What you need to know about the canine digestive system

June 2, 2026

The canine digestive system is different from humans, which is why it’s important to understand how dogs digest their food. This knowledge helps you provide the right diet and recognize when something might be wrong.

Pups’ Immunity

The first few months of a puppy’s life are called the “immunity gap,” during which they are more vulnerable to digestive issues such as poor nutrient absorption or imbalances in gut microflora. This is also the time for vaccinations and routine vet checks.

“Maternal immunity is bestowed on the puppy…in its mother’s ‘first milk’. The mother’s body will produce colostrum—a specific type of milk that is highly concentrated in antibodies—that will help support their little one’s immune system.”[1]

Digestive Health in Puppies

Puppies grow rapidly—about 20 times faster than adult dogs—and need roughly three times more calories per kilogram of food[2][3]. A special growth diet is recommended to support their development and avoid overstressing their small stomachs.

Feed puppies four meals a day until around four months.
Switch to three meals daily until six months.
Then transition to two meals a day.

Monitor for signs of sensitivities to the food, and consider formulas like Addiction Vet Diets Salmon Bleu for Puppies for optimal gut support.

Diet for Adult Dogs

Small breeds usually reach adulthood around nine months, while large breeds may do so at 15 months. Adult dogs require specially formulated diets that meet their nutritional needs while supporting gut health.

High-quality protein sources support digestion and maintain healthy muscles.
Probiotics help rebalance gut microflora.
Adequate fiber aids nutrient absorption without stressing the gut.
Large breeds benefit from appropriately sized kibble to prevent choking.

High-Quality Sources

Proteins from premium sources maintain a dog’s digestive system and help prevent sensitivities from worsening. Addiction Vet Diets formulas use responsibly sourced ingredients from New Zealand, including novel proteins like salmon, lamb, venison, brushtail, duck, and kangaroo.

Fiber content is balanced for adult dogs to support smooth digestion. Consider your dog’s breed and lifestyle when selecting a diet. Large breeds benefit from larger kibble sizes to reduce choking risks.

Senior Years

Dogs reach senior age at different times depending on breed: small breeds around 10–12 years, large breeds around 5–6 years, though many veterinarians consider dogs senior at 7–8 years[4].

As dogs age, metabolism slows, health and stamina decrease, and caloric requirements drop. Some senior dogs may need more digestible nutrients depending on their health. Always consult a veterinarian for the best diet.

Symptoms of Digestive Problems

Senior dogs commonly experience digestive problems. Watch for:

Restlessness
Vomiting or regurgitation
Painful or bloated stomach
Refusal to eat
Diarrhea

Causes of Digestive Problems

Spoiled or fatty food, or foods unsuitable for senior dogs
Food allergies, intolerances, or sensitivities
Illness, infection, or inflammation
Parasites
Poor nutrient absorption

Digestive Care for Senior Dogs

Because senior dogs require fewer calories, divide their daily food into 4–5 smaller meals. This keeps them engaged and prevents overeating.

Easily digestible formulas are recommended by veterinarians.
Supplements such as probiotics help maintain gut health.
Consult your veterinarian on the best diet and supplements for your senior dog.

A Good Senior Diet for Dogs

According to MedicAnimal, a good senior diet is:

“A well-balanced diet that is lower in calories, higher in fiber, and provides adequate protein and fat. Specially formulated senior diets help create a feeling of fullness, manage kidney workload with lower protein if needed, and maintain digestive health with higher fiber levels.”

From The Grateful Dog, key components for senior dogs include:

Higher fiber for gastrointestinal health
Lower fat and calories
High-quality proteins
Omega fatty acids for joints, skin, and coat
Antioxidants to slow aging and ease symptoms

Addiction Vet Diets offers a range of senior dog foods with these features.

Water Intake

Fresh water should always be available. Senior dogs require approximately ½ to 1 ounce of water per pound of body weight daily. Increased water consumption can indicate health issues[6].

Food Supplements

Senior dogs may require supplements for vitamins, minerals, and electrolytes due to reduced absorption. Supplements such as glucosamine with chondroitin, essential fatty acids (Omega-3 and Omega-6), and probiotics support joint, coat, and gut health[7][8].

Addiction Vet Diets believes that understanding your dog’s dietary needs is the first step toward a long and healthy life. Explore our Nutrition Advisor to find the best diet for your pet.

We produce and distribute dog and cat food under strict safety standards. Our formulas are available through selected retail partners and via contactless online delivery in New Zealand, Singapore, and the USA.

Follow Addiction Vet Diets on Facebook and Instagram for pet health and nutrition updates.

References:

Further Reading:

Back to blog

Your cart is empty

Hypoallergenic