Notice the yellow links attached to the ear tags of these cows. The links are used at this dairy in California to identify cows by milking string. But, the links also could be used to designate hospital cows or cows receiving BST injections. So far, the dairy can only get its hands on four different colors, but that will change in the near future. A manufacturer in nearby Turlock, Calif., plans to mass-produce the 1.5-inch plastic links in eight different colors. If you are interested, contact Volk Enterprises at (209) 656-2700.