How does Conker the Squirrel get the cow to poop enough?

I just got this game off Ebay for N64 and I can't figure out the part where you have to get cow poop for the dung beetle! How many times do you have to do it? Is there more than one cow? Help!How does Conker the Squirrel get the cow to poop enough?
Control the bull to charge at the cow to make her drink the prune juice. Then when she starts crapping ram her again. Repeat this until the bull dies.