The article that Carol2004 referred you to is an excellent article.
I make raw goat milk yogurt and because of the competing "good" bacteria in the goat milk, I need to gently heat the milk to 180 if I want a firmer yogurt. While most Americans prefer a firm yogurt, many people in other countries prefer the liquid state and thus end up drinking it.
While it is true that you destroy the good bacteria and enzymes if you heat the milk to 180, you add back good bacteria when you add your culture. I use Natren yogurt starter. If you choose to heat your raw milk to 110 you will be drinking it, but it is still great tasting and just as beneficial for your health.