Cash Cow?

TV has a lot about mysteries on it. A couple of mysteries I have thought about are the Chupacabra and Cattle mutilations. Then one night it occurred to me. I have always thought the only animal to take blood out of a creature and leave the body behind is man, ditto for mutilating. Of course these mystery shows liked to posit that it was coming from aliens. The Chupacabra being an escaped pet of aliens who have visited Earth. The cow mutilations come from the aliens themselves. But I wondered, why would aliens leave a body they could just as easily take with them? To make a long story short, I looked at other animal stories. Stories of poachers. So who leaves the body of an animal to rot? Poachers. Think of the African elephant and Siberian tiger whose remains are found all over their habitat. And why are they poached? Medicine. Or for nickknacks made of ivory or rhinoceros horn. What is taken from the cows is their sex organs. So maybe there's a market for cow sex organs somewhere? Why would a poacher just have a herd of cows when they could steal some for less? And for the animals in Latin-America? Blood is drained. So maybe there's a need for blood in some market in the world? Just a thought. But I can't bring myself to believe that an alien would come millions of miles to Earth just to steal and cow's uterus.