What is the definition of total digestible nutrients (TDN) and how is the amount computed?
A) TDN is the total amount of nutrients available for digestion by animals, computed by summing the percentages of crude protein, crude fat, crude fiber, nitrogen-free extract, and subtracting the percentage of ash.
B) TDN represents the total daily nutrient intake of animals, computed by analyzing the proportions of essential minerals, vitamins, and proteins in their diet.
C) TDN refers to the total dietary intake of animals, calculated by measuring the dry matter content of their feed and subtracting the moisture content.
D) TDN is the total amount of nutrients absorbed by animals during digestion, computed by assessing the percentage of carbohydrates, proteins, and fats in their diet.