Your Dog's Digestive System Explained

As omnivores, the digestive system of the dog can digest a wide range of foods, including plant-based foods. Due to the fact that plant matter is more difficult to digest than meat, domestic dogs actually have a longer digestive tract compared with true carnivores such as cats.

The Digestive Process Begins with Smell

The digestion process begins before the dog even begins to eat their food. Anticipation of a meal, or the smell and sight of food stimulates the production of saliva, which aids in digestion and helps with swallowing.

Into The Mouth

The dog then uses their mouth and teeth to pick up food and begin eating. The front teeth (incisors) are suited to picking up individual pieces of food, while the larger teeth at the back are better for grinding and chewing.

The tongue also plays a part in this process, helping to move the food around the mouth and position it for chewing.

Down The Oesophagus

Once the food has been chewed into smaller pieces, the dog swallows and the food travels down the oesophagus to the stomach. It's important for pet parents to be aware that small bones such as chicken necks or wings can easily become lodged in the oesophagus and cause a blockage or injury, so it is best to avoid feeding these.

The Stomach & Intestine Begins Digesting Proteins

Inside the stomach, gastric juice is produced which contains mucus, hydrochloric acid and enzymes to begin digesting proteins.

The walls of the stomach are muscular and contract to physically mix the food as it is broken down.

When the gastric contents are thoroughly mixed they form a thick milky liquid known as chyme. The chyme then passes through the pyloric sphincter of the stomach into the first part of the small intestine, the duodenum.

In the duodenum, more enzymes are secreted from the intestinal wall and the pancreas, including proteases for protein digestion, amylase for carbohydrate digestion and lipase for fat digestion.

Pancreas, Liver & Intestines

The pancreas also secretes sodium bicarbonate, which neutralises the acidic chyme to allow the digestive enzymes to function.

Bile, which is produced in the liver and stored in the gallbladder, is also released into the small intestine to help break down fats into smaller globules ready to be digested by lipase from the pancreas.

Once proteins and carbohydrates have been broken down by the digestive enzymes, their components are able to be absorbed across the wall of the intestine into the bloodstream. Fat is absorbed into the lymphatic system before it eventually ends up in the blood.

Once the food makes it to the large intestine, the bulk of its nutrients have been digested and absorbed. In the large intestine, water is absorbed and there is some fermentation of fibre by bacteria, known as the gut microbiome.

An imbalance of desirable and undesirable bacteria within the gut microbiome can result in excessive fermentation causing symptoms like flatulence or diarrhoea.

Out The Rectum

Once the undigested remnants of the food reach the end of the large intestine, they constitute faeces, which are stored in the rectum and passed through the anal sphincter when your dog takes a toilet break.

There are a variety of factors that can cause upsets to the digestive systems of dogs, including stress, diet and bacterial imbalance in the intestines. By feeding a high quality diet, particularly one designed to support optimal digestion, like Hill's Science Diet, you can help to keep your dog feeling happy and healthy inside and out.