Determining energy requirements and comparing these to the energy content of the diet is important when managing horses that are either under- or over-weight. | Photo: Alexandra Beckstett/The Horse

Q: I’ve read articles that talk about the horse’s energy requirement in terms of Mcals of digestible energy. What is digestible energy and what is Mcal?

A: In the United States, we measure daily energy requirements for both humans and animals in terms of calories. One calorie is actually a heat measure and is the energy it takes to heat 1 gram of water 1 degree Celsius. Many areas of the world use joules as their measure of energy and 1 calorie is equal to 4.1868 joules.

It’s important to note whether we’re talking calorie with a lowercase c or Calorie with an upper case C—the the latter is actually the measure of energy needed to raise the temperature of 1 kilogram of water 1 degree Celcius. Therefore 1 Calorie is actually 1,000 calories, often referred to as one kcal where k stands for 1,000