Tag: Gross energy

Gross energy, also known as the heat of combustion, is the total chemical energy released when a feedstuff is completely burned. It is the foundational measurement in feed energy evaluation for livestock and other animals, providing a starting point for assessing nutritional value. Understanding how this measurement is performed is crucial for animal nutritionists and producers.

According to the National Research Council, dietary energy is the most important component of an animal's diet after water. Understanding the difference between digestible energy (DE) and metabolizable energy (ME) is fundamental to accurately assessing feed quality and ensuring proper nutrition for livestock and pets.

The energy an animal derives from its food is a critical metric in nutrition, and approximately 19% of a ruminant's digestible energy may be lost before it can be fully metabolized. Digestible energy (DE) quantifies the portion of an animal's dietary energy that is actually absorbed, excluding the energy lost through feces.

According to nutritional studies, humans and animals lose up to 10-15% of total food energy through feces and urine. This unabsorbed portion is why the total energy content of food, measured through combustion, is not the same as the energy an organism can actually use, a value known as metabolizable energy.

Over 65% of the cost of raising livestock is attributed to feed, making energy the most expensive component in an animal's diet. This is why understanding exactly how we measure the amount of energy in feed is crucial for formulating cost-effective rations and optimizing animal health and productivity.

According to the U.S. Government Accountability Office, net energy is the usable energy from a resource after subtracting the energy expended to locate, extract, refine, and deliver it. A positive net energy indicates a surplus of usable power, while a negative value signals a deficit.

In animal nutrition, over 40% of the gross energy in some fibrous feeds is lost in feces alone, highlighting a critical distinction. Understanding this key difference between net energy and gross energy is essential for accurately evaluating a food source's true nutritional value for an organism.

The human body absorbs only about 95% or less of the total energy contained within the food we consume, meaning the listed calories on a nutrition label are not the full story. The net energy of a food represents the true, usable energy remaining after the energy losses that occur during digestion and metabolism are accounted for.

According to Oregon State University, energy is a concept, not a nutrient, but is a crucial property of nutrients that can be measured to assess feed quality. Understanding what is total digestible energy (TDN) is essential for livestock owners and nutritionists to accurately formulate diets that meet an animal's energy requirements for maintenance, growth, and reproduction.

In animal nutrition, digestible energy is the difference between the gross energy intake from a feed and the energy lost through feces. A feed’s total chemical energy is not fully available to the animal, making this measurement a crucial metric for diet formulation and assessing nutritional value.