hi when i am training collies to cattle we do it on a long rope allow them a lose contact and when you call there name pull gently on the rope do this over and over untill the dog comes back dont let the dog of the rope untill this 100% you can give them a small bit of meat or treat when they come right up to you. you can also crouch down while recaling as when you do let them off they can see you but not hear you they come back its important to have the recall 100% before you do anthing else as in the dogs mind you have to be top of the pack to gain is respect i have retraind lots of dog