ANSC Feeds Practice Exam

As the TDN:CP ratio of a forage increases, what happens to forage intake by beef cows?

1. Increases

2. Decreases

3. Remains the same

4. Varies widely

The correct answer is: Decreases

As the Total Digestible Nutrients (TDN) to Crude Protein (CP) ratio of a forage increases, beef cows tend to experience a decrease in forage intake. This relationship is primarily influenced by the nutritional balance that cows seek to achieve for optimal health and productivity. Forage with a higher TDN:CP ratio indicates that the forage is providing more energy (digestible nutrients) relative to its protein content. When the energy content exceeds protein requirements, it can lead to a situation where beef cows may not feel compelled to consume as much forage to meet their energy needs since the energy is readily available with less protein. In contrast, forages with a lower TDN:CP ratio generally require cows to consume more to meet both their energy and protein needs, thus increasing overall forage intake. Additionally, the quality of the forage plays a significant role: if the protein is too low in proportion to the energy available, cows may limit their intake to avoid an imbalance in their diet, which is essential for their physiological functions and productivity. Understanding this dynamic is crucial for managing beef cattle nutrition effectively, ensuring that forages are balanced in their nutrient profiles to maximize intake and overall health.