To spray or not to spray

I have a seven-year-old Cavalier who keeps barking whenever he goes into the garden because there is a horse on one side of the garden and cattle on the other side – both groups of animals often come up quite close and my Cav starts barking when he sees them.

I am thinking about using a spray collar or some sort of vibrating collar and would like some opinions on them and how effective they are. I don’t know what else to

do and do want to stop my neighbours complaining about the dog!

Maggie, Isle of Wight, by phone

Spray it again?

I went to a local dog training club recently with a relative and noticed a line of water sprayers on the trainer's desk. My relative's dog was getting stressed so I started blocking him from the source of anxiety. The trainer came over and told me that blocking wouldn't work and handed me a water spray! She told me to say 'no' and spray the dog's face. The dog was already stressed!
I looked around the room and saw a couple of other handlers using sprays. Whenever their dog barked they would say 'no' and spray. It was probably used as an interrupt rather that a punisher, but I just don't like the idea.
I know a lot of training clubs use them but can they work and what is the logic behind using them?
Tony Cruse, by email