I came across this article “Drough-Damaged Corn Silage Considerations” and I wanted to highlight a few points from the article:
Allow the corn to stay in the field as long as possible because, if rains come, they may bring more stalk and leaf growth, and more tonnage at harvest time.
The crude protein content of drought silage will likely be higher (11 percent) than that found in normal corn silage (8 percent) on a dry basis. In normal corn silage much of the protein is found in the grain. In drought-damaged corn more of the protein is found in the plant. This protein is more soluble in the rumen than protein found in corn grain. Therefore, the feeding of supplements containing large quantities of urea (NPN) may not work as well for animal performance than when a plant protein is fed.
A “quick and dirty” method of estimating time to harvest is to squeeze a stalk in your hand for 30 seconds. If moisture drips from the stalk after squeezing, it is too wet for optimum ensiling. The crop needs to remain in the field a little longer or should be layed down in the field for 12 to 24 hours. If the stalk remains compacted after squeezing, the moisture level is acceptable for direct cutting. If the stalk bounds back after squeezing, the crop may be drier than it should be and water will need to be added while putting the corn in a silo or pile. The moisture level may drop rapidly as the plant begins to die.
Watch this video if you want a a deeper understanding of this topic. The video looks at the nitrate and protein values and presents this information with recommendations.
Picture via lady_lbrty