Switching your dog's food might cause issues in some dogs, so you need to make the switch correctly, so you avoid a sick pooch and paint-peelers. You might want to switch because your vet recommended a change, because you don't like how a company changed its recipe, or because you want to find something more nutritious for your dog. Whatever the reason, you definitely don't want to cause your dog to be uncomfortable – and you want it to like the new food.

Making the Transition

The transition takes about a week. Various sources use various percentages, but if you know your dog, you'll know whether to use the lower or higher percentage of the new food during the first days. If a dog suffered gas or seemed uncomfortable when you tried to introduce something new in the past, go with the lower percentages of new food to start.

Look for Adverse Reactions

An adverse reaction is not necessarily a food allergy. It could be an intolerance to the food or a specific ingredient in the food, gastrointestinal issues, or a food allergy. A true allergy triggers the dog's immune system for a specific response, and it is rarely diagnosed. Gastrointestinal symptoms include diarrhea, changes in appetite, nausea and vomiting. Your dog might also suffer from cutaneous issues, such as hair loss, different types of rashes, skin inflammation and itching.

If you suspect the new food is causing these problems, stop the new food to see if the problems go away. It could take six to eight weeks after stopping the new food for symptoms to disappear. If the symptoms persist after eight weeks, the problem is not the new food.

Combatting Adverse Reactions

If your dog has minor adverse reactions, you might have to transition slower. A typical transition schedule is as follows:

• First day: 20 to 25 percent of the new food mixed with 80 to 75 percent of the old food.
• Third day: 40 to 50 percent of the new food mixed with 60 to 50 percent of the old food.
• Fifth day: 75 to 80 percent of the new food mixed with 25 to 20 percent of the old food.
• Seventh day: 100 percent of the new food.

If you are using the lower numbers, add another day – the sixth day, you should feed 80 percent of the new food with 20 percent of the old food before moving to 100 percent of the new food.

If your dog exhibits a reaction on the third day, go back to the amounts on the first day for an additional three or four days. Then try the amounts on the third day. If your dog adjusts to the third-day amount and shows adverse reactions when you increase the amount to 75 percent, go back to the 50 percent for an additional three or four days.

Switching Cold Turkey

If you need to switch cold turkey because of a medical issue and your dog seems to have minor trouble adjusting to the new food, you can try adding probiotics to its food. If you have to switch slowly, keep in mind that it is better to switch slowly than not at all.

Sources

https://www.akc.org/expert-advice/nutrition/right-way-switch-dog-foods/

https://www.proplanveterinarydiets.ca/sites/g/files/auxxlc696/files/2021-02/180107_PPPVD-Fecal-Scoring-Chart-UPDATE-EN-FINAL.pdf

https://www.caninejournal.com/changing-dog-food/

https://www.petmd.com/blogs/nutritionnuggets/jcoates/2012/feb/how_to_switch_dog_foods-12550