I saw this episode of Bob's Burgers last night. Basically, Bob is nearing his 100000 burger, and some jerk shows up with a cow to protest animal cruelty and asks "how many cows had to die for your burgers?"
First, let's take the National Cattlemen's Beef Association beef research guide, and accept their calculations for a standard 1300-pound steer. Summing their numbers and then noting after-the-fact that they do it themselves on page 7, this results in a cow containing 638.2 pounds of meat, of which 265.1 pounds are ground beef. This is where you have to decide if Bob can offset future ground beef with the other cuts contained in the cow or not (is he charged .41 cows or 1 cow per cow). Assuming he's making standard quarter pound burgers, this results in either 39.173 cows (assuming he's allowed to offset) or 94.304 (if all cows that contribute count).
That's way lower than I would have guessed beforehand.
