I walk my 7 month old pup twice a day, an hour in the morning and between 40 mins to an hour in the afternoon. She also gets longer and more varied walks where possible when I'm off work.
On our morning walk, I meet up with two other ladies with 5 dogs between them. Afternoons, we walk with our older dog who is 14. In the mornings, our pup playfights with one of the other, younger dogs... they have done for the last 4 months, they love each other and it's gentle, but with some growly sound effects. It has never given me any cause for concern.
When pup meets other dogs, she always does a bark and then goes to them and submits. If the dog accepts her, then she will instigate play. Over the last week however, I have noticed her hackles rising more during this process.
Today we met another dog who looked a similar age. They played but my pup seemed over dominant so I called her and she came. The other pup followed, ignoring her owner's calls. Eventually she went back. On the way back from our walk, we met the same dogs again. One spaniel that barked constantly and the pup that mine had played with. They started to play and once again, my pup became more dominant, pinning the other pup down. Then it all turned really nasty and mine went for the other pup's throat. I stepped in to grab my dog and at the same time, the other lady ran over shouting "Please get your dog off". As I grabbed mine, the lady kicked her. I pulled my dog away and said " I'm so sorry, she has never, ever done anything like this before". I wanted to check how hwr dog was but she pulled her away and shouted "You need to control your dog!". I understood that she was upset.... so was I, my dog had attacked hers. I had tried to explain that I couldn't have pre-empted the attack, as my pup had never behaved in that way before. In frustration, I repeated "I said she has never, ever done that before", but the lady walked away, clearly upset and angry. I really wanted to check her dog was alright but she was so angry and I felt so shaken that I felt following her wouldn't have been productive.
I phoned the two local vets to see if the lady had been in.... she hadn't so I'm guessing there was no injury. I've left my number just in case. I've also got the name of a behaviourist from our vet.
I feel horrible tonight. Our pup clearly understood that I was cross with her. She slunk into her crate when we got home and stayed there for most of the evening. I love her to bits... she's a pain sometimes but she's never shown aggression like that before.... I'm scared to take her out tomorrow 
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