There is little agreement about whether supplements are necessary with a raw dog food diet. Purists point out that everything a dog needs for optimum nutrition as nature intended is provided by meat, bones and organs. Others hold that supplements are critical for addressing particular health concerns, whether one feeds raw or kibble. Most people take a conservative approach and feed a few common supplements.
There is no universal raw food diet model. Many people feed ground commercial raw products. Some of these also contain raw ground vegetables and supplements like kelp, flax seeds and fish oil. Others prefer to feed "whole prey" or a close approximation of such: poultry, rabbit, pork, beef, goat, fish and other meats, given to the dog in meal-sized pieces of meat and bone. It is also not uncommon for people to feed both some ground product alternating with whole meat and bone meals.
Broadly speaking, people who feed a raw food diet to their dogs fall into one of two camps--with perhaps the majority of people straddling both philosophies.
Tom Lonsdale, DVM, author of "Raw Meaty Bones," espouses a whole, natural diet, without ground raw, supplements or vegetables. Ian Billinghurst, DVM, author of "Give Your Dog a Bone," advocates a broader approach to feeding. He coined the phrase BARF (Bones and Raw Food) and recommends vegetables, fruits, table scraps and supplements in a meat-based diet.
Lonsdale maintains that "supplementary, synthetic vitamins" can do harm, and that the vitamins and minerals in raw, fresh food are all a dog needs. On the other hand, Billinghurst recommends supplementing with several vitamins, such as antioxidants like Vitamin C and Vitamin E, B-complex vitamins and other micro-nutrients like kelp and omega-3 fatty acids.
Legions of other veterinarians and experts in canine nutrition have weighed in on this debate, but there is little agreement on whether supplements are needed in a raw food diet, and if so, which supplements and what dosage.
Many people--whether they feed a raw food diet, a cooked diet or kibble--supplement with omega-3 fatty acids. Meat is already high in omega-6 fatty acids and some believe omega-3 is lacking. These are typically available in supplement form as either fish oil capsules or flaxseed supplements. Fish oil is the better choice: it is more bio-available to dogs. Research strongly suggests that omega-3 fatty acids are important for skin and coat health, joint function and even as "brain food" to grow intelligent puppies.
Some studies indicate that raw diets may be lacking in iodine. Adding kelp to the diet provides iodine, which is important in maintaining proper thyroid functioning. Iodine in the form of salt is added to most dry dog foods
Antioxidants and B-complex vitamins are supplied with alfalfa supplements or individual pills.
Supplementing for Specific Conditions
From arthritis to allergies, a huge range of supplements and nutraceuticals may be helpful (see link in Resources). Glucosamine and chondroitin are often recommended by veterinarians for arthritis and joint pain. Fish oil can be useful for soothing itchy skin and atopic allergies.
For specific conditions, do some on-line research and consider consulting with a veterinarian who practices complementary medicine or has training in canine nutrition.
When choosing supplements for a raw-fed dog, avoid those containing minerals. A raw food diet including bones is mineral-rich, and you can easily end up over-supplementing with calcium.
Do not be tempted to "cover all bases" by adding too many supplements to any diet, raw or otherwise. Some supplements do no harm in excess, but others can lead to serious health problems.
In short, you do not need to use supplements for a raw food diet (many do not), but some may be useful.