Do you turn into an animal when someone injects animal blood into your bloodstream?

No, because it is not your blood, or your blood type (unless it is another person with the same blood type) and so your body will naturally reject it. Also, your body isn't a fool, and si it won't change your entire identity in something a simple as that! Even if the person/animal has the same blood type as your blood and it accepts it, you don't change into that person or animal, your body changes the DNA in the blood to make it your own, plus, just a little injection of blood won't change ALL of the rest of your blood! But, be careful, you could get horrible diseases from it, like HIV, AIDS, or others like that, which may kill you!