This series of blogs looks at the scientific research into whether vegetarian and vegan dog food is healthy for your dog. This blog summaries at a scientific study published in 2009, in the British Journal of Nutrition by W. Y. Brown et al.
The paper is called “An experimental meat-free diet maintained hematological characteristics
in sprint-racing sled dogs”
A nutritionally complete vegetarian / vegan diet is fine for dogs, even very active dogs like racing huskies. The huskies fed a vegetarian diet had the same blood test results as those fed on a meat diet. They all the dogs did same amount of exercise. Vegetarian and meat based foods have similar ingredients.