leash reactive and recall problems

[Nell Cunliffe]

I have a 4 year old Rottweiler who i adopted 7 months ago.  He is really well behaved and highly trained but very leash reactive to other dogs so I can’t let him off his leash because even though his recall is excellent under normal circumstances if he sees another dog he bolts away like I don’t exist.  I have been treat training and praising and it works if we are far enough away I just don’t know how to progress this to allow him to run around leash free or socialise without fear of him not coming back when called or starting a fight as he is so big he would get me into trouble.  He is an angel but sounds like a monster sometimes when walking past another dog.  Any advice would be greatly appreciated 😊

[Adrienne]

Hello and welcome to the forums,

Congrats on having your Rottie highly trained, it is always a pleasure to see well-trained Rottweilers, this breed needs it! 

In regards to his behavior, I would like to have more information. 

Based on his past behavior (please don't try to let him off leash purposely to provide me with an answer), when he sees another dog and bolts away ignoring you, what happens next? Does he actually go greet the dog? Or do things look rather tense? Has he ever started a fight? Has the place you have adopted him from 7 months ago provided any info or history of how he does with other dogs?

I am asking this to differentiate possible barrier frustration from true "reactivity." Dogs with barrier frustration do fine and are even friendly with other dogs when off leash, but struggle when they are on leash or behind a barrier because such barriers frustrate them as it prevents them from meeting and playing with other dogs. Hence, why this type of behavior is referred to as "barrier frustration." 

Based on my experience though, with Rotties (especially those over the age of 2-3 years old) I tend to see more *true* reactivity- the type where the dog reacts more as a distance-increasing behavior (the dog desires distance/dislikes other dogs) rather than a distance-decreasing one (the dog desires meeting the dog/likes dogs). 

There is quite a large gap between going from barking, growling at other dogs on walks to having our dogs socializing/mingling with other dogs to the point where we can feel comfortable and safe having them off leash (unless it's truly barrier frustration) as the risks at stake are too high. We can find though some middle grounds where we can attain a better level of control over their behaviors on walks. I can provide some guidance on that. 

 

[Nell Cunliffe]

Hi 🙋‍♀️ and thank you!  
he was trained as a personal protector and guard dog previous to me rehoming him, he was raised and trained in kennels which sell personal protection dogs, he was returned at 3 due to owners ill health and rehomed to me as retired and a family dog.  I was told he was great around other dogs and has proven to be fine when playing under supervision - when another owner I met in the park with 5 dogs convinced me to let him off and play.  However when on leash walking past another dog he can become very dominant acting- snarling and going into a full barking growling fit.  He has never started a fight but I have never given him the opportunity and keep him on the leash unless I am certain no one else will be around.   I have treat trained him so we can walk past quite near but I still keep a distance when possible.  It took quite a while but he is now very good with that and can hold his focus on me and let the dog pass unless it starts barking at him which frequently happens. He can walk past and ignore if I hold up something tasty unless the other dog barks first then he loses his head and goes wild.  He will allow friendly dogs to come up to him and sniff but after about 5 seconds or if I try to pull him away he launches to attack mode.  Sometimes he snarles and tries to mount them.  He also gets extremely distracted and will dart off into the distance if he sees something that takes his attention.  He has no trouble with recall if NOT distracted and does not get distracted by people.  He is great with puppies and female dogs, it’s just other males.  He loves to run and his face lights up when he is allowed to be free but I just can’t allow it as I just am not 100% certain how he would react with other males off the lead and don’t know how I could ever find out giving the circumstances I feel like I’m letting him down 😞 I hired a dog trainer but he is not helping at all.  Sometimes it’s just so tiering worrying if we will walk into another leashed dog in a narrow path in the park it makes me feel quite anxious at times as he is very strong and very loud!!  I don’t believe he has been used to being on lead at all times before I adopted him but do believe he was trained quite harshly.  He does have a very dominant personality and have been advised to get him neutered on numerous occasions but I really want to avoid this.

we have been playing all the games on the site working through them and I can honestly say although it’s not helping with the problem I am desperately trying for it is creating a much deeper bond between us and I think I am enjoying it as much as him! He does seem to be looking to me more as leader lately and so I am trying to build this as much as possible positively but it’s so hard when I have no experience- he is my first dog I definitely jumped in at the deep end but never regret it he is a joy to have with us so I really want to help him act calmly around other dogs.  He is such a loving boy with so much energy and I would love to just let him run.

thank you for any help and advice you are able to provide in advance I am so grateful!

 

thank you

Nell

[Adrienne]

Thank you for the extra details, they are very helpful!

Hopefully those kennels specializing in personal protection/guard dogs were ran by very experienced people, I am always suspicious about what methods they use. There is a very, very thin line between getting a dog who is constantly suspicious of everyone and one blessed with a super stable temperament, confidence and the uncanny ability to discern friend from foe. In any case, he sounds like he turned out to be a lovely boy who is just in need of guidance. 

In general with Rotties, they tend to be friendly with other dogs as puppies and youngsters, but as they mature things tend to change somewhat and some may unfortunately no longer be tolerant of other dogs. This is even mentioned in their breed standard. The American Kennel Club standard for the Rottweiler breed describes Rottweilers as being  "calm, confident and courageous dogs with a self-assured aloofness that does not lend itself to immediate and indiscriminate friendships. Their "attitude" towards other dogs is also alluded to where it states: "An aggressive or belligerent attitude towards other dogs should not be faulted." 

Often, to be more precise, we see changes in behaviors towards other dogs once they reach social maturity, which in this breed takes place at 2 to 3 years of age. During this time, Rottweilers may turn out being more selective over what dogs they wish to befriend. The may therefore start restricting their circle of friends and some may come to no longer tolerate certain dogs/interactions. In general, if a Rottie gets along with a few specific type of dogs, organizing play dates with these specific dogs will be much safer than going to a dog park with different dogs. 

Several Rottweilers also during this time start no longer tolerating "rude" behaviors from other dogs. They may growl when a young Labrador gets in their face, they may snarl if a dog dares placing a leg on their shoulder or chin, they may no longer appreciate meeting and greeting other dogs on walks, especially if these encounters last longer than they would like (like 3 seconds max!) Some may attempt to place their chin on other dogs' shoulders or mount which can be a trigger for fights if the other dog objects. 

With my own Rotties, my neutered male (Einstein) remained over all fine with other dogs for most of his life , although he wouldn't hesitate to correct with a growl if a dog engaged in rude behaviors. He made a good teacher dog. The worst thing that happened was one day a dog was trying to attack him over some food I had, and he must have felt this dog was endangering me or what not, so he quickly pinned this dog to ground, and held him down holding him by the neck.  I told him to detach, and when he did, I was afraid to find a bloody mess needing stitches, instead all I found was wet fur, soaked with his saliva no teeth marks of scratches. Thankfully he had great bite inhibition and apparently didn't want to truly harm this dog!

With my female, things were more problematic. She went through a phase where she would lunge and bark at dogs on walks around the age of 2. We worked on this by doing several trips to the city and feeding high-value treats (baked liver) every time a dog crossed our path.  However,  although I gained great control this way, when I kept her off leash with a group of dogs, she wanted to be in control, playing the role of the "fun police." In other words, any dogs who were playing rough aroused her and she would get a really intense look on her face and try to intervene to stop them. With well mannered dogs, she did just fine, but with the rude ones or dogs who provoked her, she would flip. It's as if she wanted to have the last word: "What did you just say?" I was able to work on this to a good extent, yet  I never trusted her 100 percent around hyper dogs so carefully screened the dogs she could be exposed to which were usually the best behaved ones. 

Here's the thing: when Rottweilers are provided with guidance, they can often be successfully persuaded from acting out their instincts. Now this doesn't mean you'll need to force your Rottweiler to accept things he doesn't like from other dogs, it just means, you'll have to prevent putting him certain situations, while aiming to change his underlying emotional state and train him alternative behaviors you'll like him engage in instead of going into attack mode. 

This is a breed of dog that will do anything you want him to, but if you give him full reign of certain situations, he'll do everything you allow him to do. Certainly, training your Rottweiler to ignore other dogs isn't the easiest task, but with patience, consistency and hopefully guidance from the right professional, you can potentially make progress (although nobody can ever make guarantees on the outcome). 

It goes without saying that every dog is different. I have known some Rotties who did perfectly fine with other dogs, some not too much, and some who would kill them given the opportunity. Rottweilers, just like people, are similar to snowflakes, meaning they all come with their individual personalities. Even among puppies of the same litter, there maybe lots of differences, so it all boils down to personality traits that can be part inherited, part learned.

From your description over all, it  sounds like Rottweiler mostly struggles with males. This is not surprising. Firstly, he's intact and many neutered male dogs tend to act defensively towards intact males because they give off a specific smell, so he may be picking up on this. On top of this, same-sex aggression is not at all uncommon in this breed. 

It sounds like you have never had the opportunity to expose him to male dogs off leash, but the risks as stake may be too high for now. Generally, to play it safe, I recommend off-leash adventures only to highly-trained dogs under excellent voice control and with non-aggressive tendencies. Being off leash is a privilege and it should be warranted only when the dog has proven himself to not get into trouble when there are people or other dogs around. Ideally, a dog trained to be walked off leash should be not interested in meeting other dogs and would rather stick to the owner's side. It takes lots of practice and a strong bond to reach this level of training. On top of this, we need to consider that being intact, any possible female dogs in heat in the area may act as a major distraction. 

Compromising with a Long Line 

 

For dogs who haven't reached that almost perfect level of voice control, but whose owners wish to have them have a bit more freedom on walks to sniff around, explore and be a dog, I suggest for safety to have the dog walk on a long line, (never while texting or talking on the phone!) while always carefully scanning for approaching people and dogs. A long line should not be confused for a retractable leash, which is something I don't recommend using.

A long-line is a long, light rope or cord that may range anywhere between 10 and 50 feet long. You can often find these in horse and tack stores as the one for horses may also work well for dogs, but nowadays more and more companies are crafting long lines specifically for canines especially for tracking purposes. Generally, I start with the shorter ones and increase length as the dog proves himself worthy of more impulse control.

When using a long line, you will always need to be scanning for triggers ahead so that you can quickly reel your dog in closer to you for better control.  I like to wear gloves to protect my skin from rope burn, but it's nice to see that lately some companies are making some in leather which are much more gentle on the hands. However, the rope ones offer the advantage that you can tie knots every few feet that you can use to gain traction and hold on to have a better grip in case your dog takes off running. You will also have to keep a close eye that the line doesn't get wrapped between your legs or your dog's legs. Ideally, the line should stay to your dog’s side so to not interfere with movement.

Unlike a retractable leash, a long line encourages engagement with your dog and provides you with a "life line" for emergency situations. A long-line as well can help in modifying a dog's behavior because it prevents him from rehearsing troublesome behaviors that may lead to a bite one day. Yes, he might still growl at a distance but at least him and the other dogs walking by are safer.

Now, if you are taking him to an area where other off leash dogs approach him, I would avoid those as these encounters could deeply interfere with your training. I can't emphasize this enough: I don't know how many dogs' training are ruined each year by negative encounters. I can tell you that there are stories of nicely trained service dogs who becomes fearful of other dogs because of an encounter gone wrong with an off-leash dog.

When on a long line, I always prefer to have dog owners train a cue that tells the dog to come closer rather than reeling the dog in. You can read on how to train a strong recall using a long line here:

https://www.braintraining4dogs.com/members/brain-training/obedience-101/recall/

This because equipment should not be a substitute for training. Equipment is more like a "crutch". We also want to have good voice control in the case something unexpected happens (he bolts out your door, a collar comes off, the dog breaks through a fence). The long line again can be  also used to your advantage in obtaining a "feel" on his level of training.

Tips/Ideas for Walks

It sounds like your biggest struggle on walks is passing by another dog.  Here are a few tips in regards to his behavior on walks:

-Provide more exercise and mental stimulation (brain games!). Rottweilers, especially when young and under the age of 5, are very energetic dogs. I hear that you have already been doing several brain games. Although this doesn't help directly with your issue, it accomplishes many things at deeper level.  Exercise and mental stimulation helps tire dogs out and when their pent-up energy is diffused, they take training better and tolerate things more easily. It also provides outlets for instinctive behaviors.

- I would suggest also training better impulse control and frustration tolerance:

 https://www.braintraining4dogs.com/members/archive/impulse-control-frustration-tolerance/

-Keep distance from other dogs on walks, at least initially. Being too close to other dogs will make your Rottweiler react with more intensity and you won't be able to ask him to engage in an alternate behavior. Work on keeping your Rottweiler under threshold by constantly scanning your environment, looking out for other dogs. Here is how to monitor threshold levels:

https://www.braintraining4dogs.com/members/archive/threshold-levels/

-Create positive associations with dogs. The Look at that method can turn helpful. You can start this exercise indoors by having him watch other dogs passing by your home before progressing to walks.  Make sure to use super-high value treats. Here is a guide:

https://www.braintraining4dogs.com/members/brain-training/university/look-at-that/

-At home, you can also try to desensitize him to the sound of barking dogs (using a recording first) using the "hear that" method. Both look at that and hear that are based on behavior modification techniques using desensitization and counterconditioning. 

https://www.braintraining4dogs.com/members/archive/pre-lat-look-behavior-modification/

-Train your dog an emergency u-turn. This will turn helpful if you ever cross another dog in your path that's too close for comfort. Here's how: 

 https://www.braintraining4dogs.com/members/archive/emergency-u-turn/

-Invest in a front-attachment harness (where the leash attaches to a front ring by the dog's chest) or a head halter (this requires a conditioning period) for better control on walks. Rottweilers are very strong and we may feel nervous if we can't keep them under control. Our nervousness can then travel all the way down the leash and your dog may therefore pick up on your emotions.  

-Train your dog to do several steps of attention heeling. This can come handy to distract him when passing dogs. 

https://www.braintraining4dogs.com/members/brain-training/obedience-101/heeling-attention-heeling/

-Have a plan in place if an off-leash dog approaches your dog. For instance, you toss this dog a few treats to gain some distance as you do an emergency u-turn. If you're too late and he's already nose-to-nose with your Rottweiler, you can try to happy talk and encourage your Rottweiler to move on with you without pulling (see next tip). 

-You can actually pre-train some helpful behaviors to rely on in such above circumstances. This is advanced training once you have a good level of control around other dogs at closer distances. For instance, you can train your dog to go behind you when there's another dog approaching or you can train him some cue such as "that'll do" where he detaches from the encounter and follows you without the need to pull him away (which brings to the next tip). 

-Careful on that leash pull when your Rottie is meeting another dog.  Many dog trainers suggest to try to keep the leash loose (easier said than done as our brains are flashing danger warnings all about) since tight leashes tend to amp dogs up. This video has been popular among dog training circles to show the effect pulling a dog away may have on the dog. Watch it in slow motion. Youtube under settings allows you to control the playback speed. I like to put it on 0.25 when watching dog interactions. 

https://www.youtube.com/watch?v=WxS27ieAiLI

-Keep things brief. If not matter what, your dog happens to meet other dogs on walks, try to keep it under 3 seconds. Give your dog a cue to detach from the interaction. Longer interactions are often the ones that stir trouble. Several dogs don't like to be sniffed too long.

-I don't know what methods your current trainer is using. I hope they are force-free. If he or she has a good, rather bomb-proof teacher dog, it would help doing several set-ups with this dog, working on distance work. Ideally though, it would be best enlisting the help of a dog behavior consultant such as a board-certified veterinary behaviorist (DACVB) or a Certified Applied Animal Behaviorist (CAAB) for safety and correct implementation of behavior modification. These are the big experts in the field. Reactivity/dog aggression/fear/ frustration/anxiety fall under behavior modification more than training. The goal is to change the dog's emotional response initially though desensitization and counterconditioning. Once we attain this, it is much easier to train them to respond to our cues. 

Overall by providing more exercise and mental stimulation, teaching better impulse control, preventing your Rottie from rehearsing problem behaviors (taking off, trying to mount, snarling), creating positive associations with barking/seeing dogs from a distance, training alternate behaviors and having a back-up plan in case of a close encounter, we may start to see a steadily yet gradual reduction in the problem behavior. 

I hope this helps. 

Let me know if you have any questions!

Best,

Adrienne 

Disclaimer: behavior modification comes with risks. If your dog shows signs of potential aggression (lunging, barking, growling, snapping) for safety, please consult with a dog behavior professional who uses force-free behavior modification techniques for direct in-person guidance. 

 

[Nell Cunliffe]

Thank you so much for all of this advice.  Yes what you mentioned at top sounds a lot like him in being very selective.  Some dogs he just tends not to like and others he can happily ignore.  There are a lot of off leash dogs who display rude behaviour to him unfortunately and when we create a distance their owners don’t attempt to call them away which is extremely frustrating.  He is generally fine like you say for 3-5 seconds haha.  He is fine up to quite a close distance too but I find it easier to just try avoid them altogether.  I just don’t want to be doing the wrong thing by keeping him from another dogs completely and make the situation worse.   I have been using two strong leads attached to each other when the coast is clear because since we played the find it game his nose has found a new lease of life and loves to snuffle in the long grass haha.  Perhaps for now I’ll let him indulge in this new hobby more this seems to completely distract him even from other dogs at the moment and get a long line for this.  I will re read all your tips and hopefully   In time he will mellow with the training.  Thank you for your help it is so much more than anyone has ever given before.  
 

[Adrienne]

You are very welcome!

I hear you about the dogs who engage in rude behaviors. We have dealt with this issue many times and had to decide to frequent different areas just to avoid the problems. Occasionally, such encounters still occurred every now and then (like dogs escaping their properties) and tossing them treats to detour them often helped.  I also carried "Spray Shield' with me just in case of aggressive encounters. 

If he is selective and you know there are some dogs he certainly gets well along with, with no particular problems whatsoever, I would suggest sticking to socializing with them. This should be enough for now to upkeep his social skills while also ensuring things stay positive and happy.  

We often think that play should be the way dogs mingle with other dogs, but walking with other dogs can also be productive (and put less stress on us worrying about things happening when dogs mingle off leash). If you have friends with dogs your Rottie does fine with, organizing some group walks/hikes (once the COVID19 situation is better under control) can also be a form of socialization, a more structured form giving a sense of "togetherness", but socialization nonetheless. 

For the sniffing, we can find a compromise on walks so that we both get to enjoy the perks that come along with all the stimuli associated with the great outdoors. Since dogs benefit from sniffing from time to time,(sniffing is a tiring activity too, win-win!) we can therefore work on putting it on cue.

Every now and then, when your dog is walking nicely by your side, walk towards an area that you'll be using for your dog's sniffing pleasure. Practice walking to this area on a loose leash. Make it a habit to say "go sniff" as you point to the area, so that your dog understands that you are giving him permission to go on a sniffing adventure. This is  one of the easiest training cues you will ever train as most dogs know what to do when you let them approach a "pee-mail" area.

Make sure you give him a bit time and when he seems to be losing interest,  say “let’s go!” praise, and continue on your walk. Or even better, if you have access to a fenced area where your dog can safely stay off leash and sniff to his heart's content, walk towards this area, and when that leash is dangling in a nice slack "U," snap off the leash and say "go sniff." Most dogs at some point get tired of sniffing, so once the novelty is gone, this is a good time to call your dog and reward him.

Keep me posted!

I am always here if you have any questions,

Best,

Adrienne 

[Nell Cunliffe]

Thank you your help is so much appreciated he is such a lovely dog but noticed he will constantly test me so can’t drop my slack with him haha.  Yes sniffing seems to be his thing at the moment he gets lost in another world it’s quite amusing to watch!  There are a lot of dogs everywhere we go so have planned out quieter routes to and from the places we go and take the off track routes which are actually nicer.  We have a huge bond and I think because of the lockdowns this year we literally don’t spend any time apart and it’s usually just the two of us he is like my best friend but have noticed lately he is getting a little more overprotective towards me and anyone who enters the house.  He used to be fine with this, excited even but he has now started to growl to the point I have to lock him in another room.  He is less tolerant of strangers petting him also when out and about and let’s off a low throat grumble.  I am a bit concerned is this something I should be worried about? And how do I make him feel relaxed at people he doesn’t know coming into the house?  I don’t want this to become a problem 😬 thank you so much

[Adrienne]

You are very welcome.

It is so great that you have such a strong bond. Many dog owners are reporting increases in their bonds with their dogs with all the lockdowns going on which is great, although the downside is that some dogs come to develop separation anxiety once it's time for dog owners to go back to work. It certainly helps to get dogs gradually accustomed to their new schedules ahead of time. 

Because Rottweilers have been historically bred to be livestock herders during the day and livestock guardians at night, they still retain protective, territorial instincts. However, they shouldn't threaten or attack your guests. 

Does he also display this behavior when people approach the home? Like does he bark a lot looking out of windows or behind the fence when he sees people? Or the mailman? Or is it more when they enter the door?

Can you describe more in details the behavior of him being overprotective towards you? In what circumstances does it happen? 

Is the throat grumble when strangers pet him also a new thing?

It sounds like these are some recent behaviors. If so how, how long ago did they start? Did he change a lot or was he already giving signs of not liking people petting him?

I know you say he was excited before when guests would come, but sometimes that excitement is actually triggered by underlying anxiety and can be a precursor to not feeling comfortable around them.  

Can you track down any reason for his behavior changes? Any recent changes? Any new stress? Has he seen the vet recently?

These extra details can be helpful.

Thanks

 

[Nell Cunliffe]

Thanks, yes it’s very recent behaviour.  Both for the petting and the people he doesn’t know entering the house.  He doesn’t bark or make a fuss if someone knocks at the door and has always been generally fine with people entering the house but just in the past few weeks he has become a little bit territorial if someone tries to enter he just stays very still and makes the rumble sound as if to say back out now.  If someone is out at the front and I need to answer the door for example he will go in away from the door when I tell him and he doesn’t make a fuss but will peer out of the window to see who it is.  It’s only when they enter he becomes wary.  There are certain people he has become to dislike where he was fine before, ie the mailman used to pet him and the neighbour but he doesn’t approve of them anymore all of a sudden and I have to tell them they shouldn’t come near him.  Strangers are hit and miss he was always much more of a mans dog but he seems to be a bit wary of them lately.  He doesn’t like anyone hugging either, he doesn’t growl if I hug with someone but he barks frantically as though he is confused at what he should be doing.  I have been trying to reassure him it’s ok by holding my hand out to him to pet him which seems to calm him.  Is there a specific way I should handle this behaviour it’s ever so slight and only a warning never has he been aggressive but the last thing I would ever want is it to progress into aggression! 

[Adrienne]

Thanks for the extra details, very helpful thanks!

With recent behaviors, that sort of start out of the blue like that, a first step would be ensuring there are no underlying medical problems going on. Rottweilers are particularly prone to hypothyroidism which can cause behavior changes. Any type of pain/physical discomfort can do that too so a thorough veterinary examination would be a good starting point.

Once all the possible underlying medical medical stuff are ruled out and the issue is therefore found to stem from something behavioral ,rather than medical, you can then start considering behavior modification. 

In the meanwhile, management would be important. While we would love to have Rotties willing to be pet and hugged by people we have to consider a Rottweiler's " self-assured aloofness that does not lend itself to immediate and indiscriminate friendships." You will therefore need to step in and let others know that your Rottie doesn't like to be pet and hugged from now on. You would also have to monitor your Rottweiler carefully for signs of stress when around people to make sure he isn't uncomfortable so to avoid putting him in situations that may be put him over threshold.

My female Rottweiler loved to be pet and given any form of attention, while my male would sort of accept it, or better let's say tolerate it, but I wouldn't allow people to give him a hug. Hugging is more of a primate thing us humans do and not all dogs are accepting of it, especially from strangers. Many dogs tend to perceive it as an invasion of space and a person putting their face so close to theirs is risky. 

On one occasion, a child with an intellectual disability at an open-event came from nowhere and went straight to hugging Einstein tightly in a headlock-fashion placing his face so close to his.  I literally saw his eyes almost popping out. Alarm bells started ringing in my head, but I was happy I had treats so I just fed several to him in a row until the child dislodged and he appeared fine with that. Phewww...

Thankfully, your Rottweiler is "using his words" by grumbling, but a warning is a warning and therefore we need to be very careful as a bite can come next. Studies have shown that bending over a dog, putting the face close to the dog's face and making eye contact (all behaviors taking place in combination when hugging or kissing a dog), these behaviors often led to bites directed towards the central area of the face. I know many dog owners claim that their dogs seem to really enjoy being hugged, but is that the real picture? In some cases, dogs may be showing very subtle signs of discomfort that go unnoticed.

 Sure, snarling, growling and snapping are pretty obvious signs that are quite easy to understand, however, according to a study, low-intensity warning signals of discomfort such as yawning, nose licking, turning the head and showing "whale eyes" are often not recognized, even by adult care takers. If we look at random pictures of dogs being hugged we'll often notice the dog's body language is far from happy. If we watch a video of a person hugging a dog in slow motion, we can capture many stress signals. 

Here are signs of stress in dogs:

https://www.braintraining4dogs.com/members/archive/signs-fear-stress-dogs/

See Kendal Shepherd's Ladder of Aggression illustration here: 

https://www.braintraining4dogs.com/members/archive/dogs-dont-bite-blue/

Scolding a dog for growling is counterproductive although it's often our instinctive reaction. Here's a read about why we never want to suppress growling:

https://www.braintraining4dogs.com/members/archive/growling-never-suppressed-dogs/

We don't want to ignore the behavior either because growling is a dog's plead for help. The dog is asking for distance and is saying he's not comfortable. It's important to take a note of it and work on it using management (preventing exposing him to situations where he feels uncomfortable) and behavior modification (working on changing the dog's emotional response often through desensitization and counterconditioning), sometimes combined with some training (often teaching alternate, incompatible behaviors for the dog to engage in to replace the problematic behaviors). 

For behavior modification, it would be important enlisting the help of a dog behavior professional. This is for your safety and the safety of those around you and for correct implementation of behavior modification.  In your situation, a board-certified veterinary behaviorist (DACVB) may work best considering that these experts are veterinarians specializing in behavior and therefore they can do a full medical workup to exclude any insidious medical issues, and then, if nothing comes up, behavior modification can be started.  

I know you say that he is only issuing a warning and he has never been aggressive, but a snap or bite is right around the corner if we don't tackle the underlying root cause.  This breed is big and powerful, and owning a Rottweiler is a big privilege, but also a big responsibility. On top of caring for our Rotties, we need to ensure our dogs don't pose any risks to others and we also need to protect the breed from the issue of breed-specific legislations and negative stereotyping. Even if though our dogs aren't actively biting, their growling/grumbling is more like saying : "I am not comfortable with this, please don't make me bite you."

If you are in the mood for some reading, this thread discusses hugging dogs, dogs reacting towards people hugging and dogs reactive towards men etc.

As always, safety is paramount. A disclaimer is warranted here since we are dealing with several forms of aggression: caution is always needed when dealing with cases of aggression. Behavior modification comes with risks and therefore it's important to seek out the assistance of a dog behavior professional for safety and correct implementation. Muzzle training may be needed if there are risks for bites and a management plan is always advisable while awaiting the aid of professional.