering both situations where the horses were with and without riders.

Findings and Results

• The research found that the energy expended by the horses incremented exponentially with speed. Thus, faster speeds resulted in a significantly higher energy expenditure.
• The energy expended also depended on the body weight of the horse or the combined weight of the horse plus rider and tack, meaning the burden or load the horse carried also affected its energy use.
• An equation (Y = e3.02 + .0065X) was formulated to best describe the total energy expended by the horses when walking, trotting, and cantering. In this equation, ‘Y’ represents the energy expended (measured in calories expended per kilogram of weight per minute), and ‘X’ is the speed of the horse (meters per minute).
• The Digestible Energy (DE), i.e., the portion of dietary energy that is absorbed by the body and available for metabolism and bodily functions above maintenance level, was calculated using a specific formula.

Significance of the Research

• This research provides valuable insights into the energy requirements of horses when engaged in submaximal exercise. This knowledge can influence decisions and practices surrounding horse training, diet, and care.
• Understanding the correlation between speed, load, and energy expenditure can help in making performance-optimizing decisions during races and other competitive events.
• The research could have broader implications for animal energetics in general, which could influence other areas of veterinary science, animal husbandry, or wildlife conservation.