Tracheal collapse
Tracheal collapse is most commonly found in small dog breeds , including the Chihuahua , Pomeranian , Toy Poodle , Shih Tzu , Lhasa Apso , Maltese , Pug , and Yorkshire Terrier . 
<triplet> Chihuahua <subj> dog <obj> subclass of <triplet> Pomeranian <subj> dog <obj> subclass of <triplet> Toy Poodle <subj> dog <obj> subclass of <triplet> Yorkshire Terrier <subj> dog <obj> subclass of