The most common and most likely answer to this crossword clue is the 10 letter word WHIPPER-IN
I've seen this crossword clue in The Guardian
W
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More clues leading to the result WHIPPER-IN
- Secure cages in, for each person controlling hounds
- Hounds manager that’s optimistic but not around during success
- Dog handler with more in secure pens
- Triumph over more modern dog-handler
- Wife more trendy, fashionable, a huntsman’s assistant
- Wife more trendy, fashionable, a huntsman's assistant
- Acquire clothing more fashionable for dog-handler
Buddy explains!

The straight part
We know that "Dog handler" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dog handler = whipper-in.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 WHIPPER-IN mean?
WHIPPER-IN noun- A huntsman who keeps the hounds from wandering, and whips them in, if necessary, to the chase.
- One who enforces the discipline of a party, and urges the attendance and support of the members on all necessary occasions.