After harvesting the ears of the corn, I believe there is nothing left in the crop. All the major protien and other nutrients are sent into the cob and other nutrients in the stem and leaves are too little to be usefull.
It will result in very poor silage. Another point is if the crop is too dry then silage will get overheated resulting in spoilage. The dry matter of the maize crop at the time of silaging should be 60-70%. This will result in silage with 40% dry matter.
Nikhil