I have a 11-month old newfy male called TED, adorable in so many ways and very bright BUT very stubborn and testing me (I think??) for alpha status. I've just purchased the SitStayFetch program of training tools and am just downloading all the PDFs ready to learn as much as possible but is there anyone out there with a newfoundland (or similar) who might have some words of wisdom when coping with such a large breed? Ted is already hitting the 60kg mark and he's not even one yet !! In fact, I'd love to hear from anyone with a large breed dog - please get in touch!
I feel for you as we have three dogs, two of which are large breed (St. Bernard & Bloodhound). You did not specify what behaviors Ted is displaying that make you think he is challenging you, but Newfies are a smart, even tempered breed and he should respond well to consistant training.
Many people make the initial mistake of treating their pet like a human by letting them on furniture, leaving their food bowl accessable, allowing them in bed etc. These small, seemingly harmless actions send out very mixed messages to our pets and lead them to begin thinking that they are the Alpha. I think you should begin by reading the bonus "secrets to becoming the Alpha", as this will get you going in the right direction as far as establishing yourself (and all houshold members) as the pack leader.
In addition, the SitStayFetch program includes basic obedience training instruction, which you should begin immediately. Believe me, I waited until Ruby, my St. Bernard, was almost one year before beginning serious training and I really regret it!
Don't get frustrated if it takes a few tries to get Ted to respond to new commands and training....be consistant, rewarding and patient! Feel free to post some more specific examples of Ted's actions.