First of all, a cow has only one udder. Said udder is divided into four quarters, each a separate mammary gland, and each with its own teat. Ergo, four teats per cow.
Now if the tour guide insisted they were all cows and not bulls or steers, I guess I would believe her. Certainly if she was wrong, someone would have corrected her long ago. That "thingy hanging down where it is" is probably the cow's navel. On some breeds they have lots of loose skin to help dissipate heat, and the navel tends to hang low. I have to admit, I would need to examine that animal a little more closely to know for sure.
Skip, did she mention what breed these cows were? They look like some sort of cross between a Brahma and a Texas Longhorn.