Higher NDF content in forages generally leads to what effect on intake and energy availability?

• A. Increases intake
• B. Decreases intake and energy availability
• C. Has no effect
• D. Only affects palatability

Answer: (B)

The main concept is that forage fiber levels control how much an animal can eat and how much energy they get from that feed. Neutral detergent fiber reflects the structural parts of the plant; more of it means more rumen fill and slower digestion. When the forage is high in NDF, the rumen fills up more quickly and stays fuller longer, so the animal reaches its comfortable intake level sooner and eats less. Since total energy intake tracks with how much dry matter is consumed, higher NDF also reduces energy availability. Additionally, high-fiber feeds are less energy-dense and less fermentable than forages high in starch or sugars, so the energy per unit of feed is lower even before considering intake. So higher NDF generally lowers both intake and the usable energy from the diet.