No person shall be permitted to adopt a dog or cat from the City pound unless the person adopting the dog or cat first agrees to have the animal sterilized in accordance with the requirements of Section 162.20, Code of Iowa. Any person who fails to have the adopted dog or cat sterilized shall be deemed to have committed a municipal infraction. Any person who fails to comply with a sterilized agreement or to return the adopted dog or cat within 24 hours after receiving a demand letter requiring proof of sterilization shall be deemed to have committed a municipal infraction.