Lost Pet: Teddy

Circumstances

 We were in the yard like every morning. (3 acres)  He was right with me while I walked around our large yard.  I was checking my greenhouse and and a few minutes later I heard on horn blow down on our road.  I immediately looked for Teddy but could not see him.  I have called him and looked for him up and down our road and in the woods near our house but no sign.  I'm worried that someone picked him up from our yard.