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

Is it okay to spray?

I am shortly getting a puppy which is a retriever breed and often used as a gundog. I was quite shocked to hear that many gundogs are trained using spray collars. Not only that, but many owners of this breed feel the need to use spray collars to get a good recall.
After all I have learned regarding behaviour, I don't think I'd feel comfortable using one with my dog. Are these collars really necessary and are they frequently used?
Tony Cruse, by email