What are some recent innovations in beef cattle breeds?

Currently cattle are at their best conversion rate in history. That means they have been bred to create an animal that puts on the most pounds for the least feed. There are exceptions - longhorns and some of the other "heritage" breeds, but for the most part the mainstream beef herds have chosen to select for conversion rate and as a result, America can produce more pounds of beef on less feed than any other nation in the world.