ANSC Feeds Practice Exam

Which hay, harvested in the same field, will have a higher digestibility?

1. Hay harvested in June

2. Hay harvested in July

3. Both will have the same digestibility

4. This cannot be answered without additional data

The correct answer is: Hay harvested in June

The reason why hay harvested in June is likely to have a higher digestibility compared to hay harvested in July stems from the growth stage of the plants at the time of harvesting. Hay that is cut earlier, such as in June, typically comes from plants that are younger and still in the vegetative stage. At this point in their growth, the plants generally contain higher levels of nutrients and a lower concentration of fiber, which tends to make the hay more palatable and easier for animals to digest. As plants mature, which they do as time passes into July, they often undergo changes that can decrease digestibility. The plants develop more lignin in their cell walls and produce more fibrous material, both of which contribute to lower digestibility. Therefore, hay cut in July, coming from fully mature plants, would likely have diminished nutritional value compared to hay harvested in June. This concept is crucial for understanding the nutritional management of herbivores, as selecting the right timing for hay harvest can significantly impact feed quality and animal performance. The choice of harvest time is a key factor in optimizing the digestibility and overall nutritional value of forage crops.