The property security guard lost my dog! What legal responsibilities should the property bear?

According to the actual situation, because the dog belongs to the owner's personal property, if the property company bears the liability for breach of contract for the loss of the owner's dog, the owner may require the property company to bear the liability for breach of contract.

Relevant provisions of the Property Management Regulations

Article 35 The owners' committee shall sign a written realty service contract with the realty service enterprise selected by the owners' congress.

Property service contracts shall stipulate property management matters, service quality, service fees, rights and obligations of both parties, management and use of special maintenance funds, property management premises, contract term, liability for breach of contract, etc.