noun
pedigree document; pedigree paper
Official document certifying the lineage of an animal, especially dogs and cats. Common in contexts of purebred pets and breeding.
この子犬には血統書が付いています。
This puppy comes with pedigree papers.
血統書を確認してから購入を決めた
I decided to buy after checking the pedigree document.
血統証明書 is a more formal synonym for 血統書, often used in official contexts.
Compound of 血統 (bloodline, pedigree) and 書 (document, writing).