American cocker spaniel behaviour advice needed?

[Emily2195]

Hello,

I have an 8 year old American cocker spaniel male named Ollie, of whom I've had since he was 8 weeks old. He was well socialised, and trained from the beginning and we've had no problems. However, in the last year his behaviour has changed. (He was castrated about 17 months ago) He air snaps at some other dogs when he's out with me, he will growl and then air snap close to them. Ive asked my parents and family friends who look after him if he does it with them, and they all insist that he doesn't.
When he's on the lead, he will purposely avoid other dogs and then want to sniff their behinds as they walk away. Off lead, he's fine with some dogs (usually smaller dogs/same size dogs), but with bouncy or larger dogs, will air snap at them. I avoid other dogs as best as i can, but he used to be such a sociable dog and I think but avoiding other dogs, I'm not actually addressing the problem.

At home, when friends bring round their dogs that he's known for years, he has never air snapped or growled at them, but also doesn't really interact with them anymore.

Any help would be greatly appreciated.
Thank you.

[Nettle]

Any sudden change in behaviour needs a full veterinary check, because most often the dog is feeling vulnerable because s/he is unwell. It could be something simple and easily fixed or it could be a lifetime medication thing - what is most important is to find out what it is and have a full list of options and alternatives from your vet. It is particularly important for him to have his prostate checked, and among the blood tests a full thyroid panel, which you will have to ask for as it isn't done routinely. Check out Dr. Jean Donaldson for how low thyroid affects behaviour. You need to have his sight and hearing checked, joints and skeleton, teeth, everything.

Castration in any case lowers confidence and makes some dogs feel vulnerable. Is there a pattern to the dogs he air-snaps at? Obviously they have all come too close, and it's your job to stop that, but have they been threatening him by staring or getting in his face?

First part of the job on your side IS to keep other dogs he doesn't know away from him. This isn't pointless - it is very important. Right now he needs to be able to trust you to keep him safe. He is a better judge of another dog's intentions than any human.

Once he knows that you will manage matters, he will be more relaxed about other dogs.