I think it is because these daily move rotations are just too close quarters for our horses.  Our quarter horse keeps wanting to herd the cows around and disrupts their cows grazing patterns.  In a less intensive system it might be very different. A neighbor grazes donkeys with his cattle to ward off coyotes but they are out on maybe 20 acre paddocks, not 0.32 acres with daily moves. I think the cows and horses might work if they had more room to separate from each other. But my system is to maximize the pounds of beef produced per acre.  The horses now have their own paddocks. The sheep are rotationally grazing in another area. We'll try putting them together with the cows later.