Every cattle feeder knows the sinking feeling. You walk the pens in the morning, and there’s one down. Maybe two. The crew pulls them, treats them, and you hope they make it. But some don’t. Bovine respiratory disease has been the number one health headache in feedlots for decades. It’s the reason your treatment budget bleeds and your closeout sheets look worse than they should. We’ve thrown metaphylaxis at it. We’ve tweaked rations. We’ve tried every vaccine schedule under the sun. And yet BRD still accounts for somewhere between a third and nearly half of all deaths in Australian feedlots. The question isn’t whether BRD matters. Everyone knows it does.…