Inside Out: Understanding Your Dog’s Digestive Tract
Aside from maybe sushi or beef tartar, most meat on a human’s plate is cooked. However, it is not uncommon, and most experts agree, the meat in your dog’s bowl should be raw unless there is a medical reason requiring the meat be gently cooked. The reason for this is that dogs, while mammals like us, have a fairly different digestive tract than humans.
QUICK FACT: Did you know that the dog’s intestinal tract is the smallest of mammals which means food doesn’t stay long? From start to finish, the digestive process takes about 8 hours.
Understanding your dog’s digestive tract and how it is different than yours is very important when selecting the appropriate diet for them. Since we only know what we know, we tend to feed our dogs they way we feed ourselves. It makes the most sense to us that way. However, this article will explain how it is that your dog can eat raw organ meat, but not raw carrots. Yes, that is correct, dogs should not eat raw vegetables.
The Difference Inside
Dogs have key differences in their digestive tract that every owner should know about. Not just in the obvious appearance of the way the dog’s teeth look, but also in their jaw’s conformity and the way their saliva works. Let’s start by looking at the mouth of a dog.
Teeth & Jaw
Dogs have 42 teeth in their mouth compared to just the 32 in a human’s mouth.
Dog’s teeth are specifically formed to rip/tear off and shred large chunks of meat as well as break and crush bones. Additionally, their jaws only move in an up and down motion, allowing them to have stronger bite to help render kill.
Due to our more plant-based omnivore diet, human teeth are flat and our jaws move in a rotating motion which allows us to grind food in our mouth. That process is called mastication.
A dog’s stomach is designed to break down raw meat and bones. Because of this, some enzymes that help break down certain other materials do not exist in the dog’s stomach.
Human saliva contains enzymes such as amylase and lipase to begin the digestive process in breaking down bonds in grains, plants, and fats while dog saliva is meant to coat food to allow it to slide down the throat in those large chunks, up to a certain size, as well as secrete an enzyme called lysozyme that helps to kill bacteria.
The Digestive Journey
After passing through the esophagus, food lands in the stomach where there are more key differences between humans and dogs.
In both humans and dogs, the stomach secretes hydrochloric acid and pepsin to help break down foods. Human stomachs have an average pH of 5 which means that the acid content is weaker allowing various enzymes in the stomach to continue to help break down the complex bonds of grains and plants.
On the other hand, the dog’s stomach contains a much stronger acid (average pH of 1) allowing the acid to not only dissolve and break down bones, but also the fat and meat so that nutrients will be able to be absorbed in the intestinal tract. This lower pH also makes the stomach an inhospitable place for most bacteria, further aiding in killing off potential pathogenic bacteria that could cause sickness.
When food leaves the stomach, it goes into the small intestines where most nutrients are absorbed. Canine intestines are much shorter than humans, measuring 20-80 cm, whereas the human intestinal tract measures 1.5 m in length. Why does the length of the intestines matter?
Due to the smaller intestinal tract length, food doesn’t have as long of a trip to take and thus not as many nutrients are absorbed. If the food isn’t properly broken down when consumed, it just goes straight out into the feces. This is why you may find identifiable items such as blades of grass, carrots or corn kernels in your pet’s poop.
A shorter intestinal tract also means that the food passes through quicker. In dogs, food is fully absorbed by the body and excreted in 24 to 48 hours. Compare that to humans where it takes humans an average of 3 days to fully process, digest, and excrete food. This is why it is so important to feed your dog nutrient dense foods that are easily (and quickly) digestible. Their body simply doesn’t have the time to break down processed foods and extract vital nutrients.
From the small intestines, the remaining indigestible material is turned into fecal material and transported to the large intestines or colon. In the colon, last minute nutrients are absorbed as well as water. And you know the end result of digestion – Don’t step in it!
The Role of Diet and Nutrition
Diet plays a huge part in food absorption times. When prepared correctly, raw, canned, and homemade diets take less time to digest, 4 to 6 hours to be exact, because the food is already broken down and has ample water which is needed for the digestive process. Dry or carbohydrate-rich diets, on the other hand, take longer to digest because the complex bonds are harder to break down. This is why you can get away with only feeding your pet twice daily with dry food. If you are feeding your pet a raw or home cooked diet, it’s best to feed smaller portions at least 3 times daily.
While meat is best fed raw in healthy dogs, vegetables should be cooked. This helps begin the digestive process and starts breaking apart bonds to allow nutrients to be extracted. If you’re feeding a home cooked diet, make sure that grains and vegetables are cooked and then processed (such as pureed in a blender) to ensure your dog receives the full benefits of the vitamins and minerals contained in the food.
The Cooking Process
Lastly, a note about the cooking process and how heat impacts nutrients in food. Nutrient and water loss is inevitable in nearly every cooking process. When food is heated, the vitamins and fat content are affected, some more than others. Protein structure is also modified.
Fats have what are called a “smoke point” which is the point at which their chemical structure is modified. Coconut oil has a high smoke point (350 degree fahrenheit) while beef fat has an even higher smoke point of 540 degrees Fahrenheit and chicken fat can withstand heat up to 400 degrees Fahrenheit. By keeping fats below their smoke point, you avoid changing their chemical structure.
Vitamins and minerals are lost when food is frozen, cooked and even re-heated. In most cases, by reserving and consuming the liquid created from the cooking, you can retain as much as 25% of some vitamins or minerals lost. Two vitamins most impacted by cooking are Vitamin C which loses nearly half and Folate which loses up to 70% when cooked. One mineral most affected by cooking is copper which loses as much as 45%. Minerals and vitamins can be added back in through supplements ensuring the meal is balanced.
Protein structure is also changed when exposed to heat. Just look at egg if you want to understand how this is possible. The raw yolk of an egg looks very different from a scrambled egg. Another example is the effects of heat on collagen. When cooked long enough, the protein becomes gelatinous. We will continue this discussion in another article as the topic is complex and lengthy. In the meantime, for more information on how heat affects protein structure in animal products, you can read this article from The Journal of Nutrition.
But cooking is not always bad. Cooking certain foods can make nutrients more available for the body. For example, cooked carrots have more carotenoids than raw. And as discussed above, cooking vegetables and grains is essential to break down the foods before feeding them to dogs. This makes sense when you consider that most grains and vegetables eaten by your dog’s ancestors came from the intestines of their prey which meant it was already broken down and predigested.
So what should be in your dog’s bowl? The answer depends based on a dog’s age, weight and medical condition. Generally speaking, a healthy meal for your dog would ideally include raw or gently cooked meat and organ with ample, but not too much, fat; raw ground bones (never feed cooked bones); gently cooked and processed vegetables and grains; and vitamins and minerals necessary to balance it all out. Remember to add vitamins and minerals after cooking when the food is room temperature or cold. Your veterinarian or canine nutritionist can help you craft a meal specifically designed to meet your dog’s nutritional needs.
Disclaimer: We are not veterinarians, canine nutritionists nor have any formal training in the medical or nutrition field, including veterinary. The information presented on the Dragonfly Dog Bowl website and blog is for conversational purposes only. We do not diagnose or treat any conditions. None of the content should be interpreted as medical or nutritional advice. Always consult a veterinary professional regarding your dog’s specific needs and never feed any foods, supplements, or items discussed on this website or take any actions without first speaking to your veterinarian.