Recognise what you are seeing and act on the pattern
Kennel cough is the common name for a contagious respiratory infection dogs pick up where dogs mix — boarding kennels, day care, group walks — and its calling card is a harsh, dry, honking cough, sometimes ending in a retch that owners mistake for something stuck in the throat. Symptoms often appear a few days after the stay rather than at collection, so a dog who came home well can start coughing midweek. He may also sneeze, have a runny nose or weepy eyes, and yet seem largely himself. You cannot confirm the cause at home, and other conditions can cough too, so treat the pattern — recent boarding plus a new persistent cough — as reason to rest him and involve your vet, not as a home diagnosis.
Rest him and protect other dogs from day one
The kindest and most responsible response is also the simplest: pause his social life. Skip dog parks, day care, group walks, and visits to friends' dogs, and walk him on a lead at quiet times, keeping distance from other dogs and warning owners who approach. At home, favour rest over exercise while he is coughing, because excitement and pulling trigger coughing fits. Swap his collar for a harness on the short walks you do take, so nothing presses on an already irritated throat. Keep his air clean — no smoking near him, go easy on scented sprays and dusty cleaning — and let him drink freely, as a soothed, hydrated dog coughs less violently than a dry, excited one.
Call the vet and know the same-day warning signs
Phone your vet, describe when it started, how it sounds, and that he has recently boarded; the practice may want to examine him, may advise monitoring at home, or may ask you to wait in the car or a separate area to protect other patients, so follow their lead. Seek same-day veterinary care without waiting if his breathing becomes fast, noisy, or laboured, if he stops eating, becomes lethargic or weak, runs a feverish warm and quiet spell you cannot rouse him from, produces discoloured discharge, or coughs until he cannot settle. Puppies, elderly dogs, flat-faced breeds, and dogs with existing heart or airway problems deserve a lower threshold still, because a mild infection in a sturdy adult can hit them harder.
Tell the kennel, and keep a simple symptom record
Let the boarding kennel know promptly. A good kennel wants this information: your dog may have caught the infection there, or brought it with him, and either way other owners need the chance to watch their own dogs. Note the date symptoms started, how often he coughs, his appetite, energy, and temperature of behaviour day by day — a short record turns a vague worry into clear information for the vet if he does not improve. Most uncomplicated cases settle over one to three weeks with rest, though the cough can linger; ask your vet when he may safely mix with other dogs again rather than guessing, because he can remain contagious beyond the noisy stage.
Review the stay before you book the next one
Once he has recovered, think back over the stay without rushing to blame: group housing always carries some respiratory risk, even in a well-run kennel. Ask the kennel what vaccine cover they require from guests, how they isolate a dog who starts coughing, and how they notify owners — their answers decide whether you board there again or choose a quieter option such as a sitter next time. Keep his vaccination history, boarding dates, and the record of this illness together in his KinsLe Pet Passport, so any vet or future boarder can see the full picture at a glance.