Cavalier King Charles male barking at Lorrys and cars.

[Gfplux]

Our daughter who lives with us has a Cavalier three years old.
I take him for walks a few times a week and over the last few months has started barking and lunging at vehicles.
This all started with large noisy digger type trucks, then lorrys and now includes most cars.
His actions are disturbing and also dangerous as he could slip the lead with a lunge.
He is a very docile dog under other circumstances, friendly, almost too friendly. Has never barked or been threatening in any way.
The dog is still a full dog and my daughter is considering chemical or actual castration! as a possible answer.
If a truck is spotted he can be distracted but it is so continues a walk near a road becomes unpleasant.
We live in a Town with lots of greenery but with lots of roads.
What should we do.
Thank you.

I should have added he has a medium sized garden to play in.

She needs to see a well qualified behaviourist - one APBC or CCAB accredited (the accreditation is important; lists are on APBC and ASAB websites) as it sounds like the dog has become reactive.

They're not cheap (though some insurance policies cover it), but for us in very very similar circumstances (basically the same, just different vehicles) and one session with an APBC behaviourist and three months of diligently following her instructions have massively paid off - we can walk down a street fairly reliably, with careful management techniques and a lot of squeeze liver pate.

Neutering will not work, and there's a good chance it will make things worse. These behaviours tend to be anxiety based, and such dogs need the confidence they get from the testosterone. A vasectomy is a good alternative for population control reasons, and chemical castration can be a good temporary measure to see the effects before committing. Either way, speak to a behaviourist first.

Finally, you mention the risk of him slipping the collar. I'd switch to a well fitted harness - I have a Perfect Fit for my dog and I would recommend it.

Our dog did this and we received good advice from a behaviourist. The first was to get an easy-fit harness. This has a D ring low down on the chest and another between the shoulders. It is used with a double end lead. Although the dog can jump she cannot lunges forwards. This has made a huge difference.

The second was to get the dog to respond to a clicker. So we cut down on her food and did clicker training at home in a safe environment,
the dog soon learnt that the clicker meant some kibble. We then bought a pouch with a clicker attached and put the kibble in it,

On the walks the dog learns to look at you for the kibble rather than the traffic, it took about 4 weeks for her to be fully confident. After two weeks, as soon as she heard the traffic she would look for the kibble rather than lunge. The first week I did click, kibble, praise and after a week she no longer needed the clicker. I would just say, what’s this or clicked my tongue. I feed her from my hand, but if she is a little dog you can throw it on the floor.

When we first had her, we could not go near a main road, she lunged at everything, including dogs and people. Now she is really confident and only rarely reacts to traffic. Hope this helps

It sounds like this is a fear response from one bad fright. If so neutering will definitely not improve this and would be very likely to make it worse.

It's also a difficult situation to stop since from his point of view it's a very successful behaviour - scary truck comes at him, he barks and lunges at it and so scary truck runs away from him thus in his mind, his barking made it leave him alone.

I would also suggest a fully qualified behaviourist (not a trainer) - 1 session would probably be it all it would take.