Dogs require different feeding schedules at different times of their lives. In addition, the size of a dog, her activity level or her stage of adulthood may have an effect on how often she should eat.
Puppies should eat frequently on a set, regular schedule between weaning and 6 months of age. Ideally, they should eat three times each day. Puppies over the age of 6 months can eat less frequently, although they should still be fed at least twice each day. According to the ASPCA, small breed puppies can be free fed; that is, they can have their food left out at all times. Very small puppies may experience hypoglycemia if they do not eat frequently, but it may be best to leave free feeding until their bodily functions have been regulated to make housetraining or housebreaking easier. The organization recommends that puppies who will have a normal, healthy weight over 20 pounds at maturity be fed using a portion controlled method several times each day.
The average medium-sized to large adult dog only needs to eat once a day, although many pet owners still prefer to feed them more frequently than that. According to the University of Missouri Extension, small breed adult dogs may do better if you feed them twice each day.
The quantity of food given to active dogs is not determined by frequency, but by the number of calories they need. You can determine the minimum calorie requirements for any dog between 5 and 99 pounds (2 to 45 kg) by multiplying the body weight in kilograms by 30 and adding 70. Using this formula, a 5 kg dog would have to take in 220 calories each day in order to meet his energy needs while at rest. However, active dogs need to take in anywhere from twice that amount to eight times that amount in order to maintain a normal body weight. Depending on what kind of food you give your dog, the quantity of food needed to meet those energy needs might dictate two or more meals each day.
Pregnant and Nursing Dogs
Neither pregnant nor nursing dogs should be fed any less often than recommended for their size. That is, feed large breed females twice a day to avoid bloat and to provide adequate nutrition. However, as the puppies grow inside of her, a pregnant dog may need to be fed more frequently to ensure that she takes in the amount of food and nutrients that she requires. A nursing female will continue to require more frequent feedings in order to support her nutritional needs, as well as those of the puppies. The American Kennel Club recommends that nursing females be supplied with food at all times, but if you prefer portion feeding for any reason, feed your nursing dog at least three times a day.
Like any other dogs, senior dogs prefer a regular daily routine. No set feeding schedule is recommended for a senior dog. What is important is that your senior dog gets the nutrition that she requires. It is possible that her appetite will not be as good as it once was, so smaller, more frequent meals might be suitable. You should let her physical needs dictate what you do, rather than attempt to impose your schedule on her.