I knew a couple with Pyr and they said the breed is known for running off to explore. Big escape artists. I don’t know if that’s accurate for all of them, but I know it caused them great headaches.
I’ve had a few giant breeds. A Mastiff, a Dogue de Bordeaux and I’ve worked with an Irish wolfhound, a Newfoundland and a few others like the Tibetan mastiff. Forget about aggression. That’s more to do with the owner and the dog’s upbringing. No breed is aggressive. The Malinois has high energy, intelligence and drive, and will be hard work.
I personally loved the Mastiff the most. He was a big protective teddy bear. So calm, but very aware. I’ve never had a dog like him. He really was the best, and easiest dog I’ve ever had. He didn’t need much exercise to be happy and was no bother at all in the house.
The Newfoundland was lovely, but the shedding was absolutely horrendous. And they really are happiest with water. The wolfhound will have the typical sighthound attributes like a penchant for chasing things. They would certainly be a more suitable jogging companion though. Drooling/slobber wasn’t a major issue for me with any of these breeds. The worst one I’ve had for that was a St. Bernard/Labrador cross.
I’ve got a mastiff. I got him because my wide wanted a dog she could cuddle with. He’s tiny for a mastiff at only 180 lbs but to everyone in my apartment complex he’s massive. He was really easy to train and we spent his first 2 years doing the obedience thing so my wife would still be in charge when he got huge. They say no dog is easier to train with the down command and boy is that true, we use it over sit most of the time because he just drops and relaxes and it makes people feel more comfortable with him.
All that being said we’ve talked about it and we probably wouldn’t get another one. The drool is hard we spend an hour cleaning our walls every weekend and the arms of our couches are gross and need to be cleaned again. We keep drool rags around the house to minimize the problem but getting guest not to freak out when he comes over slobbering and wanting love is tough. Even our family doesn’t really want to dog sit on occasion because of the drool. Ours is also intact, due to our breeder thinking he was the pick and us trying to turn him into a show dog, and he’s a bit dominant with other dogs but nothing more then I’ve seen from other intact males. The last thing is we have a brindle and if you think regular mastiffs look intimidating you should see the brindles, even people that know he’s a love freak out when he barks or moves quickly and of course that means that going to the dog park is more difficult.
If you’ve got any other questions let me know.
If you’re going to be using the dog as a therapy animal for other folks, particularly those who have experienced trauma, I would caution against an excessively large dog. I would also caution against a dog with an extreme drool/shedding problem, as people could end up having an allergic reaction- definitely not what you’re going for.
How about a Portuguese Water Dog or a Standard Poodle? I’ve worked with both as service animals, and they’re rock solid. Standards are a great size, are extremely intelligent and easy to train, and less likely to be an allergen issue.
ETA: Standards are wonderful running partners. The giant breeds, particularly the wolfhound, shouldn’t be run until they’re full grown.
My daughters have a black Goldendoodle (half Standard Poodle, half Golden Retriever) that looks exactly like this one. She is a big girl on her way to 90+ pounds, very smart and protective. She loves everyone but you wouldn’t know it by the way she confronts any strangers that approach the house or the girls. They are “designer dogs” that have few longevity and health issues.
The most impressive large dog that I have ever known was a Great Dane - Rottweiler cross. He was basically a Rottweiler the size of a Great Dane named Onyx. If you don’t think that is intimidating, you never met him. He was as sweet as pie and owned by the transvestite handyman that lived in the attic of the hotel we worked at in New Orleans. I used to babysit Onyx but he got so much attention and was so big and strong that he was hard to control. He had a primal, deep bark like thunder. We kept him on a leash at all times but, if he wanted to go somewhere or greet someone, you WERE going with him because you didn’t have a choice. The cute thing was that his transvestite owner got him matching dresses and huge spiked leather collars. They were always quite the attraction walking down St. Charles Avenue.
The only dogs I have ever seen that were as intimidating as Onyx are Tibetan Mastiffs. They are expensive and hard to find but I can guarantee nobody is gong to mess with you if you have one.
How about an Anatolian Shepherd?
They are great with people and socialize well. Not a huge amount of energy, but they do love exercise. 2-3 walks a day and ours is happy.
Ours has been very trainable and will do anything you want for a treat. Awesome with cats, as long as you get the dog young.
Overall very trainable but independent minded.
My friend has a giant brindle mastiff, he’s a big ol’ like o’ love.
Maybe I missed this in your posts, but why not consider a really large black lab? My guy was 100 lbs and a great watch dog barker (but extremely people friendly and trustworthy). The “English” labs are stockier than the American strain.
I love Labs, I do, and the current Service puppy I am raising (his birthday is today) is around 98lbs of drooly love. He is a Lab/Bernese Mountain cross, but looks like a big, jowly Lab. He is amazing.
I don’t want another one right away because it sounds silly, but this one was just exceptional. I want a fresh start.
Not a huge fan of poodles - just don’t like the look of them. Labradoodles are hit and miss, since they are a designer, you have no guarantees.
I knew about the running thing - it actually applies to any large dog - but good tip and important to remember.
The size is actually a bit of the opposite effect, tends to be comforting, at least in my experience, but we will have a little dog for victim-survivors that prefer a lap dog.
Just a note, from a Dane dad, that dog poop is proportional to two things: the size of the dog and, to quite an extent, the quality of the food. Dogs fed stuff with a lot of grain filler, especially corn, will have massive dumps because the filler isn’t digested. My Danes poop about the same size as Goldens, etc. Not small, but not the mountains most might imagine (or see).
I agree whole-heartedly. The puppy I currently have is sponsored by Purina, so his poops right now are HUGE. When I have had similar dogs on Orjen or Taste of the Wild, poops are much smaller. 
I have a Newfie. If you are looking for a dog to work with trauma victims, I think the breed is an excellent choice. You’ll need to do some work to find the right dog.
Positives - majestic, calm, lovable and loving. Unflappable. Very, very low key. I’ve had 40 second graders climb all over him and he stood rock steady and loved every second.
Negatives - very, very low key. I call mine “the bear rug” for a reason. This is not really a working breed. I wanted mine for water rescue and his interest in training is possibly lower than my cats, despite working with a reputable breeder to get a puppy that should have been more interested in working. He loves me. He loves all people. He just couldn’t care less about working.
I think you could easily find a Newfie who did fit all of your boxes and would be completely awesome. He stops crowds everywhere (not kidding) and attracts kids and strangers like a walking stuffed animal. Just make sure you’re choosing from a working line (I think my mistake was a show line), and that you’re clear on what your end goals are.
Happy to discuss Newfies at length if you have more questions.
I would love to discuss more - should I PM you?
Can I PM you about Mastiffs?
Sure or we can talk in thread, either is good.
Firstly, the brindle is lovely :). Now, the drool. I understand excessive, I do. I am thinking floors are preferable to carpet, wipe-off furniture instead of microfiber, and possibly a patterned duvet cover on the bed he/she will most likely sleep on?
Our current service puppy is around 1/2 - 1/3 the weight of the Mastiff (he is around 98 lbs) and because of his cross with the Bernese Mountain, we already have the lakes of drool, especially after he drinks (we call it “re-wetting his licker” since he doesn’t seem to actually get much of the water into his system). My uniform is very handy, since drool doesn’t show on the Digitalized Camo :).
My main concern with the Newfie is the coat/grooming (it is no doubt intense, how often are you fully brushing and what do you recommend) and I worry about keeping it cool in the summer. Although I have no doubt the dog will LOVE winter, I worry about he/she overheating - valid concern?
We adopted a retired wheel-chair service dog who was a Giant Schnauzer. She was a really good dog. GSs are nothing like the little yappy Mini ones (neither are the Standards, for that matter). They are very stately and generally quiet dogs. If they have not been raised with cats, it can be really difficult to introduce an adult to cats (it took us several months), but it’s possible; however, I would recommend socializing a puppy around cats.
I met a GS puppy that was about 4 months old once, and about the size of a Mini. It was not as crazy and yappy as an adult Mini.
Ours lived to be 11, which is pretty long for a dog that weighed 120lbs. They are prone to bladder problems, and in her last two years, she had three major ones. One time we had to come up with $60 for a strong antibiotic, although it stopped the cycle. Part of the problem, and this is kind of gross, but it’s got to do with the fur growing around their genitals trapping bacteria. Once we were clued into that by someone at the dog park with a Briard, it helped a lot.
We didn’t always professionally groom her. We used to experiment with cuts for fun. We had the “buffalo cut,” and the “wolf cut.”
She had cropped ears, but she came that way, and they were different sizes-- bad crop job. Probably not done by a vet. She also had a docked tail. If you get a puppy, and can avoid cropping the ears, that would be my recommendation. You may not have a choice in the tail dock. We always left enough fur on her ears when she was clipped to hide the bad crop.
She was really well-trained. Since she was retired, we had to teach her that it was OK to play, to get on the couch like the other dogs, and such. She never would get on the bed.
Other than the need for grooming, GSs are pretty good dogs. They don’t seem to suffer much from separation anxiety, because they were originally a herding breed.
If I needed a giant breed for something, I would definitely consider a GS, although I would want a young one, because I would want to know how it was socialized. I wouldn’t want to go through training an adult to accept cats again. And I would never crop. If I could avoid docking, I’d do that too.
Just hoping Sunny Daze, and oredigger77 may see this and answer. If not, I will PM 
I’m a life-long lover of most giant dog breeds. During college, I worked as a dog bather and familiarized myself with most dog breeds, with the giants always being among my favs, and we’ve had Newfoundlands since I was a kid.
What would be most helpful in advising you is to know what other kinds of attributes you’re looking for (and which are a turn-off). In particular, I’d be interested in what you’d prefer with respect to overall energy level, how much time and money you’re able to devote to grooming needs, what the climate is like in your area, and what your living situation is (e.g., if you live in an apartment, have access to a large yard, how many stairs the dog will need to traverse, etc).
I second everything Sunny Daze has said about Newfies, and will add my own two cents. Firstly, as far as getting a dog that’s non-aggressive, Newfoundlands certainly fit that bill. They’re perfectly suited for what you were describing in your follow-up post about wanting a service dog for PTSD support. I’m finishing my Ph.D in clinical psychology, and once I’m done with internship, I plan on training our next Newfie to do something similar to what you described.
The same temperament that makes them so well-suited for therapy work can be a downside on the protection front, which you also mention. They really love people (in a calm, less demonstrative kind of way than some other dogs) and are not at all wary of strangers. Additionally, they tend to be on the more laid back (or downright lazy) side and are not going to go on ‘high alert’ if someone walks down the sidewalk outside your home, at least not during the day; ours have always let us know when someone was on the property that at night. In fact, ours once altered us to an early-morning break-in happening next door.
Personally, I’ve always found this aspect of their temperament to be a plus, as I don’t want my dog to start barking uncontrollably every time the UPS driver leaves a box on the stoop. Even without the barking and ‘high alert’ attitude, though, Newfies can be a pretty powerful crime deterrent nevertheless… One day, a kid from the high school football team went around raising money for new uniforms or some such. I saw him come up the driveway, and was waiting for the doorbell to ring. A few seconds later, I saw him running full-tilt back down the driveway again, at which point he got back in his car and sped off. Perplexed, I went outside to try and figure out what happened…and there was our Newfie, stretched out on the porch. He’d slept through the entire encounter. At any rate, it really depends on what exactly you’re looking for as far as the ‘protection’ factor goes.
Yes, drool can be a problem, though not always horribly so (and that’s going to be true of many of the giant breeds). Worse than the drool, though, are the grooming requirements. Newfies have very dense coats and require brushing at least weekly or they will start to mat and can develop hot spots. The grooming can be extremely time consuming to maintain oneself (especially if you let it go for a while), and can be expensive if you have a groomer/bather do the bulk of the work for you. Shaving is not recommended unless the dog is really old or their coat is in horrible condition, as the fur is useful in making sure the dog doesn’t get sunburned and because the coat can grow in weirdly after it’s been shaved. Needless to say, they’re also not the most heat-tolerant dogs. I’ve lived with mine in Ohio and Michigan, and they tend to sleep a lot more often in the summer months (often directly on top of the air conditioning vent) and aren’t interested in exercising unless it’s at night or involves complete submersion in water.
English Mastiffs are similar in many ways to Newfies as far as the guard-dog and temperament issues go. The grooming requirements are certainly less, but they do shed a good bit, and if you’ve got a particularly wrinkly one it’s necessary to clean out the facial wrinkles regularly or they can get smelly or even infected. They’re also not great in the heat.
I’m not an expert on Irish Wolfhounds, though I’ve been around many…in my experience, they’ve been a little bit more aloof and willful than Newfies, and much more energetic (though this may have been more about the personality of their owners than a trait that’s truly inherent to the breed).
There have been many good suggestions about other breeds you might want to consider already. I’d second looking into Great Danes, Great Pyrennes, Cane Corsos, Neapolitan Mastiffs, and St. Bernards, and would also recommend Leonbergers and Bernese Mountain Dogs (I don’t think I saw those mentioned upthread).