Dogs usually cover their food because they're uncomfortable or insecure about eating it in that certain area. In most cases, they do like the food; it isn't a matter of the type or quality of it. Also, if the dog is being fed at the same time that the family is having dinner, the dog may be frightened because of all the noise. You can either relocate the dogs' food and water bowl, or choose to feed it at a different time.
A dog might cover its food because it is being fed too much. If it doesn't want to eat all the food at once, it might cover some to save it for later. Also, the dog might be covering the food to hide it from another dog in the family.