Is all dry food the same?

I was having an conversation with someone at work the other day about dog food and they said that there are more than one type of dry food, and I said it was all the same - just different brand names. Can you settle the argument, it's just dry or wet surely!
Kevin Lynch, Newbury, Berks

I have to break it to you - I can think of four different types of dry food at least! Extruded, baked, cold pressed and freeze dried. There may be even more! Can anyone think of any more?
Beverley Cuddy, Editor

… and that just relates to the texture of the dried food. More important for your dog’s health is the formulation. That refers not only to the quality of the ingredients but also to the proportions in which they appear in the food.
Dog food has come a long way since the days when you simply bought dog food for your dog, or perhaps cooked it from scratch. I well remember the smell of pet mince boiling on the stove – we bought it from the butcher, cooked it in a saucepan with a little water, and then poured it into aluminium tins. Once cool, an inch thick layer of white fat solidified on top.
When you go to buy dog food now, there is a very wide range of brands available, which in itself will vary between outlets. The initial decision is between wet and dried, or deciding to feed a combination of the two. There are essentially two broad categories of dog food: life stage or prescription. A life stage food is designed for the dog with no health issues, and addresses the needs of the healthy individual as he moves through life from puppy to young adult, active or inactive, entire or neutered, and in to senior years. It is also possible to find foods geared to meet the special needs of toy breeds and large breeds, and some ranges offer foods for specific breeds.
A prescription food is fed under veterinary supervision because the formulation addresses a specific health issue such as, for example, kidney disease, liver disease, obesity. As such, your dog’s health will dictate the need to feed a prescription diet. There are different ranges which address health issues in different ways through their individual formulations.
Above all, however, there is one factor which decides which food a dog will eat – palatability. We have different tastes from each other, and dogs are not much different. Some are fussier than others. I am lucky in that my Labradors will eat anything put in their bowls (and anything else they find outside their bowls, whatever its state of decay!). A food may have great health attributes, but it will be of no help if it is not eaten. One dried food may look very much like another, but they do taste differently, as any owner of a fussy dog will attest!
Alison Logan, Vet