Edible Cacti

I know Prickly Pear fruit and pads are edible. Does anyone know if dragon fruit or Peruvian Apple cactus trunks/stems are edible for livestock?

ok. Found out dragon fruit stem is edible. But peruvian apple cactus?

No idea about that Peruvian variety. Here in the Sonoran desert, I know that Nopales (what you probably refer to as prickly pear) are only edible for humans when they are early shoots in the spring, before the spines harden. The soft green flesh is actually quite sweet. The javelina here eat the whole plant when the summers get so hot there isn't anything else available. Likewise the rabbits will eat anything when they get hungry enough.