It's a food supplement you can but at the local feed store.
http://www.petvetdirect.com/home.asp?cid=151
Here is what is says:
In nature, animals consume foods that are whole, raw and fresh, while domestic animals generally have a diet of processed foods only. The Missing Link was developed to target the nutritional gap between what nature provides and what is available in commercial foods. Formulated with all natural, human-edible-quality whole foods and food concentrates, The Missing Link reintroduces unprocessed, nutrient-rich foods into your animal's diet.
For years, veterinarians and pet owners have added The Missing Link Equine Formula to commercial foods to promote:
General Health & Well-Being
Better Digestion
Healthy Skin & Coat
Increased Energy
Quicker Recovery After Surgery or Injury
Less Shedding
Reduced Allergies
Less Scratching & Itching
Reduced Odor
Less Joint Stiffness and Pain
Spit 'n Shine Coat
Increased Stamina & Performance
Enhanced Hoof Strength
Less Dry and Splitting Hooves
Less Inflammation of Muscles, Joints & Tendons
Less Sand Colic & Respiratory Distress
Reduces Onset of Laminitis
Ingredients:
Ground Whole Flax Seed, Blackstrap Molasses, Rice Bran, Primary Dried Yeast, Dehydrated Alfalfa, Dried Carrot, Ground Hulled Sunflower Seed, Dried Apple, Sprouted Green Barley, Dried Kelp, Lecithin, Garlic and Yucca Schidigera Extract.