What do cryogenics, butterfat tests, and genetic data have in common? They’re some of the reasons behind the world’s most productive dairy cows. Here’s how it all started.No matter where you are in the world, there’s a good chance the milk or cheese you’re buying is the product of the US dairy industry. Even if it didn’t come from American cattle, the cow that produced the milk could well have been inseminated by an American bull. The United States has been the world’s largest supplier of cattle...