Hay is air dried plant material stored to be fed to livestock during dry season. Hay can either be grasses, legumes, fodder or crop residues. The age of cutting determines the quality of hay. Young plants have high protein content but low energy content. The best time to cut grasses is at the time of inflorescence. If cutting is delayed the quality of hay will be poorer.
The crop is cut and left in the field to dry up for baling at a later date. Nutrient losses are caused by respiration which can go up to 10% therefore drying should be as fast as possible. Other losses are due to:
- Bleaching – brought about by exposure to direct sunlight.
- Leaching – this is serious during rainy seasons. Soluble nutrients especially carbohydrates are leached away
- Machinery – wrongly set balers leave a lot of plant material in the field. Collecting and loading bales results in loss because of shattering. This can be reduced if bales are handled carefully.
The quality of hay will depend on the plant species and the period the hay is baled. High quality hay has 25 – 30% fibre content and 12 – 18% protein content. The dry matter (DM) yield increases with the age of the plant material but quality decreases with increasing age.
A reasonable balance between quality and quantity can be achieved by cutting the crop when it has produced a good yield of DM but before quality has declined. For grasses the best time to cut for hay is during the heading stage and for legumes at 15% flowering. And for a mixture of grasses and legumes cutting is best at booting stage of grass.