Dog Digestion:Understanding is Key to Dog Food Choice
Coming from a health care background, I am sometimes guilty of assuming that everyone knows how our bodies work. I was inspired to write this item after noticing a question that had been posted online on a message board.
Digestion is the process by which food materials are broken down into their simplest forms so that nutrients can be absorbed into, and utilized by, the body. Understanding how the dog digestive system operates is key to understanding the best choice of dog food for your dog. One way to achieve this understanding is to compare the dog digestive system with our own.
Dogs are primarily meat eaters (carnivores), although like us, they can eat other types of food. It’s the teeth that tell the difference: while our teeth are those of a true omnivore, with flat molars designed to grind and chew nuts, grains and other plant matter, dogs’ teeth have the sharp blade-like edges that are meant for cutting and tearing raw meat. They don’t chew their food the way we do, but rather swallow it in whole chunks. This is because no digestion of the food happens until it reaches the dog’s stomach. We humans have to chew our food in order to break it down and mix it with saliva, because our saliva contains the digestive enzyme ptyalin, which starts the digestion of carbohydrates.
The stomach is a reservoir with strong muscular walls, which churn the food around in order to mix it with the hydrochloric acid, digestive enzymes and mucus secreted by the stomach lining. The mucus serves to protect the stomach tissue from itself being digested. The food is held and mixed in the stomach until the initial stage of digestion is complete and the food has gained a liquid consistency like thick soup. This liquid is known as “chyme.”
The chyme leaves the stomach through a strong, circular muscle called the “pyloric sphincter” and enters the duodenum, which is the first part of the small intestine. Here, further digestion takes place, with more enzymes added from the pancreas and liver. From this point on, the dog digestive system and its human counterpart do not differ much. Most digestion is completed in the duodenum, and absorption of nutrients takes place in the remainder of the small intestine.
In the large intestine there is some bacterial activity that serves to break down any remaining fibrous material, which can sometimes lead to flatulence. Dogs don’t deal with fibre very well and undigested plant matter can sometimes be observed in their faeces. The function of the large intestine is mainly to absorb moisture so that the stool becomes formed, and to act as a storage place for the stools until they can be voided via the anal sphincter.
