I am no expert, but that looked like a pretty old dog. I might not be the smartest girl on the street, but if that deer had been doing that to any dog - mine or someone else's I wouldn't be standing on the porch screaming. I ffel awful for the dog.
The thing I love are the people that think deer, elk, moose, and others are cute nice friendly animals! I am just glad it was a dog (not to sound evil) and not a person or worse ..... a Kid! Hope people see this and realize there are differences between wildlife and petting zoos even if they are the same animal.
Just goes to show you, NEVER F with a mother when her young are close. I guess they do not have leash laws where this was taped. And if they did and the owner followed it, there dog would be safe at home.