Cow Mutilations in montana

I am stationed in Great Falls, Montana at an Air force base there and i came across an interesting article I wanted to share wit you all. The article takes place in Valier, Mt which is about two hours west of Great falls on highway 15. I am based in Great falls, but I work out by valier guarding some valuable assets out there so this really struck me as being weird. I will paste a little bit of the article here and provide a link for those of you who are interested in reading more.

Valier rancher John Peterson and his wife were recently headed out into the twilight to do some chores when they spotted her. Stopping the truck to investigate, they found the sickening, telltale signs.

The cow's udder, genitals and rectum were cut out with stunning precision. The left side of her face was carved off, the exposed bones stripped as clean as if they'd been boiled.

The rest of the article can be found here

In the article it says that these have been occuring here since 1977 so my question is this. Assume that aliens are responsible for this wouldn't you think that they would have moved on to bigger animals to experiment with. I mean if they are smart and advanced enough to visit earth wouldn't you think that by now they would know all there was to know about cows? There is a lot of history here at this base because of what occured here in 1967, so maybe they are all tied in together somehow. For those of you not familiar with what happened here in 1967 you can read up on it here

Thank you for your time