KEY Assignment Topic # 3042 Essay The answer should contain three key ideas: Excess protein is used to manufacture energy once the amount needed for growth is achieved. It is not harmful to the animal, but is more expensive than other energy resources such as carbohydrates. The main difference between ruminants and monogastric amino acid absorption is how the acid are received. The bacteria in a ruminants digestive tract make the amino acids needed, but need the Nitrogen from the feed to do so. Monogastric absorb the amino acids from feed. It is more important for a young animal to have enough protein because it is used for growth and building new tissue. A mature animals protein needs are much less than that of a young animal.