Clinton: Don't look a gift...cow in the mouth?

From today's World Section on CNN:

NAIROBI, Kenya (AP) -- A Kenyan says he offered Bill Clinton 40 goats and 20 cows for his daughter's hand in marriage five years ago -- and is still waiting for an answer.

I can understand the 40 goats, but why would he want 20 more cows?

l8r