According to Evaluation of selected high-starch flours as ingredients in canine diets:
Cereal grains represent 30 to 60% of the DM of many companion animal diets... crystallinity and form of starch are variable and can cause incomplete digestion within the gastrointestinal tract.
To be clear, this site is an advocate of grain free dog food. Your dog does not require any cereal grains to be healthy, but, with that said, some dogs do just fine with some grain in their diet. Here is a list of cereal grains in dog food and a review of their value and use in your dog's diet.
If you have your heart set on feeding your dog grains, give him rice—whole grain rice, specifically human grade. Rice is one of the more tolerable grains that is commonly used in dog food. But, don't confuse rice, or whole rice, with rice flour. While rice flour is a decent substitute for wheat flour because of its lack of gluten, it is still a basic starch.
Whole rice is the most nutritionally complete of the cereal grains for dogs, but rice bran is another form of rice. Rice bran is a moderately healthy by-product of rice, but if you do choose to feed your dog rice, it is best to serve only whole grain rice. Further, lower value rice products are known to contain low levels of arsenic [2,3].
Corn is the most common of the cereal grains to be used in dog food processing because of its mass availability and affordability. Because of its strong starch-protein matrix, it has low digestibility and very low nutritional value, while the carbohydrate value for corn is high. Your dog possesses very little biological mechanisms for metabolizing and digesting corn and for this reason, your dog should never be fed any diet containing corn, corn meal, corn gluten meal, or other corn by-products.
Wheat is a problematic cereal grain for dogs. Wheat is difficult and sometimes impossible for your dog to digest. Wheat and wheat gluten are known to be a cause for food allergies in dogs.
Barley is one of the more acceptable cereal grains that is used in dog food. Barley is high in fiber making it a low glycemic cereal grain.
Millet, although classified as cereal crops, are seed grasses. Millet provides B Vitamins and is good a gluten-free source of fiber, yet still difficult on digestion. Millet should not be fed to dogs with thyroid issues due to its thyroid inhibiting properties.
Flax is not a cereal grain, as it is sometimes confused. Rich in soluble fiber though, flax is known to be a great plant source of omega-3 essential fatty acids, although this type of omega-3 is unavailable to your dog. Dogs have no way of converting inactive ALA into usable omega-3. For this reason, dogs should only be given fish oil for omega-3.
That said, as a source of soluble fiber, flax is a healthy ingredient in dog food
Oats are a high fiber cereal grain, and if minimally processed, provide some good nutritional value. The fiber content of oats can be beneficial for a dog's colon health, however, a dog's colon is better supported with probiotics than with cereal grains.
Cites and References
- J Anim Sci. 1999 Aug;77(8):2180-6. Evaluation of selected high-starch flours as ingredients in canine diets. Murray SM1, Fahey GC Jr, Merchen NR, Sunvold GD, Reinhart GA.
- Hassan FI, Niaz K, Khan F, Maqbool F, Abdollahi M. The relation between rice consumption, arsenic contamination, and prevalence of diabetes in South Asia. EXCLI J. 2017;16:1132–1143. Published 2017 Oct 9. doi:10.17179/excli2017-222
- Food and Drug Administration. March 2016. Arsenic in Rice and Rice Products Risk Assessment Report.
- Various Possible Toxicants Involved in Thyroid Dysfunction: A Review Jagminder K. Bajaj, Poonam Salwan, and Shalini Salwan. J Clin Diagn Res. 2016 Jan; 10(1): FE01–FE03.
- Dietary Flaxseed in Dogs Results in Differential Transport and Metabolism of (n-3) Polyunsaturated Fatty Acids John E. Bauer, Brent L. Dunbar, Karen E. Bigley. The Journal of Nutrition, Volume 128, Issue 12, December 1998, Pages 2641S–2644S, https://doi.org/10.1093/jn/128.12.2641S