NUTRITION LABELS - WHAT DO THEY REALLY TELL YOU?
After the post regarding concerns with copper levels in pet food, it became apparent to me that folks take the pet food label as "gospel", believing the food contains the exact levels of each ingredient listed on the label. This is a false belief.
The labels on pet food bags list the guaranteed "maximum" or "minimum" of each ingredient. One or two batches of finished product are tested to confirm that the minimum or maximum levels are in line with the label claims. Not every batch of food is tested. In fact, very few batches are tested. Testing is very expensive and can cost upwards of $2500 per food. Even with home cooking, everything is a "best guess" when calculating fat, protein, calories, and nutrient profile.
Let's say you want to feed a low fat diet. Turkey is lower in fat, generally, than beef. So you buy ground turkey. Ground turkey can have turkey skin, white meat, and dark meat included, which will raise the fat content. I looked up copper content of beef liver and found the following levels on charts for the same amount of liver: 14.5 mg, 21.5, 14.3, and 12.0. These numbers are pretty different.
Every batch of food that is processed will have different levels of nutrients, depending on the ingredients used to make the food. Was the beef grass fed or feedlot cattle? Was the fish wild caught or farmed? Was the product refrigerated, fresh, or frozen prior to processing the food? How depleted was the soil upon which the grains were grown? Unless the exact nutrient profile of every ingredient is tested and known, there can be significant variation between batches. And we will only know the exact nutrient profile of a food if it is tested after production. Even then, how much degradation takes place if the bag or can of food sits in a warehouse or store for a year before being eaten?
The bottom line is that we do the best we can with the information we have available for each individual pet. Splitting hairs and trying to make this into an exact science is nonproductive and pretty impossible.
