The 3 categories of dog food are:

• Dried
• Semi-moist
• Moist

Dry pellet dog food, called kibble, is made in two different ways: extruding and baking.  During extruding, a mixture of raw materials is fed into an expander while pressurized steam or hot water is added.  When removed from the pressure, the pellets puff like popcorn.  The pellets are allowed to dry, then sprayed with vitamins, grease, or any other ingredients that are not heat tolerant.  The down side of extruding is that the fats added after cooking often turn rancid and the vitamins may be destroyed during storage or shopping.

Dog treats are usually higher in fat content.  These are usually designed to be held in a person's hand without being too messy, and are often designed in fanciful shapes and colours.

Some examples of dog food products

Brands of dog food