The Ranch Guild will keep your pet. You can not take your pet out to sojourn with you after the 30 day term expires.
After renewing the contract by paying the pet food fee, you will be able to take your pet out again.
While your pet is kept in the Ranch Guild, the pet's dice will keep increasing up to 99 dices. In addition, your pet's life level will not be reset to zero but remain the same level as it was right before the contract expired.