The presence of some or all of the ingredients which are the most commonly used dog food ingredients, or an assortment of these ingredients, does not necessarily mean that your dog is going to be well nourished. The ingredients must be in the right combinations and of good quality, both before and after processing.
Let’s get started with the Biological Value (BV). The BV’s of the ingredients are a key to good nutrition. The biological value of a food is the measurement of the amino acid completeness of the proteins contained by the food.
BV is a scale of measurement used to determine what percentage of a given nutrient source is utilized by the body. The scale is most frequently applied to protein sources, particularly whey protein. BV is derived from providing a measure intake of protein, then determining the nitrogen uptake versus nitrogen excretion. The theoretical highest BV of any food source is 100%. In short, BV refers to how well and how quickly your body can actually use the protein you consume.
Eggs for example are considered a great source of protein because they contain all of the essential amino acids. Here are some more biological value figures:
Eggs (whole) 100, eggs (whites) 88, chicken/turkey 79, fish 70, lean beef 69, cow's milk 60, unpolished rice 59, brown rice 57, white rice 56, peas 55, whole wheat 49, soy beans 47, whole grain wheat 44, peanuts 43, corn 36, dry beans 34, white potato 34.
Neither wheat nor corn would be an adequate diet alone, but fed together with one or two meat based proteins capable of supplying the missing amino acids, they could supply an adequate diet.
Nutrition is the sum of processes involved in taking in nutrients and assimilating and utilizing them. Nutrients are fat, protein, carbohydrates, vitamins, minerals, and water necessary for the growth, normal functioning and maintaining of life. The two main issues here are palatability and digestibility. Ingredients are only as important as the nutrients they contain, how good they taste to the pet, and their digestibility. Picture a big truck having to go through a tunnel to drop off a load of produce. The ingredients symbolize your truck, the nutrients your truck’s load. If the truck is trying to drive into the tunnel, but it won't fit (i.e. food is not digestible), it's not going to be able to drop off its load. This would be a poor ingredient to put into a food. If the truck goes through the tunnel, but only has lettuce in the bed when it could also have additionally fit valuable tomatoes and potatoes, then the load is not an efficient one. This would be an example of how one pet food manages nutrients within one ingredient (truck). If the truck isn't allowed into the tunnel because the person at the toll booth does not authorize the drive, then it's all in vain. The truck could carry the best produce in the world, but it can't deliver. This is an example of a dog or cat rejecting the food (palatability).
Digestibility refers to the quantity of the food that is actually absorbed by the dog's system. These numbers usually can be obtained by contacting the manufacturer directly. If your manufacturer does not provide this information (Red flag to begin with) you can calculate it yourself. Here is how: Weigh the amount of food that you feed and the weight of the stool for several days. Divide the weight of the food into the weight of the stool and the result is the percentage of digestibility. It is important to note, that the stool that you are going to use must be dried to the same moisture content as the food you feed if you want to be close. You will also need a little more math than just add, subtract, divide and multiply if you want to be close to an accurate answer. (Let’s just hope that we can get the appropriate figures from the manufacturer, agreed?) The more food is fully metabolized, the higher is the digestibility figure.
Quality Before Processing: Understanding the definition of an ingredient is not enough. Many grains grown in poor soil will lack needed vitamins and minerals, an unfortunate common occurrence. Grains and vegetables can be polluted with fertilizer residues and pesticides of various kinds.
Ingredients can also be soiled with mold, mildew, and fungus. The quality of meat can be suspect. We have all heard stories or had personal experiences of finding bits of hair and other unsavory additives in our hamburger, but the quality of meats used for dog foods is much lower. According to the U.S. Department of Agriculture (USDA), federal inspection of ingredients used in pet food manufacturing is non mandatory.
However, some states do inspect manufacturing plants, especially those producing canned pet foods. In the majority of states it is legal and common practice for pet food manufactures to use what are known as "4-D" meat sources, animals that are dead, dying, diseased, or disabled when they arrive at the slaughterhouse. Dr. P. F. McGargle, a Veterinarian and a former federal meat inspector, believes that feeding slaughterhouse wastes to pet animals increases their chances of getting cancer and other degenerative diseases. He claims, "Those wastes include moldy, rancid or spoiled processed meats, as well as tissues too severely riddled with cancer to be eaten by people."
Pet food labels provide seemingly a lot of information. Learning how to use this information will require some time. This certainly cannot and should not be done at the pet food market in front of the food aisle. Be prepared, study the labels at home so that you can look at them more thoroughly. Many food manufacturers provide to stores and vets food samples. These are yours for the asking. If you get a variety of samples from different companies, you can then study those labels at home, at your leisure.
As you study, keep in mind that there is also a lot of information not disclosed on the label, such as for example the above mentioned criteria like ingredient quality, biological nutrient values, palatability and digestibility figures. This kind information can be difficult to come by and you may need to rely upon the recommendation of experts, including reps at the pet food store or your vet. You also should consider the price, quality, and reputation of the manufacturer.