A new law about animal feed came to the rescue, and enabled us to feed the livestock this food

Here’s a riddle: What could be the halachic problem with giving animals animal food? And how can it be avoided?

You know about the issur of basar b’chalav, mixing meat and milk. But you may not know that if the milk and meat were merely mixed together, they would only be assur b’achilah, forbidden to eat;  if they were cooked together, they would also be assur b’hanaah — it would be forbidden to gain any benefit from such a mixture.

Are you wondering what benefit you could get from a mixture of meat and milk, if you aren’t eating it? Well, you could sell it to a goy and make money, or… feed it to your animals. Those are ways you could get hanaah, benefit, from a forbidden mixture. But here’s another interesting, lesser-known fact: if the meat comes from an animal that isn’t kosher, it remains only assur b’achilah, even if it’s cooked together. Only milk cooked together with kosher animal meat becomes assur b’hanaah.

Once, I discovered a very big problem with animal feed. It contained whey protein (which comes from milk), and it also contained animal fats (which, obviously, come from animals. Yes, the animal feed given to livestock contains animal fats from other animals). Both ingredients were cooked together. And, as you now know, that meant that it would be assur for Yidden to feed this to their animals! It would be an issur d’Oraisa of basar b’chalav, chas v’shalom!