The phrase "new handler" refers to someone who takes on a fresh or different role or responsibility in managing or dealing with a certain thing or situation. Full definition
For new handlers using food to motivate and reward their dogs can be a trying situation. (leerburg.com)
Most affiliate member Clubs conduct obedience training sessions for the new owner and new handler as well as for the enthusiast. (gsdcouncilaustralia.org)
New handlers tend to go out and give the same level of correction with a prong that they did with a choke collar. (leerburg.com)