Whipper-in

“[…] I shall take to hunting a pack of hounds myself after this.” “Do, my dear, and I'll be your whipper-in. I wonder whether Mrs. Proudie would join us.”

Source: wiktionary

The other servant was an old man, who had been whipper-in to a baronet in the next county, and knew as much of the ways of wild animals as Burton did of those of his horses; […]

Source: wiktionary

Now the clerk […] saw the hunting man pass, and presently saw lots more of ’em, noblemen and gentry, and then he saw the hounds, the huntsman, Jim Treadhedge, the whipper-in, and I don’t know who besides.

Source: wiktionary

He heard the chaunting voices of huntsman and whippers-in; the noises of motor-cars moving slowly along the hard-rutted trackway, the old canal-bed, above the right bank of the river;

Source: wiktionary