Question

Does hay lose its nutritional value while in storage?

Answer

Hay begins to lose its nutritional value at the time of cutting and continues to lose nutritional value while in storage. The nutrients most affected by harvesting and storage are vitamins, with the protein and mineral content of hay being quite stable.

All green parts of growing plants are rich in carotene and, therefore, have a high vitamin A value. In fact, the degree of green color in a plant is a good index of vitamin content. Approximately 50% of the vitamin A may be lost from hay during the first 24 hours of the curing process. If the hay is subjected to rain or other weather damage, the vitamin losses are greater. The losses of vitamin content continue during storage with the rate of destruction determined by temperature, exposure to air and sunlight, and length of storage time.

Under average conditions where hay is stored in a barn, vitamin content of hay can be expected to decrease by approximately 7% per month. If hay is left outside without cover, the vitamin losses will be greater. Again, the color of hay is the best non-laboratory means of determining vitamin content. The greener the hay, the higher the vitamin level.