Start feeding range cubes from a five gallon bucket. Get them used to the noise is makes when you rattle the bucket. You can dump them on the ground or in a dish. Before long the cow will go where ever the bucket goes... Need them in a trailer? Once they are "feed" trained, you put the dish at the front of the trailer and close the door when they walk in. You might have to start at the back and work your way forward. Start this process a week or so before you need to load them.