Thanks for that additional information. It is helpful. Barking at other dogs can be your dogs way of trying to get their attention to play or be an aggressive behavior. Without seeing her, it is difficult to tell. I suspect it is a bit of aggression so let me approach that first.
Dogs are aggressive toward other dogs for a variety of reasons. It might be that they are fearful of other dogs and thus are aggressive before the other dog can be. In other cases, a dog is aggressive in order to dominate the other dogs and be the alpha member of the pack. Other causes could be that the dog feels they are the alpha member of the pack and as the alpha member they must protect the pack (you) from threats (other dogs). There are also dogs that are only aggressive on the lead and never off the lead. I'll go ahead and give a site that discusses leash reactivity.
In addition, owners sometimes make the situation even worse by tensing up and worrying about what will happen. The dog senses the owner worry and feels that he is justified in his aggressive stance because you are obviously worried about the dog. They don't know you are worried about them attacking, they just feel that you are worried and assume it is the other dog. It may have even started when you saw a large or aggressive dog approaching and she picked up on that. If so, you would not be the first or last person to respond like that.
The gact that she is not that off lead is a good indicator that you can correct this. The site I gave you has lots of good tips and you should try them.
Some addition things that you can try is to start back up the obedience training. You can do it at home. I'm going to give you a site that teaches you how to teach your dog and has advanced commands as well. Be sure and click on the link to the page on obedience at the bottom. and links on subsequent pages leading to detailed instructions.
Training works best if you train at least 30 minutes a day (two 15 minute sessions). I would start making your dog work via the Nothing in life is free program (NILF). It is outlined below.
Obedience training serves various purposes. It helps a dog learn what humans expect of them when they state a command which leads to self confidence and less fear. Each time a dog obeys a command, even if it is for a treat, it makes them a little more submissive to that human in the future which helps with dominance aggression. And since it is the leader or boss who is responsible for protecting the pack, if the dog is made submissive with training, you are responsible for protecting him, so that can reduce aggression due to fear and dominance.
You can also use the commands to control your dog's behavior as well by ordering them to sit or lay down and rewarding the obedience with the treat which takes her mind off the other dog. When she barks and you give a treat, she thinks your are rewarding the barking. So using treats has to be timed right to be effective.
Another option is to teach the dog the quiet command. As crazy as it seems, you may want to teach the speak command and then the quiet command. It seems easier to teach the quiet command after your dog has learned the speak command. The following site explains teaching speak and quiet commands.
If this doesn't work, you may have to try a citronella bark collar though this may have the same effect as the spray. Personally spraying her is not cruel and if it stops the behavior, she is getting an immediate reprimand for the undesired behavior which is fine. However, you need to couple that with rewarding her with a treat when she doesn't react. Get a helper who will walk their dog in the distance and when she does not bark with them at a distance, reward her. If she does, do a little squirt and have the other dog back away a little and repeat. As she stops barking at that distance, have them repeat at a closer distance until she stops barking all together.
Bat training may help as well. You can read about this here:
These things should help take care of the problem. I hope this information is helpful to you and you are satisfied with my response. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have .