A few thoughts on our four legged friends...
1) Seems those who have never had a serious attack understate the risks (what's the big deal) verses those who have had incidents (like me) who warn bikers to be very wary of dogs.
2) Make sure you report a dog bite, especially a vicious animal, as they may eventually get a child in the area. The authorities will also cite the owners if the dog does not have shots or tags.
3) As was the case with me I fell defending myself. After being bitten I kicked the dog hard twice, which stopped the attack, but hit a curb behind be and was thrown to the street, adding road rash to my injuries.
4) Animal attacks can be very fast and with little or no warning. Backwoodsmen have learned to carry bear spray on a waist holster at all times, and even then have barely had time to use it. Having complicated defense devices, especially if they are buried in your packs or concealed (like firearms) may not help until it is too late.
5) The dog that attacked me was not playful, it was a vicious out-for-blood attack which I had to forcibly stop.
6) Do not shoot deterent sprays into the wind, they will be blown back into your face.
7) Wear heavy shoes whenever possible to protect feet and to kick the dog.
8) Stay away from dogs, even if they are leashed. Do not assume the owners have any control over the animal.