2021 was the year of the ox according to the Chinese calendar. The Chinese believe that if you dog is lacking "essence" you should feed it liver.
Liver is a funny ingredient. Although very nutritious - it is a source of vitamin A which is good for lots of things, including eyesight - if you give your dog too much it can do some unholy things to their digestion. I once gave Enid too much liver. Never again.
Fortunately, levels of liver here are at the appropriate amount of 5%. 
Dog Meats Bone rating using the All About Dog Food ratings calculator
Ingredients: 50% Ox, 20% Ox Hearts, 10% Turkey, 10% Turkey Bone, 5% Ox Liver, 5% Other Ox Offal
Analytical Declarations: Fat 24.6%, Moisture 56.9%, Ash 2.3%, Fibre 2.6%, Protein 15.4%
Size: 1kg