Losing a pet is not something any pet owner wants to experience, but, unfortunately, it can occur despite a pet owner's best efforts to prevent it. Collars equipped with appropriately fastened metal ID tags - that have your pet's name and your contact info engraved on them - are a good starting point for ensuring that if your pet ever does get lost, it stands a good chance of being returned to you promptly and safely. The next level of intervention is to have your veterinarian microchip your pet so that if your pet losses their collar, the person who finds them can take your pet to a local veterinarian's office and the chip can be scanned. A coded number programmed by the chip manufacturer is pulled up on the scan and linked to the contact information you provided to the company at the time that the chip was placed under your animal's skin.
If you have lost your pet, contact all local veterinarians in the geographic area where you last saw your pet, and ask them if anybody brought in an animal that matches your pet's description. You can also ask them to display a lost pet flyer in their office, and it's probably also a good idea to place flyers in the community where your pet was last spotted.
Many local newspapers will run a free lost pet ad, and this is worth looking into. Also, scanning the newspaper ads for lost pets is another way to see if anyone has found your animal and if they’re now trying to get in touch with you.
Finally, contacting animal control (ie "the pound") is important, because if someone turns a lost pet in to animal control, and no one claims them, they are sometimes euthanized by the end of a four day stay if there are too many animals for the available space.
Below are some links to websites that provide additional information and resources. Best of luck, and you have our heartfelt sympathy.