In my game tamed animals despawn after they have already been tamed/bred. Dogs and cats are the only animals not effected. After I have tamed animals and I leave them in a fenced in area and come back later, they will have despawned, even if they are wearing a saddle. This also includes fish and axelotls that have been put previously in buckets and then released in enclosed areas. Animals that I have also bred (cows, pigs, sheep, foxes..ect) despawn even when they are attached to leads. This affects all my animals in mincraft, except dogs and cats.

I hope you can fix this issue! Thank you for your time and have a great rest of your day. - Hannah