I think it started when I saved/loaded my world but cows seem to have just stopped eating and are just frozen in place. It happens as soon as I milked them and reloading the save doesn't fix it. It really needs fixing - more annoying than milk storages getting full.
swi had a similar problem, maybe after a load. i had to go and pick them all up and put them down as they wouldn't eat grass when standing ontop of it and that fixed it. they only start eating once discovered so maybe on a load you have to discover them again. i have since reloaded and not found the problem. also anyway to get more seeds out of trees and apples out of apple trees??