I believe this was on the discovery Channel some time ago.
This may be a Marsh deer that feeds near wet land marshes in South America, and the Annaconda along with other snakes prey upon them.

I never saw one dive head first ... slow and grisly death.

I have an uncle who had a brother-in-law who owned a burmese(?) python(14.5 ft)(Now in the Little Rock Zoo), and I got to "help" feed it once. A large rabbit. So yes I have. As for the deer, maybe a "roe" deer,bush buck(doe), or maybe one of the others listed above. +1's for you guy's "guesses".

Get ready all you southern folks, I hear Florida is full of them and with warm climate they will move East West and North. Glad I live in Michigan, the economy stinks but no nasty venomous critters or 20" long snakes.

just one bite and the snake is full for a year. thats amazing

Cool vid.

I've come across dead snakes that bit off more than they could [evidently] chew.

Shane is more than likely the first correct respondent. SE Asia is home to the Axis Deer, which this is not due to the lack of spots, the Sambar Deer, which females look alot like our whitetail, and thus is the most likely victim, and the extremely rare munjak, in which both male and female have antlers which are not visible on this deer.
Since the sambar can weigh upwards of 600 pounds(male) I 'm guessing this is a fawn sambar.

In a high school ecology class, we had a 16 foot albino Burmese python. It outgrew its jumbo rats (bred to be as large as a cottontail) and we were upgrading it to jumbo rabbits (like a big fat snowshoe in size). Apparently, they feed by scent, and this new rabbit didn't smell like the dinner it was used to. So here's this giant aloof snake, and here's this poor rabbit, trembling in the corner having a freakin' heart attack. The snake wouldn't eat it. So after a few hourse, we get the idea to make it smell good for the snake. We took some other smaller rats that were for the young reticulated pythons, and rubbed them on the rabbit. I guess it worked and the rabbit smelled like dinner now. About a minute later, the snake perked up and slammed it. Problem solved.

I would have to say a Florida Whitetail... hell we are already getting non native snakes breeding in our wetlands... but in reality, I would have to say a marsh deer in South America.

I don't know what kind of deer it was but unfortunately we have some pretty large pythons of our own living in Florida. I believe there was an article in Field and Stream or Outdoor Life about the python problem in Florida just a week or so ago. Who knows, a python could nail a whitetail fawn in Florida. A news story a day or so ago had a two year old child being killed by a python in Florida. The python got out of its terrarium and was found wrapped around the baby. Too bad for the child that the parents weren't more vigilant. A friend of mine had a boa in a terrarium and it was really spooky whenever you were in the room with it because it would follow by moving its head whenever you were in the room. It wasn't big enough to eat anyone my size but it still was kind of disconcerting to watch it watching you.