Plants are fertilizer because they have collected the nutrients from the soil that they needed for growth and concentrated them. They break down and form humus which has a great ability to retain both nutrients and water and allow excessive water to drain. You can add them as green as long as you don’t add over an inch thick in the planting hole without allowing to compost first since thicker layers will create heat. Brown materials do well when urine is later added. I can not imagine what would cause all those things to happen to cattle.