In which scenario is written permission required before performing a procedure on an owned animal?

Written permission is typically required before performing euthanasia on an owned animal because it involves the intentional ending of the animal's life. This procedure is a sensitive and significant decision for pet owners, as it reflects their responsibility for their pet's welfare. Obtaining written consent ensures that the owner is fully aware of the procedure's implications and has made an informed choice regarding the animal's care.

In contrast, emergency resuscitation is often performed without prior consent since it is a life-saving action taken in critical situations where immediate intervention is necessary, and the animal’s owner may not be readily available to give permission. For surgeries, verbal consent is usually sufficient in many settings, especially if the owner has already signed a consent form for general surgical procedures. Similarly, for any medical services, consent might be verbal or implied based on the established veterinarian-client relationship and typical practice protocols. Therefore, written consent for euthanasia stands out as a critical requirement due to the nature of the procedure and its ethical implications.