Animals and pets despawn on game change

Whenever a new update occurs or I log back into my game, or even occasionally moving out of a rendering distance, my animals and pets (such as dogs) despawn. I would understand them despawning if I hadn't of tamed them or put name tags on them or bred them, but this issue continues to occur even on entities that have name tags or taming properties. If you could help with this issue, that would spare me from a great deal of stress and tediousness within my gameplay. Love the game, keep it up.