Step 1: Understanding the Concept:
Hay is a preserved forage made by drying green herbage to a low-moisture state, which inhibits cellular respiration, mold growth, and fermentation during storage.
Step 3: Detailed Explanation:
Freshly harvested green forage has a high moisture content of around 70--80% (translating to a dry matter of 20--30%).
To prevent microbial decay, spoilage, heating, and spontaneous combustion during storage, moisture must be reduced below 15%.
This requires curing the herbage until the final dry matter content reaches approximately 85% to 88% (specifically matching the 86--88% range).
Step 4: Final Answer
Therefore, hay is cured to achieve a dry matter content of 86-88%.