The horn doesn't matter it's what you do with it. At least 1-2 weeks before you want to move a heard of cattle, show up with a sack full of cattle cubes or some other sweeet feed they love.
Blow the horn over and over, and throw out the feed. Come back the next day at the same time and repeat.
Within a few days, Pavlov takes over and they will follow that horn like it's mamma calling.
It helps to have an extra horn, that way using your normal horn won't confuse their bovine minds.
