Don't be offended if you see the word "crude" on your dog's food label. The crude fat item on your dog's food label tells you one thing: how much fat is in his food when it goes in his mouth. It doesn't provide any information about its quality or how it's metabolized.
Crude is Ambiguous
When you read the Guaranteed Analysis section of your dog's food label, you may have noticed the terms "crude fat" and "crude protein." According to the Association of American Feed Control Officials, the organization that establishes standards for the nutritional completeness of pet food, "crude" alludes to the analysis method accounting for the amount of the nutrient and doesn't the nutrient's quality. When "crude" is in front of the nutrient, it's referring to the total amount of the ingredient.
Fat in Your Dog's Diet
"Fat" often has a negative connotation, but the fact is, your dog needs some fat in his diet to provide energy, carry fat soluble vitamins and make his food worth eating. The amount and kind of fat in your dog's food affects his coat, his appetite and what kind of fat is stored in his body. Generally, a healthy adult dog should have around 5 percent fat content in his diet; puppies, lactating dogs and working dogs usually require about 8 percent fat.
When you look at the amount of crude fat in your dog's food, understand it's the amount of fat his food contains before he digests and metabolizes his food. Metabolizable energy is the amount of energy your dog gets from his food after it's digested -- it's what's left behind for his body to use. How your dog uses and stores the fat in his food -- converts it into metabolizable energy -- has nothing to do with the crude fat value and everything to do with the kind of fats his food contains.
You can compare metabolizable energy values on dog food labels to understand how different foods stack up against each other. A higher metabolizable energy number means a more nutrient-dense food, which can be a better value because the serving size is smaller.
You can't learn the quality of your dog's nutrients from the crude percentages, but reading the ingredients will give you some idea. A good quality dog food should list fat sources providing the right balance of omega-3 and omega-6 fatty acids. Fish, flaxseed and canola oil are typical sources of omega-3 fatty acids. Omega-6 fatty acids often come from pork and chicken fat as well as safflower, sunflower, corn and soybean oil. PetMD.com recommends avoiding ingredients such as lard and tallow, which are low-quality fats.