Ornery Tumblewagg

“Saddled” isn’t an ability that a creature has. It’s just something true about that creature. It won’t stop being saddled until the turn ends or it leaves the battlefield.

“Saddle N” means “Tap any number of other untapped creatures you control with total power N or greater: This permanent becomes saddled until end of turn. Activate only as a sorcery.”

An ability that triggers when a creature “attacks while saddled” will trigger only if that creature was saddled when it was declared as an attacker.