I am not a regular user of corn silage. However I did buy two cows from a farm that had them in a pen with some steers and eating the same silage as the steers.  These cows were what I would call "greasy" fat when I bought them, presumably from the corn silage.

After a couple months of grazing and then into winter on hay it was like their whole body type changed.

Based on this I would be extremely careful about feeding bred cows much corn silage.  Perhaps mixed in with a lot of hay etc might be ok but I would be afraid of some super-sized calves and calving problems if they were fed too much silage. jmho.

Jim at Dawn