A rancher needs a bull to service his cows but needs to borrow the money for it from the bank. The banker, who lends the money, comes by a week later to see how his investment is doing. The farmer complains that the bull just eats grass and won't even look at the cows. The banker suggests that a veterinarian have a look at the bull.
The next week the banker returns to see if the vet helped. The farmer looks very pleased: "The bull has serviced all my cows, broke through the fence and serviced all my neighbor's cows."
"Wow," says the banker, "what did the vet do?" "Just gave him some pills," replies the farmer. "What kind of pills?" asks the banker.
"I don't know," says the farmer, "but they sort of taste like vanilla."