When to Switch a Great Dane From Puppy Food? Vet-Approved Tips

By Nicole Cosgrove · Reviewed & fact-checked by Dr. Maxbetter VizelbergVet Approved

Reviewed & Fact-Checked byDr. Maxbetter VizelbergVeterinarianMaxbetter grew up in New Orleans, Louisiana, and has been interested in veterinary medicine since childhood. Being read Russian children’s stories about “Doctor Aybolit” by his grandmother, interning at the Israeli Wildlife Hospital, and working at numerous small animal hospitals have all been part of his lifelong love of animals. Maxbetter currently practices in New York City, and enjoys educating others to help them give their animals the best possible lives. He always strives to provide excellent medical care to his patients. Outside the clinic, he can be found playing basketball and soccer, performing his rap songs at open mics, and going on hikes with family and friends.View authorThe information is current and up-to-date in accordance with the latest veterinarian research. Read about our vetsUpdated on October 7, 2025

Like children, our pets grow so fast. It seems like they go from adorable puppies to full-sized dogs overnight. This is much more noticeable if your dog is a giant breed like a Great Dane. While their size and features quickly become mature and adultlike, their bodies are still developing and growing. It can take as long as two years for your gentle giant to be fully grown.

While some breeds can be transitioned to adult food by 12 months old, this is not the case with a Great Dane. Great Danes are a giant breed that should not be transitioned to adult food until 18 months or older.

How to Transition Your Great Dane from Puppy to Adult Food

Obviously, if it is not broken, do not fix it. It may not be necessary to switch your dog’s food. If you feed your dog high-quality food and are not overweight, you may need not change its food.

If you want to switch to an adult or better-quality food, however, the transition should be made slowly and properly. Doing so will help to limit digestive upset so the change is comfortable and enjoyable for your pet.

Here is a 4-day plan you may want to consider when you are switching foods.

Meal 1: 25% new food and 75% old food
Meal 2: 50% new food and 50% old food
Meal 3: 75% new food and 25% old food
Meal 4: 100% new food

Hopefully, the transition will be smooth and tasty for your pet. If not, seek the advice of your veterinarian—especially if the dog is exhibiting significant behavioral changes or experiencing digestive issues like vomiting or diarrhea.

It may be best to continue to use the same brand and flavor when switching from puppy to adult food. It can help to lessen the degree of side effects and prevent allergic reactions to the food.

great dane dog eating dog food from the feeder bowl — Image Credit: Alicia Fdez, Shutterstock

When Is a Great Dane Fully Grown?

Great Danes are considered a giant breed that can grow quickly. They are often referred to as the “gentle giants.” They were given the nickname because of their generous size and gentle demeanor.

Between the age of 18 and 24 months, the Great Dane is considered fully grown with their biggest growth spurt between four and six months old. The breed will reach its maximum height by 18 months, but it will continue to gain muscle beyond 18 months.

The Average Size of a 6-Month-Old Great Dane

Although the size of a 6-month-old Great Dane will vary by the individual, the average size of a 6-month-old pup is between 26–33 inches tall and 65 to 100 pounds.

The Veterinary Centers of America (VCA) recommend feeding your Great Dane puppy a large breed puppy food to slow its growth rate. The VCA suggests that doing so may help to reduce the risk and severity of hip and joint problems in adult Danes. A large-breed food will help your pet grow at a healthy pace and reduce the stress on its body. It will not affect the overall size of the dog, however,

The Size of a Full-Grown Great Dane

Once again, the size of your Great Dane will depend on its environment and genetics, but these are the American Kennel Club (AKC) Official Standards of the Great Dane.

Male Great Dane: 140–175 pounds and 30–32 inches tall
Female Great Dane: 110–140 pounds and 28–30 inches tall

Keeping Your Great Dane Healthy

Like most breeds, Great Danes are prone to certain health issues like bloat, hip dysplasia, joint problems, and hypothyroidism. According to the AKC, Gastric Dilatation Volvulus (GDV) is the number one killer of Great Danes. Some experts suggest that while the condition is not predictable, there are things you can do to decrease the risk of canine bloat for your pet.

Playtime and Exercise

For one hour prior to and after eating, avoid any exercise or heavy play.

Small Meals

Feed your pup small meals several times a day. This will prevent the dog from eating too much or too fast.

Conclusion

The Great Dane is a giant breed that needs to grow at a healthy rate to avoid hip and joint problems and should remain on puppy food for a minimum of 18 months. It is also important to be sure to feed it a high-quality diet and avoid heavy activity close to mealtime. As always, we recommend that you seek the advice of your vet to ensure your Great Dane is getting the proper nutrition for healthy growth and development.

Sources

Featured Image Credit: Jürg Roth, Pixabay