Dog aggression has little to do with breed, …

…so test the owners….


By Dr. Rachel Casey

It is always heart-breaking when children are injured by family dogs, and tragic when it leads to a death. Emotions understandably run high and there are calls for “something to be done”. Often the focus is on the most obvious element, such as the breed of the dog involved.

Dog breed is commonly discussed in media reports of attacks and, despite the inaccuracies recent research shows these reports often contain, such discussion leads to perceptions that breed is a key factor in the risk of aggression. Is this the case, or is it distracting us from other important factors influencing dog behaviour? While there is little research in this area, what there is suggests the dog’s breed is of little importance.

Good dog, bad dogAggressive dog

At Bristol University, we surveyed dog owners regarding aggressive behaviour in their dogs, such as growling, lunging, barking and biting. We asked about the occurrence of aggressive behaviour in three situations; towards family members, towards unfamiliar people entering the house, and towards unfamiliar people outside the house. From the nearly 4,000 replies, we investigated whether dogs were reported to show aggressive behaviour in more than one situation, and whether the characteristics of owners (such as age) and their dogs (including breed) influenced the risk of aggression in each context.

What we found was that dogs tend not to be aggressive in more than one of the surveyed situations. That is, those that are aggressive towards family members rarely do so towards unfamiliar people, and vice versa. This is important, because it challenges the idea that dogs are either innately vicious, or “man’s best friend”.

This won’t be a great surprise to anyone familiar with dog behaviour, who will know that each dog with a tendency towards aggression will have a backstory, where the behaviour can be traced to a specific situation. But it’s a very important message for the general public: understanding that any dog can potentially be aggressive given the right circumstances is key to reducing injuries. Approaching an unfamiliar dog without checking with the owner first is not a good idea, even if it looks cute and friendly with others. And owners need to understand that even their gorgeous, loving pet can show aggression if exposed to a situation where it feels anxious or threatened enough.

Does that mean that all dogs should be controlled in some way, muzzled or kept away from children? No, of course not – dogs enhance our lives in so many ways, and most live alongside us without any problem. What’s more, keeping dogs away from people could be counter-productive: less familiarity with people is likely to make dogs more worried about them, increasing the risk of aggression. Better to focus on education, so people understand why aggression develops and can recognize early signs. This is particularly important for those getting puppies, whose early life can, like humans, have a big impact on the whole of their life. And these messages need to be simple, clear, authoritative and consistent.

Not in the breeding

In our study, we compared breed groups in each situation with a reference category of cross-breeds. In terms of dogs that were aggressive toward family members, we found no difference between those of specific breeds and cross-breeds. For aggression toward unfamiliar people, gundogs (hounds, retrievers and pointers) had a reduced risk compared to cross-breeds, and pastoral or herding dogs (for example German shepherd dogs) had an increased risk specifically when outside the house.


So there are some breed effects on risk of aggression in some circumstances, but, importantly, the contribution these effects made was small. No more than 10% of the difference between aggressive and non-aggressive dogs were accounted for by the statistical models – and these included all the significant factors, not just breed.

Clearly different breeds vary in aspects of their behaviour – any dog owner will tell you that. But when it comes to risk of aggression, the influence of breed is pretty small. It’s also important to point out that we don’t know if these effects are related to the characteristics of the dogs themselves, because they could also be influenced by the type of people who choose to own particular breed types. So, in evaluating aggression risk for an individual dog, there are more important factors to consider than its breed.

Ownership tests

But there is one aspect where breed is relevant to the risk of injury from dogs: size and strength. Because while large or powerful dogs don’t display any greater risk of aggression than any other, the potential for serious injury is higher if they do. So should particular, powerful breeds be banned? To answer that, it’s worth considering whether there’s evidence that this approach works, or whether reducing aggression risk in all dogs is a better approach.

Several countries, including the UK, have banned or restricted certain breeds. This had dealt a blow to dog welfare, not least those surreal cases where dogs’ lives are determined not by their behaviour but on measurements of leg length or skull width, and the long-term kennelling of dogs during protracted legal proceedings.

History seems to show that this approach is not effective at reducing injuries – in fact they are rising, despite these measures. Paradoxically, breed-specific legislation can increase the number of dogs of banned breeds, as the cachet of an outlawed dog appeals to some. Dogs in these environments can indeed become dangerous – because the way they are treated makes aggressive behaviour more likely.

Policy should instead focus on the factors that influence the risk of aggression in the first place. Most people object when governments take the approach of banning things – imagine the cries of “nanny state” if fast cars were banned from the roads on account of their greater likelihood of causing injury than less powerful vehicles if driven irresponsibly. In reality, society takes the approach of reducing the risk posed by all drivers, regardless of what car they drive.

Every new driver is given a thorough education, which is bench-marked by a standard theoretical and practical driving test. We have well-established, and largely accepted, codes of practice that govern drivers’ behaviour to reduce accident risk, and laws to enforce them. It would make sense to take the same approach for reducing aggression towards humans in dogs.


Reprinted with permission from THE CONVERSATION

Veterinary Regenerative Medicine

By Dr. David Lane, DVM

Regenerative medicine is a new branch of medicine that examines how the body heals itself, then looks for ways to concentrate those efforts where they are most needed.  Techniques are rapidly evolving as we learn more, but even though it is early days it is already showing great promise for many treating musculoskeletal conditions that we couldn’t before.


It is particularly useful for alleviating the pain of arthritis, and for growing new tendon or ligament tissue.


Below is a brief overview of the regenerative medicine options available for treating musculoskeletal issues in dogs.


Hyaluronic Acid Joint InjectionsBMA MSC collection


Hyaluronic acid (HA) is a key component of healthy joint fluid and cartilage, and is depleted in arthritic joints, which leads to worsening arthritis, which depletes HA – it’s a self-perpetuating cycle. There are effective oral and subcutaneous injection products that help boost HA levels, but direct injections into the joint are the most effective way to quickly replace HA levels.


HA can be used on its own for early or mild arthritis, or combined with steroids for more advanced and/or painful conditions.  It can also be combined with stem cells or PRP (see below). Although we frequently use HA injections for severely arthritic joints, the best effects are seen when it is given earlier in the disease process.


Although HA injections into the joint are helpful, especially when combined with steroids, the effects don’t last as long as they do with PRP injections.  There are different steroids that can be used, each with their own pro’s and con’s; the choice of which steroid to use should be matched to your dog’s individual needs.


PRP (platelet rich plasma)


Platelets are the body’s front line soldiers for repairing damaged tissue.  They clot the wound to stop bleeding, then release a number of growth factors to initiate the healing process.  By collecting a sample of blood from your dog, concentrating down the platelet fraction and then re-injecting this platelet rich plasma (PRP) where it is needed, we see a number of positive effects.


PRP accelerates healing and decreases inflammation associated pain.  When injected into arthritic joints, it gives pain relief for 80% of patients (which is the same as either HA or stem cell injections) that lasts about 9 months (which is much longer than HA injections, and almost as much as stem cell injections).  The pain relief provided is as good as, if not better, than that provided by combining HA with steroids.


When injected into injured tendons, PRP accelerates repair.  I find it very useful for the treatment of many shoulder injuries, including biceps tendon, supraspinatus tendon, and rotator cuff injuries.  It can also be used in groin injuries involving the iliopsoas tendon.


Compared to stem cells, PRP is a less invasive and less expensive technique (about 1/3 the cost of stem cell injections).  Depending on the joint or tendon being injected, the entire process can happen with only mild sedation, or even no sedation in some dogs.  However, for advanced tendon repair, stem cells do a better job.


(Mesenchymal) Stem Cells


Mesenchymal stem cells are very different than embryonic stem cells. We only use mesenchymal stem cells in veterinary medicine.  Our bodies constantly undergo some degree of damage and repair, and stem cells are a big part of that repair.  They can be found in many tissues, and once stimulated, will begin to grow new healthy tendon, ligament, or bone.  They are found in high levels in the marrow and periosteum of bone, and play a big role in fracture repair (along with platelets).


In veterinary medicine, we commonly harvest MSCs from two locations: fat, or bone marrow.  Fat derived stem cells are typically sent to an outside lab for processing which often means a second anesthesia for your pet, but bone marrow origin stem cells can be processed and re-implanted immediately as part of the same procedure.


When MSCs were first injected into joints, we were hopeful that they would regrow healthy cartilage and reverse arthritis.  Unfortunately, they do not.  They do however provide good pain control in most patients for 11 months on average (see PRP above).


However, when injected into damaged tendons, MSCs do regrow normal tissue, as well as resorb scar tissue and mineralization.  It is an excellent tool for advanced tendon repair; it is also the treatment of choice for dogs wanting to return to a high level of activity.  Stem cells can also be used to accelerate the healing of broken bones.



Regenerative medicine is fast becoming a key tool for addressing and decreasing the progression of arthritic pain and for treating damaged tendons.  It is an excellent option for owners who want to avoid daily anti-inflammatories or other prescription medications, or for patients who do not tolerate those medications well.

Most shoulder and groin injuries respond well to rehabilitation medicine (the veterinary equivalent of physiotherapy) but for those that don’t, regenerative medicine is often what is needed for dogs to return to full function.


Case Report: Stem Cell treatment of partially torn biceps tendon.


Biceps tendon injury is a common cause of shoulder pain in dogs.  In veterinary medicine, the traditional treatment has been surgical – the tendon is cut from its attachment point so that it is no longer a source of pain.  The problem is that once cut, the tendon is no longer a source of stability for the shoulder and now there is an increased change of incurring other secondary shoulder injuries, including rotator cuff tears. SURGICALLY CUTTING THE BICEPS TENDON SHOULD ONLY BE USED AS A LAST RESORT AFTER ALL OTHER TREATMENTS HAVE FAILED!


Rehabilitation therapy offers a new option for treating this condition and is successful in most minor cases where the amount of tendon tearing is not too great.  However, if rehabilitation therapy on its own is not enough, PRP or stem cell injections are often what is needed.


This is an ultrasound of a damaged biceps tendon that I examined last summer.  Because looking at ultrasound images is a lot like trying to read television static, I’ve added graphics to help.  Healthy tendon should have an even level of “whiteness” on ultrasound, with easily distinguished fibers running along its length.  Damaged tendon has mixed colouring of light and dark tissue, with disruptions of these fibers.Pet Connection BT injury pre-MSC


The two regions coloured blue are the bones of the shoulder joint.  See how the tendon crosses from the upper limb on the right to the shoulder blade on the left?  By spanning the joint, it provides stability to the shoulder, which is why we want to preserve it if at all possible.


The tendon itself is outlined in red.  As you can see, there is quite a bit of colour variation and fibre disruption evident.  This is a badly damaged biceps tendon.  We tried fixing the tendon using rehabilitation therapy techniques, but it didn’t work.  Without some other treatment, this dog would never return to full and pain free activity again.Pet Connection BT injury 3m post-MSC


Here is the same tendon 3 months after injection with stems cells collected from the dog’s bone marrow and injected into the damaged tendon.  See the difference? We anticipate that this dog will return to full activity.


Meet our 2014 Cover Contest Winners

Jack and Jill



Jack and Jill have been a wonderful addition to our family since they were adopted in 2009 from the SPCA in Montreal, after a large raid on a horrific puppy mill. They suffered health and behavioral problems and suffered both physically and emotionally.


Framed_Jill_WPIs a lovable, intelligent and very affectionate Bichon. In the puppy mill she was used for breeding purposes and when we adopted her she was in such bad shape, her little belly was dragging on the ground from having had so many litters. Her veterinary doctor found her so pitiful that while spaying her he did a tummy tuck. At the time he assumed she was about 8 to 10 years old from the terrible shape she was in. She was missing teeth and had a large buildup of tartar on the ones she had left; she was also missing large patches of fur etc… You would never think that she is the same dog we adopted. Today she is a happy dog full of energy and loves to eat. Jill does not hesitate to open her mouth when there is food around. Anything goes. That is one of her favorite things to do, besides cuddling. She is a very vocal dog and has sounds for every emotion she is feeling. She is very playful and loves to wrestle mania with her brother Jack. The more you laugh the more she gets into it.  She is a real little clown.





Framed_Jack_WPIs a playful and curious Wire Fox Terrier blessed with a big stubborn streak that makes everyone laugh. When neutered the doctor assumed that he could have been about 3 or 4 years old. Jack had a lot of issues. He could barely walk, from being locked in a cage; he was very nervous, anxious and extremely afraid of the dark and the wind.  He did not trust people. With much patience, love and coaxing, he has grown into a brave boy. He loves squeaky toys, his favorite is his green froggy. Jack has become a cuddler in his older age. He loves eating fish, carrots, celery and cookies. He does not open his mouth to everything. He has to smell it first and make sure it is edible then he will take it.






Jack and Jill love to run on the beach at grandma’s house in the summer, especially when the tide is low and they can chase the sea gulls (of course the sea gulls always get away). They love their freedom. Jill loves running through the leaves, whereas Jack doesn’t really like stepping on leaves. Jill walks through muddy puddles, Jack will jump over them. In so many ways they are alike, but in so many ways they are different.

We are so happy to give these two precious dogs some enjoyment of life and we can see in their eyes and their affectionate ways that they are so thankful. Little do they know that they have brought us more love than we could ever bring to them.

“All his life he tried to be a good person. Many times, however, he failed.
For after all, he was only human. He wasn’t a dog.”
Charles M. Schulz