The most common and most likely answer to this crossword clue is the 12 letter word THOROUGHBRED
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result THOROUGHBRED
- Racehorse, however unkempt, initially black, then scarlet
- Both confused about ungroomed roan horse
- Horse soldiers brought back in but multiplied
- Pedigree herd bought or flogged
- Meticulous with money, wanting a horse
- Pedigree during race almost turned outside ring
- Pure oxygen smuggled in using barrels of blood?
- Brother in comprehensive education that contests steeplechase?
Buddy explains!

The straight part
We know that "Pedigree" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pedigree = thoroughbred.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does THOROUGHBRED mean?
THOROUGHBRED noun- A horse of a breed derived from crosses between Arabian stallions and English mares, bred for racing. (usually capitalized: Thoroughbred.)
- Any purebred horse.
- A person of uncommon strength or endurance (like that of a thoroughbred horse).
- A well-bred person.
- Bred from pure stock.
- Well-bred and properly educated.