02/21/19

Socialisation: More is Better

You do not have to read my blog for long to know that I’m a big fan of puppy socialisation. If you read my Puppies 2012 series, you can see the kind of effort I put into puppy raising five years ago (though my methods are different – better – today!).

One of the problems we have with puppy socialisation is that it’s difficult to test the kind of socialisation that works outside of controlled conditions. A recent study used a standardised socialisation program in assistance dogs, and measured the effects. This is a rare opportunity to have a control group for puppy socialisation (as they were all raised in the same conditions in the breeding facility). And the results were fairly impressive!

Study Basis

Undesirable dog behaviours are problematic. Dogs with problem behaviours may be surrendered to rescue. If they occur in specialised breeding programs (like assistance animals, working animals, or sport animals), then dogs that have unsuitable behaviours are the financial burden of wastage. In the worst case scenario, a dog that is aggressive to people or other animals can cause physical and psychological harms.

In many animals, including dogs, we know that juvenile experiences affect development. Puppyhood may be the time to save adult dogs. For dogs, we know that the crucial social development period is 2-13 weeks of age.

Studies on puppies have suggested that early socialisation causes puppies to:

Mature faster
Explore more
Be more resilient
Perform better on problem-solving task
Be more successful in training

But there is a paucity in dog research. Many studies only look on the short-term impact on puppy development, and do not look at particular socialisation programs. This study wanted to address this paucity.

Study Design

In this study, an assistance dog puppy-raising facility was used. This meant the puppies could be raised in a controlled way. This study used puppies that were golden retrievers, labrador retrievers, or mixes of.

The control group had fourteen puppies who received the centre’s ‘standard’ socialsiation program.

The study group included nineteen puppies who received the standard socialisation program plus ‘extra’ socialisation 5-7 days a week. This extra program took 5 min per puppy in weeks 1-2, 10 minutes per puppy in weeks 3-4, and 15 minutes per puppy in weeks 5-6.

This socialisation program was tailored to the development of the puppies. For example, there’s no point opening and closing an umbrella around a 10 day old puppy. Basically, the socialisation was specific to that age group’s comprehension, and also layered in a way that meant that it wasn’t overwhelming – just appropriate.

It was also important that the program was effective, quick and easy, and low cost.

Below is the programs that the ‘standard socialisation’ and ‘extra socialisation’ puppies were exposed to. It’s actually a little more complicated than this, as there is specific ages that this stimuli should be experienced by the pups, but I went for this simplified version. You can pursue the full text if you really want to know!

Tactile:
-Puppy picked up
-Puppy stroked gently with fingers
-Handle each puppy in the kennel with bitch
-Groom in kennel
The above is standard. Extra in ES is:
-Wearing velcro collar
-Body touched specifically: head, body, tail, legs, paws
-Holding puppy against: woolen jumper, nylon t-shirt, fleece material
-Stroking puppy with soft towel, rubber glove, soft child’s toothbrush
-Puppy encouraged to move over: carpet, rubber matting, reusable shopping bag

Auditory:
-Radio on in the kennel block
-Washing machine sounds
-Plastic bottle with dried pasta inside in kennel with litter
The above is standard. Extra in ES is:
-Sounding near the puppy: a paper bag, a plastic bag, jangling keys, ringing mobile phone, clapping
-Rolling noisy items (e.g. filled toy) in the pen and outside of the pen

Visual:
-Television on in the kennel block
-Push chair in visual range of kennel
-Charity collection box in visual range of the kennel
The above is standard. Extra in ES is:
-Puppy put in front of TV
-Rolling items in and out of the pen
-Hanging items above the stimulation area
-Opening and closing an umbrella
-A mirror (and encouraging exploration of)

Interaction with People:
-Puppy weighed
-Puppy nails clipped
-Puppy carried around block
-Contact with people wearing dress up clothes
-“At least two sessions in a socialisation kennel as a litter”
-Time away from litter
-Grooming on grooming table
The above is standard. Extra ES is:
-Puppy carried around kennel or to socialisation kennel
-Puppy stroked by hand
-Puppy’s teeth and ears examined
-One on one play session for 3 minutes
-Puppy gently restrained for 5-20 seconds
-People wears hat, sun glasses, back pack

Interaction with Environment:
-Empty plastic bottle in kennel with litter
-Toys in kennel to include: soft, plastic, squeaky, rubber, big soft toy
-At least two session on rubber and grass outside areas (that is at least four sessions outside
-Cardboard box in kennel
-Tunnel in kennel
The above is standard. Extra ES is:
-Experience concrete, grass, and rubber surfaces outside
-Puppy encouraged to climb over an obstacle
-Puppy encouraged to move in and out of door ways
-Gently place a towel over puppy and let it find its way out

Then, at six weeks of age and at eight months of age, the puppies were assessed.

At six weeks, the puppies were exposed to six stimuli, and puppy responses were scored on a seven-point scale. It is most desirable for them to get a score of four – but low scores are least desirable. The same trained staff member assessed all puppies, and did so blind (i.e. did not know which puppy was from which program).

Then, at eight weeks, the puppy’s handler was asked to complete a questionnaire of 40 questions, using a bar scale of 0-100. In this tool, low scores were most desirable, except for the trait of trainability. The puppy handler was also blind (i.e. did not know what program their puppy was from).

Study results

We could simply say: it worked. This small amount of extra socialisation resulted in better dogs, at least until 8 months of age.

“This is the first socialisation program tailored to the developmental stage of puppies from birth to six weeks of age to demonstrate measurable, long-term effects on individual dog behavioural traits.”

At all stages of testing (6 weeks, 8 weeks, and 8 months), the puppies who were on the extra socialisation program did better.

Puppies on the extra socialisation program scored better on:

Separation related behaviours,
General anxiety scores,
Body sensitivity scores, and
Distraction.

Additionally, extra socialisation puppies showed more desirable attachment, excitability, and animal chase scores (but this was not statistically significant). There was no affect on trainability or energy scores.

On the Puppy Profiling Assessment (where the perfect score is 4), puppies in the standard socialisation program had a mean score of 3.1, while the ones on the extra socialisation program had a mean score of 3.8.

A puppy exposed to things at a young age is likely, as an adult dog, to treat those things as benign. This reduction in novelty logically affects how dogs behave – they are less anxious and distracted by stuff they’ve seen before.

So what should we do?

To quote the article, “The program is recommended for working dog [including assistant dogs], pet dog breeders and shelters.” This really says what we always knew - everyone breeding dogs should be socialising their puppies. This studied showed that what happens before 8 weeks of age affects the puppy throughout at least the first 8 months of life but, presumably, even longer than that.

Ultimately, people are responsible for shaping the experiences of puppies in their care. Arguing that someone ‘doesn’t have time’ to raise puppies well is illogical, according to this study. The puppies on the extra socialisation program did not receive a great deal more time with people, it’s just the way that time was utilised that varied.

For working dogs, early experiences are particularly relevant due to expense and wastage that results from failure in socialisation – and those working dogs raised in kennel environments are at greater risk again.

This study suggests the extra socialisation puppies spent more time away from their littermates which may also result in these bettered scores. Perhaps this time away from their family for small bouts meant they developed better ways of coping with the stress of permanent separation at 8 weeks.

Regardless, we know that socialisation matters, and more is better!

“Mildly stressful early life experience and challenging situations make animals more resilient to stress, less susceptible to emotional disturbances, and promote motor and cognitive skills in adulthood.”

My Thoughts

This study has a relatively small sample – there are only 33 puppies across the two groups. We need to see this study replicated with larger groups in order to make definitive conclusions.

This study has also put a lot of emphasis on appropriate age of exposure. In a clinical or kennel environment, then this formulaic approach to puppy socialisation is understandable. In more naturalistic settings (i.e. home puppy raisers), I don’t think it’s too important to get fussy about what exactly the puppy is getting exposed to at what age, as long as the puppy is not scared and not oblivious to the stimuli.

The big take home point are: socialisation matters, and it can just take 5-15 minutes a day with a puppy to make a difference to the future adult dog.

Further Reading

This study has also been reviewed by:

Giving Puppies Extra Socialization is Beneficial to Them from Psychology Today

Extra Early Socialization for Puppies Makes a Big Difference from Companion Animal Psychology

Source

Vaterlaws-Whiteside, H & Hartmann, A 2017, ‘Improving puppy behaviour using a new standardised socialisation program’, Applied Animal Behaviour Science, vol 197.

Other Blog Posts

Puppy Socialisation Checklist

Television is Good for Puppies

Puppy Socialisation by Dunbar

Socialisation – Not Everything

08/17/17

Which people get bitten by which dogs?

Dog bites are one of my niche areas of interest, so I when I came across this 2008 bite study, I was keen to read. The overall objective of this study was to work out the similarities between biting dogs and people injured by them, to be able to understand dog bites in such a way that public health could be influenced.

And dog bites are a bit public health problem. In 1986, dog bites were among the top 12 causes of nonfatal injury in the US. in 2005, an estimated 800 000 dog bites needed medical attention in the US. On average, 18 people die per year in the US as a result of dog bites. The number of reported dog bites is going up each year, suggesting this is a growing problem. (Though, personally, I think the number is probably going up to growing intolerance of dog bites in the community.)

So this study was a retrospective cohort study, looking at data for incidents that occurred in the 2002/2003 financial year in Multonomah County, Oregon. In this study period, 636 dog bites were reported to Animal Control Services, while there were 47, 526 dogs licensed in the county.

What followed was a whole lot of number crunching that I don’t entirely understand. From where I’m sitting, it looks like a fair bit of extrapolation went into the figures seen below, but without sampling every single household for dogs and other aspects, I’m not sure if there’s a much better way to go about it.

But regardless, onto the results…

The Biters

From this study, dogs were more likely to bite if:

They were of particular types (terrier, working, herding, and nonsporting),
They were sexually intact and male, and
They were purebred.

Instead of using dog breed, they used dog type, to try to avoid problems in identification. (For example, the general public has a hard time determining between a border collie and coolie, but they do know it’s some kind of herding dog.) The breeds listed above were more likely to bite than dogs that were sporting breeds, hounds, non-AKC breeds, and toy breeds. This study suggested that the dogs in the ‘problematic’ groups have instincts they’re likely to revert to if left untrained (which doesn’t ring true to me for the nonsporting group), and threat they are a ‘size and strength’ to cause damage (which doesn’t seem right considering the size of most terriers).

More intact male dogs bit than any other neuter/sex ratio. This is different to other studies I’ve reviewed.

It’s really perplexing that purebred dogs were more likely to bite in this study. I guess this goes to the breeding practices, but it’s curious to think that crossbreed dogs, presumably bred by people who are ‘accidental’ breeders, end up with less-bitey temperaments. Something for breeders to think about. While these dog factors existed, there was also a range of other elements to a dog bite.

“Factors that determine whether a dog-human interaction will result in a bite are complex and involve characteristics of the dog, the injured person, the owner, and the dog’s environment.”

The Owners of the Biters

Biting dogs were more likely than nonbiting dogs to live in neighbourhoods where the residents’ median incomes were less than the county median income value. If controlling for breed category and controlling for sex, “dogs living in census block groups that had incomes less than the county median were 1.5 times as likely to be reported as a biting dog than reported as a nonbiting dog”. When dog owner data was compared to population density, percentage sex by age, percentage nonwhite race, and percentage without high school diploma, there was still not an association with biting. It was correlated just with income!

So what’s going on here? What’s different in areas were less income? Less money spent on training? On fences? Different attitudes towards child raising? This study suggests that people in these areas may be inclined to select particular breeds (i.e. especially those with reputations for aggressive behaviours). (Though this study didn’t look at whether some breeds were more likely to be owned by different groups.) They also suggest that low income areas may socialise their dogs in a different way, and therefore change the bite potential of the dog, or perhaps they’re not trained or supervised in a way that minimises dog bite risk.

“In another study examining dog bite injuries in St Louis, Mo, bite injuries occurring in low income areas were attributed to large numbers of children playing outdoors, few homes with adequate fencing, poor dog control, and a high proportion of large-breed dogs owned for protective purposes.”

As a personal comment, in my experience, crossbreed large dogs are cheaper than small dogs or purebred dogs. This means low income areas are likely to own bigger dogs, and we know bigger dogs are more likely to have their bites reported. While studies of the past have looked at breed and sex-neuter status, this study reveals a new area for further research: block group income levels.

But there’s more: It’s not just about the dog and who owns it, but also where the bite took place.

The Place of the Bites

Dog bites occurred:

35.1% of bites happened in the dog’s home or yard.
23.4% of bites happened in ‘neutral territory’
17% of bites happened in dog/victim household (i.e. the parties lived together)
10.1% of bites happened in household of victim (not dog’s place)
7.1% bites unknown place
3.8% at “place of employment” – e.g. vet clinic, rooming facility, MCAC
3.6% “Neighbour’s Property” (which could be grouped with the 35.1%)

This reinstates the idea that parents need to be extra vigilant when they are visiting houses with dogs.

Other Statistics

Other tid bits of interest:

Boys and girls aged 5-9 years had highest rate of injury, boys a bit higher (but not significantly so).
Of the 636 biting dogs, 49% had a license number. There are some estimates that less than half of all dogs are registered. (I really wonder what this kind of statistic would look like in Australia.)
36% of dog bite victims didn’t know the dog that bit them. (The largest portion.)
But: Among children, 46% were bitten by the family dog.
More dog bites in summer months.
No significant difference between male and females being bitten.

Limitations

Like all studies, there are a number of problems. In this study, the results are limited by.

Not all dog bites will be reported. Dog bites are a reportable incident in Oregon, but the records are incomplete. There’s a problem with recording of dog bites. A previous study, referenced in this one, suggested that only 17% of bites are reported to any authority. (And while this may be the case, how else should we be analysing dog bites except through dog bite records? This model is probably the best we have.)
We know members of the public are not very good at reporting dog bites by breeds.
Dog license data can only be used as an estimate of breed-populations – especially because we know perhaps only half of all dogs are registered. Further, if owners of some breeds are less likely to license their dogs, the breed specific bite rates are further skewed.
When a large-breed bites, that bite is more likely to be reported and more likely to need medical care, meaning that there is a reporting bias that can increase the number of these dogs seemingly involved in incidents.

Conclusion

This study made recommendations for reducing dog bites:

Combined approaches from human medical communities, veterinary communities, and animal control to help foster healthy relationships between people and pets.
Focus on low income neighbourhoods.
Paediatricians to counsel parents (dog owning and not) on dog safety during routine medical visits.
Low cost spay neuter.
Education programs (perhaps through animal control).

“Innate tendencies dictated by breed, sex-neuter status, and size play a role in the potential of a dog to bite, but owners are ultimately responsible for their dogs’ action[,]… and need to make every effort to minimisze their dogs’ bite potential through obedience training; neutering; and supervision, especially around children.”

Source:

Shuler, CM, DeBess, EE, Lapidus, JA, and Hedberg, K 2008, “Canine and human factors related to dog bite injuries”, JAVMA, vol 232, no 4.

07/16/17

Litter Size – What the research says

There is an ongoing paucity in the literature surrounding most dog matters, and that means dog knowledge is often based on anecdotes and experience instead of facts and figures. Dog breeding is no exception. Breeders will tell you that they get bigger litters if x, smaller litters if y, that they’ll never mate a bitch if z. While personal experiences can provide case studies, I am interested in much bigger data.

Enter a Norwegian study looking at 10,810 litters.

This study used data held by the Norwegian Kennel Club to look at every litter registered in 2006 and 2007, across 224 breeds. Statistical analysis was then done to determine all the wonderful figures summarised below.

The aim of this study was to determine what actually makes a difference in litter size. (Litter size being the number of puppies born, alive or dead.)

Firstly, an overall average had to be determined. For this data set, the average litter size, considering all breeds, was 5.4 puppies.

For those interested in average litter size by breed: The largest average litter size was in the Rhodesian Ridgeback with an average of 8.9 pups per litter. The Toy Poodle and Pomeranian had the smallest average litter size – 2.4 pups per litter. And the Border Terrier (because I’m biased) had an average litter size of 5.1 pups per litter.

This study found that litter size was influenced by the size of the breed, the method of mating, and the age of the bitch. Litter size was not affected by season of birth, or the number of litters a bitch had had.

Size of the breed

This study examined dogs based on average breed size. They were classed as miniature breeds (<5kgs), small breeds (5-10kgs), medium breeds (10-25kgs), large breeds (25-45kgs), and giant breeds (>45kgs). Bitches were recorded against the average size of a dog for their breed and not specifically on the size of that given bitch.

“When looking at all the … litters…, mean litter size increased with the size of the breed. The mean litter size was 3.5 in miniature breeds, 4.2 in small breeds, 5.7 in medium breeds, 6.9 in large breeds, and 7.1 in giant breeds.”

The feature of larger dog breeds having larger litters is not a new thing – this phenomena is consistent across other studies. But this study is different as it found that it wasn’t just size of the breed that mattered…

Age of the bitch

The first analysis of this data showed no significance with the age of the bitch, however, once breed size was taken into account, there were two trends apparent:

In small and miniature dogs, young and old bitches had smaller litters than the ages in between.
In larger breeds, increasing age corresponded with decreasing litter size. (Young bitches of larger breeds produced the largest litters – unlike small and miniature breeds.)

These results are a little different to other studies, which have shown smaller litter sizes as bitches get older. (As in, the results this study got for larger breeds was seen in all breeds in previous studies.) It could be that smaller sample sizes in other studies may have missed this, or that other studies used larger breeds as their data set instead of small or miniature breeds. One suggestion is that small breeds may not mature as quickly as previously believed, and so they’re not able to reproduce until they reach that mark. (To me, this kind of makes sense – considering small breeds often live longer, then it’s likely that they mature more slowly, too.)

Method of mating

Like the age of the bitch, the first analysis on the data didn’t show a significance change in litter size based on mating method. However, when the data set was adjusted for breed, breed size, and age, naturally mated bitches had significantly larger litters than those who had been AIed (either fresh or frozen).

A decrease in mean litter size of 0.4 puppies would be expected for litters conceived with AI with fresh semen and 1.3 for AI with frozen semen, both compared to natural mating.

Things that didn’t matter

The number of litters a bitch had previously didn’t influence the size of her litter. (However, older bitches normally had had more litters – and their age did influence litter size.)

The season the litter was born in did not influence litter size.

Conclusion

Size of the breed, age of the bitch, and the method of mating are three factors that work together in determining litter size. It’s not one thing – it’s all three.

“… the size of the breed, the age of the bitch and the method of mating were found to influence litter size in purebred dogs when controlling for breed, with the size of the breed as the strongest determinant.”

This study is better than past studies in this area for its huge sample size, its variety of breeds, and the fact that it considers all puppies in a litter (not just those registered, as some past studies have done). In this way this study is unique. It is probably a pretty reliable data pool for purebred dogs, too, as 90% of purebred dogs in Norway are registered with their kennel club.

Things to consider regarding the vigour of the results:

It’s a retrospective study.
It does not include data from litters where all pups were born dead.
Calculating mean litter size is hard, because of the percentage made up of small or large breeds. Small breeds are currently popular, so could perhaps pull down the mean litter size seen in this study. Studies done in different countries, with different breeds being popular, are likely to result in different results.
There is a relatively small sample of bitches who were mated not-naturally in this study, so the results of assisted breedings should be interpreted cautiously, however the results are consistent with previous findings.
This study only groups dogs by weight – not by body shape. This might yield differences. (A neapolitan mastiff is really different to a greyhound.) And they group them by weight average of breed, not the weight of the individual bitch
This study looked at only two years and the researchers wonder if there might have been more variation in season of birth if there was more time taken into consideration.

In conclusion: Based on this study, breed size is the strongest determinant for litter size in a dog. The age of the bitch and the method of mating were also significant predictors of litter size. These three things interact, making litter size predictions difficult!

Acknowledgements:

Borge, KS, Tonnessen, R, Nodtvedt, A, & Indrebo, A 2011, “Litter size at birth in purebred dogs – A retrospective study of 224 Breeds”, Theriogenology, 75, 911-919.

Thank-you to Waldwiese Kennels for the cover image – a litter of longhair weimaraner puppies.

02/25/14

Vaccinations Last At Least Three Years

When reading Terrierman he made reference to the work Schultz has done on the duration of vaccines. Intrigued, I decided to read one of his articles. I dug up a review Shultz wrote on the duration of vaccines. It looks at available research on vaccines and their ‘duration of vaccinal immunity’ (i.e. how long they last).

Whether a dog has immunity can be determined either by antibody titres (a ‘titre test’) or a challenge study (e.g. deliberately exposing the dogs to the pathogen).

For distemper, parvovirus, and adenovirus the published data suggests an immunity period of 3 years or longer minimum.

Using blood products to test immunity, it seems that vaccines last 3 years or longer. When using challenge studies, dogs that were vaccinated 11 years ago did not contract the virus.

According to this article, if a cat or dog is:

Vaccinated with core vaccines at 12 weeks of age or older,
Is revaccinated at 1 year old, and
Receives a vaccination “not more often than every 3 years”

then this would be as protective to the pet as annual vaccination.

However, non-core vaccinations last a year or less.

Table 1 shows estimated minimum duration of immunity for the 4 core canine vaccines.

How long does a dog vaccination last?

Shultz concludes, “Extending the revaccination intervals for canine and feline core vaccines does not place the animal at increased risk to developing vaccine preventable disease, but it does reduce the potential for adverse reactions”

He also recommends using titre tests to ensure that a puppy’s final vaccine enduces an immune response – and to revaccinate if the titre does not indicate that an immune response was produced.

Oh, and on cats? According to this paper, feline vaccines less researched, but feline parvovirus, calcivirus and herpes seems to last at least 7.5 years. Exception is feline leukemia which provides immunity for 1 year or less.

Reference:
Ronald D. Schultz (2006). Duration of immunity for canine and feline vaccines: A review Veterinary Microbiology, 117 (1), 75-79 DOI: 10.1016/j.vetmic.2006.04.013

02/4/14

Aggressive Breeds via Owner Accounts

Establishing ‘aggressive breeds’ without using dog bite data: Using owner reports to establish the most aggressive dog breeds

In 2008, data was published on the ‘most aggressive dogs breeds’, with dachshunds, chihuahuas, and jack russells, coming out on top. Recently, various media reports having been reappearing on my newsfeed on this study, with titles like “The 3 Most Aggressive Breeds Revealed“.

Before we begin, please do acknowledge that I adamantly against BSL. I am heavily influenced by research and evidence and, currently, all the evidence points to breed specific legislation never being effective in reducing the incidence of dog bites, in any place globally.

That being said, because I am interested in science, I am interested in studies like this.

So what can this study teach us about aggression in particular dog breeds?

Cindy the Jack Russell Terrier: In the top three aggressive breeds according to this study.

A Jack Russell Terrier: in the top three aggressive breeds according to this study.

The Flaws in Breed Aggression Research

Aggression is a difficult characteristic to assess in dogs. There are a variety of methods that researchers have used, and all have their ‘downsides’.

Using dog bite statistics is not the best course, as most dog bites go unreported, the dog breeds involved cannot be verified and, even if they are verified, it is impossible to understand how many dogs of that paricular breed exist in the community.

If you’re only looking at caseloads from behavioural clinics, then this data is likely to be biased. Generally, people with larger and more dangerous (because of their size) dogs are more likely to seek help, as are people who have dogs aggressive to members of their family. (This article doesn’t mention it, but finances also play a role here – only those owners with the finances to attend behavioural clinics would be represented in such a study.)

There has been some popularity in behavioural tests (cough – D&CMB proposal – cough) where they do threatening or scary things to a dog and score their responses. The problem with this is how this actually relates to the ‘real world’ and the aggression the dog displays in everyday life.

When you ask owners about their dog’s behaviour, their experiences and responses are subjective. And ‘experts’ aren’t much better, with many of them representing ‘shared stereotypes’ whether conclusions from their own experiences.

Study Design

In this particular study, C-BARQ was used. C-BARQ has a good record as being pretty reliable when it comes to asking owners what their dogs are like, temperamentally.

Members of 11 AKC club (‘club sample’) and vet clinic clients (‘online sample’) were invited to partake.

1,553 C-BARQs were completed by the club sample, with 29 excluded as they did not meet criteria.

8,260 C-BARQs were completed by the online sample, with 1,257 excluded for being mixed breeds or with no breed indicated, and 2,051 excluded as there was less than 45 of that breed represented – so in the end the sample was 4,952 responses for 33 different breeds.

They were rated on aggression towards strangers, owners, and other dogs.

Summarised Findings

The online sample and breed club sample differed in some ways. Breed clubs submitted more intact dogs, more female dogs, and older dogs than those in the online sample. Despite this, the results were quite consistent across the two samples.

Dog aggression was the most common and most severe type of aggression in the study, but dog aggression was not correlated with aggression to people. This supports the widely held view that ‘dog aggression’ does not indicate a risk to people. Similarly, aggression towards household-dogs was not associated with aggression towards other dogs or people. From the data in this study, more than 20% of Akitas, Jack Russell Terriers, and Pit Bulls had serious aggression towards unfamiliar dogs.

When it came to aggression towards people, the highest rates were found in smaller breeds, ‘presumably’ because aggression from smaller (and so more manageable and less dangerous) dogs is more tolerable.

When it came to aggression towards owners, more than half of the aggressive displays towards owners were associated with the owner taking food or something else away from the dog.

While fear in animals is associated with aggression, fear was not strongly correlated with aggression in this study. Some dogs were aggressive but not fearful, some were fearful but not aggressive, and some were fearful and aggressive.

A quote from the study on their findings,

“Although some breeds appeared to be aggressive in most contexts (e.g., Dachshunds, Chihuahuas and Jack Russell Terriers), others were more specific. Aggression in Akitas, Siberian Huskies, and Pit Bull Terriers, for instance, were primarily directed toward unfamiliar dogs. These findings suggest that aggression in dogs may be relatively target specific, and that independent mechanisms may mediate the expression of different forms of aggression.”

Screen shot 2014-02-02 at 5.01.31 PM

Further results on a more breed-by-breed basis (breeds listed alphabetically):

Akitas rated higher for aggression towards other dogs than other breeds.
American Cocker Spaniels rated higher for aggression towards their owners than other breeds.
Australian Cattle Dogs rated higher for aggression towards other dogs than other breeds, and also rater higher for aggression towards strangers.
Basset Hounds rated higher for aggression towards their owners than other breeds, but were below average when it came to stranger directed aggression.
Beagles rated higher for aggression towards their owners than other breeds.
Bernese Mountain Dogs were among the breeds least aggressive towards people and dogs, and ranked below average on stranger directed aggression.
Boxers rated higher for aggression towards other dogs than other breeds.
Brittanys were among the breeds least aggressive towards people and dogs, and ranked below average on stranger directed aggression.
Chihuahuas rated higher for aggression towards people (both owners and strangers) and higher for aggression towards other dogs than other breeds.
Dachshunds rated higher for aggression towards people (both owners and strangers) and higher for aggression towards other dogs than other breeds.
English Springer Spaniels rated higher for aggression towards other dogs than other breeds, and also rated higher for aggression towards owners. Showed bred English Springer Spaniels were more aggressive than field bred lines.
German Shepherd Dogs rated higher for aggression towards other dogs than other breeds.
Golden Retrievers were among the breeds least aggressive towards people and dogs, and ranked below average on stranger directed aggression.
Greyhounds were among the breeds least aggressive towards people and dogs, and ranked below average on stranger directed aggression.
Jack Russell Terriers rated higher for aggression towards people (both owners and strangers) than other breeds and higher for aggression towards other dogs than other breeds.
Labrador Retrievers were among the breeds least aggressive towards people and dogs, and ranked below average on stranger directed aggression. Field bred labradors were more aggressive than show bred labradors.
Pit Bulls rated higher for aggression towards other dogs than other breeds.
Siberian Huskies ranked below average on stranger directed aggression.
West Highland White Terriers rated higher for aggression towards other dogs than other breeds.
Whippets were among the breeds least aggressive towards people and dogs, and ranked below average on stranger directed aggression.

Warning against reaching conclusions on the genetic basis of aggression…

The authors caution, “Demographic and environmental risk factors for the development of canine aggression need to be investigated across a variety of breeds so that both generalized and breed-specific influences can be identified.”

So what do you think? Are these studies results consistent with your experiences?

Reference:

Deborah L. Duffy, Yuying Hsu, & James A. Serpell (2008). Breed differences in canine aggression Applied Animal Behaviour Science, 114 (3), 441-460 DOI: 10.1016/j.applanim.2008.04.006

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