Collagen Beef Spring 9" Dog Chews. Collagen is known to help promote mobility and flexibility, help relieve joint pain and stiffness, and support skin, coat and digestive health. Collagen chews are made from the inner layer skin, often referred to as the “corium.” This layer of skin is extremely elastic. Unlike the epidermis (the layer used to make rawhide), corium contains a lot of collagen. Ingredients * Beef Collagen, Beef, Vegetable Glycerin. Caloric Content * 3000 kcal/kg, 150 kcal/treat Guaranteed Analysis Crude Protein 75.0% min Crude Fat 0.25% min Crude Fiber 1.0% max Moisture 20.0% max