A dog's gut runs on a specific population of bacteria that has spent months tuning itself to one recipe. Change the recipe overnight and that population has to reorganise in a hurry, which is why the classic result of an abrupt switch is two days of loose stools and a dog that looks personally offended.
The ten-day plan
- Days 1 to 3: three quarters old food, one quarter new.
- Days 4 to 6: half and half.
- Days 7 to 9: one quarter old, three quarters new.
- Day 10: new food only.
Measure by weight rather than by scoop. A cup of a dense kibble and a cup of an airy one can differ by thirty per cent, and that difference is enough to look like an intolerance when it is really just a bigger dinner.
Slow down if you need to
Ten days is a default, not a rule. Dogs with a history of sensitive digestion, puppies, and any dog moving between very different protein sources should take two or even three weeks. Nobody has ever caused a problem by transitioning too slowly.
What is normal and what is not
Softer stools for two or three days, slightly more wind, and mild fussiness at the first meal of a new stage are all normal. Watery diarrhoea, repeated vomiting, blood, refusal to eat for more than a day, or a dog that is lethargic rather than simply picky are not. Stop the transition, go back to the food that was working, and ring your vet.
If in doubt, go back a stage and hold there for three days. The plan is a guide, the dog is the data.
Niamh Doherty, Wexfur care desk
One last thing worth saying: do not run a transition during a house move, kennel stay, holiday or the week you are starting a new medication. Change one variable at a time, or you will never know which one caused the upset.
Before you act on this
Feeding guidance here is general and assumes a healthy adult animal. Diet changes for pets with diagnosed conditions, or on prescription food, must be agreed with your vet first.
