I have never seen deer spook as cows approached, but I have not witnessed deer mingling within a group of cattle. I have seen deer spook like crazy when feral hogs came in. However it could be that the cows have found the corn and are out muscling the deer for the grain. I am just not sure.

As far as coyotes. I have seen deer bust out like they were shot at a cannon at the sight of a coyote and I have seen deer stand and just keep an eye on a coyote as walked by within 20-30 yards. And then gp right back to feeding when the coyote left. Bottom line I don't think that it it either the coyotes or cows in the area that have caused the deer to vacate the corn piles.

I think maybe the deer have moved on to a more preferred food, such as maybe fresh dropping acorns or some nearby fields ag being harvested (soy beans , corn) ??? Not sure if the acorns are hitting the ground up that way or not. Some of the white oaks and chestnut oaks in the woods behind my house have started dropping.

You might try scoputing gor acorns and see if there are deer droppings around the oaks. If that is the case, you may have your answer why they have stopped passing by your camera location.