What is the ruling on Zakat when an animal is stipulated in debt (in the description of the employment contract)?

Primary text

If the herder is employed for a described animal owned by the employer but specified in obligation (Dhimma), the contract is valid. When the Hawl passes, if the employer has no other property requiring Zakat except this stipulated obligation, the ruling depends on whether debt prevents Zakat in publicly known wealth, which will be addressed later.