You wouldn't think something as simple as a dog collar would be a hotly contested subject, but a simple scan of some online discussions shows just how contentious it can be - and how confusing, as well. To help pet owners navigate this, I'm going to explore a few different types of training collars and give you my opinion on the pros and cons of each of them. No training collar is the perfect fit for all kinds of dogs, all kinds of situations, and every pet owner, but with a little guidance you can make the right choice for your pet. (Note: for this article, I'll just focus on training collars, not dog harnesses.)
Training collars are usually used either to train a dog to walk on a leash with ease, or to teach property boundaries or stop barking.
No collar, regardless of type, is going to completely solve all your training problems by itself: success takes work, commitment and perseverance. Sometimes working with a good trainer or veterinary behaviorist will help solve more difficult behavior problems.
Electronic/static collars: These collars can help your dog learn the boundaries of your property (if used with an in-ground, wireless system) or help them decrease an unwanted activity like barking. For keeping your dog safe and confined, the in-ground wire transmits a signal which makes the collar emit a training tone, which gets your dog's attention. If they proceed outside the zone of protection, it delivers a static correction - not enough to cause pain, but enough to get their attention and respect the boundary. Over few days, they learn that the tone means "no correction" and stay inside the perimeter. The same principle applies to barking - if the activity continues, a distracting correction is given which will abolish the activity over time. This is the kind of collar I have used on my dogs, both for learning the boundaries of the property and to stop barking.
Pros: Convenient, very effective at eliminating unwanted activity and containment in areas where fences are impossible or unwanted. Once the dog learns to respect the warning tone, no correction is given.
Cons: More expense than everyday collars, require training to be used effectively. Must be charged or have batteries changed periodically. If left on too long, contact points can cause neck irritation.
Pinch or prong collars: These collars have blunt metal prongs that will press on a dog's neck if excess force is applied, as when a dog pulls on the leash. They don't really pinch, so that name is not really appropriate. These are best suited for dogs who strain at the leash or a hard to control. Like many training collars, these should not be left on for days on end, since there is a risk of skin irritation from constant contact with the collar. Also, dogs with any sort of tracheal (windpipe) problems should not use these collars, as they can make these conditions worse.
Pros: Easy to use, inexpensive. Cons: Effectiveness depends on the dog's ability to learn from the relatively mild correction. Some dogs will still pull despite the prongs and may need a more effective solution like a static collar. No effect on barking.
Citronella collars: These collars work in a similar fashion to the static collars, where they detect an unwanted activity (usually barking) and instead of a static correction, deliver a spray of harmless citronella near the dog's nose to distract him and decrease the activity. I have tried one of these on my own dog and, while it did help decrease the barking, I had to switch to a static correction collar to get it to stop completely. Pros: Often seen as more acceptable than static correction collars. Effective for dogs that respond to the surprising spray. Cons: Sometimes don't respond to high-pitched barks, some dogs don't respond to the burst of citronella. Requires refills of spray and maintaining battery.
Choke/slip collars: While the name can be a bit off-putting, slip or choke collars can be an effective aid if used carefully. Like the prong collar, these exert pressure on the dog's neck that increases as the dog pulls. The difference here is that, while a prong collar has an endpoint of pressure, a choke collar can continually tighten the more a dog pulls, which can lead to a potentially unsafe or even deadly situation if the dog becomes stuck or trapped. These collars should only be used when on a walk for training and should not be used as an everyday type of collar. Pros: Can be effective for dogs who pull, inexpensive and convenient. Less chance of skin irritation than a prong collar. Cons: Safety concerns as above. No effect on barking.
Head/halter-type collars: Not technically a collar, these are more similar to a halter worn by a horse, in that they wrap around the bridge of the nose and control head movement. For dogs that have tracheal problems, like small dogs that have tracheal collapse, these may be preferred to a collar that puts pressure on the neck. They can help train a dog to not pull on a leash and make for a more controlled walking experience. Pros: Least chance of tracheal irritation or damage, effective and controlling dogs who pull. Inexpensive and convenient. Cons: Can be confusing to place correctly on the dog's head. May not be effective for strong or strong-willed dogs. Not usable on snub-nosed dogs like pugs or bulldogs. No effect on barking.