Category Archives: research

Research reveals overweight dogs may live shorter lives

New research from the University of Liverpool and Mars Petcare’s WALTHAM Centre for Pet Nutrition reveals overweight dogs are more likely to have shorter lives than those at ideal body weights.

Results from the study, conducted retrospectively across two decades and published in the Journal of Veterinary Internal Medicine, revealed the lifespan of dogs that were overweight was up to two and a half years shorter when compared to ideal-weight dogs.

fat bulldog

The study examined more than 50,000 dogs across 12 of the most popular dog breeds. The effect of being overweight was seen in all breeds, although the magnitude of the effect differed, ranging from between five months less for male German Shepherds to two years and six months less for male Yorkshire Terriers.

Poorer quality of life

It is estimated that over a quarter of households (26%) in the UK and nearly half in the US (47.6%) own a dog. However despite our affection for canine companions, concern is growing that many pet owners are unaware of the serious health implications of dogs carrying extra weight. Pet obesity is steadily on the rise, with latest figures estimating one in three dogs and cats in the U.S. is overweight.

Although the study did not examine the reasons behind the extra pounds in dogs, feeding habits are thought to play a role in pet obesity. According to a recent Better Cities For Pets survey , more than half (54%) of cat and dog owners always or often give their pet food if they beg for it, and nearly a quarter (22%) of cat and dog owners sometimes overfeed their pet to keep them happy.

Study co-author and Professor of Small Animal Medicine at the University of Liverpool Alex German, said: “Owners are often unaware that their dog is overweight, and many may not realise the impact that it can have on health. What they may not know is that, if their beloved pet is too heavy, they are more likely to suffer from other problems such as joint disease, breathing issues, and certain types of cancer, as well as having a poorer quality of life. These health and wellbeing issues can significantly impact how long they live.

“For many owners, giving food, particularly tasty table scraps and tidbits, is the way we show affection for our pets. Being careful about what you feed your dog could go a long way to keeping them in good shape and enabling them to be around for many years to come.
“Worryingly, it is estimated only one in five pet owners always measures how much food they are giving their pet, with four in five (87%) always or often simply estimating the amount of food they think their pet needs at each serving.”

About the Study

The University of Liverpool and WALTHAM study was a retrospective, observational cohort study that leveraged demographic, geographic and clinical data from dogs that received care at BANFIELD® Pet Hospitals between April 1994 and September 2015. Data were available from 50,787 dogs across 12 of the most popular family breeds: Dachshund, German Shepherd, Golden Retriever, Labrador Retriever, American Cocker Spaniel, Beagle, Boxer, Chihuahua, Pit Bull Terrier, Pomeranian, Shih Tzu, and Yorkshire Terrier. For each breed, the lifespan dogs whose owners reported them to be overweight and those in optimal body condition was compared.

As the largest general-veterinary practice in the world, Banfield has more than 1,000 hospitals across the United States and Puerto Rico comprised of veterinary teams who are committed to providing high-quality veterinary care for more than three million pets annually. The data extracted for this study included demographic (breed, sex, neuter status and date of birth) and geographic (latitude and longitude of the owner’s postcode) variables, plus data collected during in-clinic visits (date of visit, bodyweight and if available body condition), and date of death. Pedigree status and date of birth are both owner-reported parameters and were not verified by veterinary staff.

Source:  University of Liverpool

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For gait transitions, stability often trumps energy savings

A dog’s gait, according to the American Kennel Club, is “the pattern of footsteps at various rates of speed, each distinguished by a particular rhythm and footfall.” When dogs trot, for example, the right front leg and the left hind leg move together. This is an intermediate gait, faster than walking but slower than running.

In the December 12, 2018 issue of the Proceedings of the Royal Society B, a multi-institutional team of researchers based at the University of Chicago Medical Center take a novel and wide-ranging approach to understanding such speed-related gait transitions. The generally accepted approach has long focused on reducing locomotor costs, essentially finding the least taxing way to ramp up from one gait to a faster one without wasting energy.

gait transitions

Each animal ran in the metabolic chamber two to five times a day. From these metrics it was possible to determine the energetic costs of running at a particular speed. Credit: Caleb Bryce from the Botswana Predator Conservation Trust

The researchers, however, uncovered a different explanation. They chose to focus less on energy conservation and more on locomotor instability–in layman’s terms, reducing the risk of stumbling or toppling over. Their findings suggest that gait transitions represent “predictive, anticipatory switching of movements to minimize unstable dynamic states.”

“We found that gait transitions occur when the stability of a gait decreases so much that switching to a new gait improves stability,” said Michael Granatosky, PhD, lead author of the study and a post-doctoral student in the department of Organismal Biology and Anatomy at the University of Chicago. “The mammals and birds we studied tend to make gait transitions at critical points to provide a more rhythmic, less unstable locomotor state.”

These transitions, he added, can minimize “high inter-stride variation and unstable dynamic states, reducing the risk of inter-limb interference, such as tripping or falling.”

This wide-ranging study focused on gait transitions in nine animal models–seven mammals and two birds. The researchers started with Virginia opossums, tufted capuchins (“organ grinder” monkeys) and domestic dogs.

They subsequently found similar data on gait transitions in six additional species: American minks, Australian water rats, brush-tailed bettongs (small marsupials also known as rat kangaroos), ostriches, North American river otters and the Svalbard rock ptarmigan.

All of the initial animals–dogs, monkeys and opossums–were trained to exercise at a range of speeds on a treadmill within a plexiglass metabolic chamber. This familiarized the animals with the treadmills while improving their physical fitness. By the end of the training period, all of the animals could sustain six to ten minutes of vigorous running at “speeds required for metabolic movements.”

Once the training was completed, the researchers began testing. They monitored oxygen uptake, carbon-dioxide production, temperature, moisture levels, barometric pressure and air flow. Each animal ran in the chamber two to five times a day. From these metrics it was possible to determine the energetic costs of running at a particular speed.

These energetic costs were collected over a range of speeds during walking and running. Variations in stride cycle duration were collected for each speed interval.

Based on the data collected from this broad phylogenetic range of species, the authors determined that the assumptions of the energetic minimization hypothesis for gait transitions were rarely met.

Instead, most animals choose not to switch gaits when it was most energetically efficient. In this study, dogs, ptarmigans, ostriches and otters, showed no significant change in the energy cost of transport while switching from a walk to a faster mode. In contrast, almost all of the other species demonstrated high variability near gait transitions. They subsequently reduced variability after switching to a new more stable gait.

“Energy savings do not predict gait transition patterns,” the authors conclude. Instead, gait transitions “maintain dynamic stability across a range of speeds.”

“Our data,” the authors conclude, “suggest that gait transitions represent predictive, anticipatory switching of movement types to minimize high variability and avoid unstable dynamic states.” Birds and mammals, they added, appear to have evolved sensorimotor mechanisms for monitoring inter-stride stability during locomotion and for triggering gait transitions at critical levels of variation.

Source:  EurekAlert!

Training children and adults in dog body language

A better understanding of the way dogs communicate distress could be the first step in reducing the risk of dog bites for both children and adults, a new study has found.

Psychologists investigating how children and parents perceive and interpret dog’s body language found that both groups significantly underestimate and misinterpret the way that dogs display distress or anxiety, including behaviours such as snarling or growling which can cause a significant risk to children.

Lip licking dog
The project consisted of three phases involving children aged three, four and five years old and one group of parents. Initially, each group was shown a series of short video clips of dogs displaying a full range of behavioural signals which ranged from happy dogs through to high-risk conflict-escalating behaviours such as growling, snarling or biting. Participants were then asked to rate their perception of the behaviours on a simple, child-friendly scale from ‘very happy’ to ‘very unhappy/very angry’.

The groups then took part in a training phase where the videos were repeated, this time accompanied by simple information explaining the type of behaviour the dog was displaying, for example, ‘the dog is licking its nose’, how to interpret the behaviour – i.e. the dog is worried, followed by a safety message such as ‘you should leave the dog alone’. Participants then also saw novel videos with all behaviours. Once the training phase was completed, participants were immediately tested to establish their judgements of the dogs’ behaviours then testing again after six months and after one year to measure whether the training had a lasting effect.

Results showed that younger children found it harder to correctly interpret dog distress signals with 53 per cent of three year olds misinterpreting high risk signals such as growling or snarling. Of the children who made mistakes, 65 per cent thought that these dogs were happy. Results showed 17per cent of the parents also incorrectly interpreted these behaviours.

After the training intervention, both children and adults showed better understanding. Most improvement was found on conflict-escalating signals such as staring, growling or snarling with adults and older children showing the highest levels of improvement. Pre-training, only 55 per cent of four year olds were able to correctly interpret high risk dog behaviours with this rising to 72 per cent post training. The training was also shown to have a lasting effect with the figure rising to 76 per cent twelve months post-training.

Lead researcher Professor Kerstin Meints from the University of Lincoln’s School of Psychology said: “We observed that children often try to apply an explanation for the dog’s signals that would be appropriate to explain human behaviour. For example, children often wrongly interpreted a dog snarling and showing its teeth to mean that the dog was happy, which could put them at significant risk if they were to approach a dog displaying these signals.

“This project is the first to offer an intervention to significantly enhance children’s and adults’ abilities to correctly interpret dog signalling and has shown that with simple training we can improve their awareness, knowledge, recognition and interpretation skills.”

Journal citation:  Teaching Children and Parents to Understand Dog Signalling, Frontiers in Veterinary Science, https://www.frontiersin.org/articles/10.3389/fvets.2018.00257/full

Source:  University of Lincoln media release

Women sleep better with dogs than with human partners

There are many dog trainers who advise against letting your dog sleep with you in bed.  Some new research by Dr Christy Hoffman at the Canisius College will challenge that notion.

Izzy the greyhound in bed

In a survey of 962 women living in the United States, dogs who slept with their female owners were found to disturb sleep less than a human counterpart and they provided stronger feelings of comfort and security.

Dogs’ sleep patterns more closely coincide with sleep patterns in humans than do the sleep patterns of cats, which may explain why dog moms stick to a stricter sleep schedule and go to bed earlier.

Cats didn’t fare quite as well in this research.  Cats were reported to be equally disruptive as human partners and were associated with weaker feelings of comfort and security compared to dogs or humans.

Journal citation:  An Examination of Adult Women’s Sleep Quality and Sleep Routines in Relation to Pet Ownership and Bedsharing

Source:  Canisius College

Your dog’s water bowl: microbiology

This research was delivered to the 69th Annual Meeting of the European Federation of Animal Science meeting in August 2018.

It’s important to clean your dog’s water bowl regularly – don’t be tempted to simply keep filling it up because bacteria grows on the sides of the bowl.  (Run your finger over it and you’ll probably feel a slippery surface – that’s called biofilm)

I personally like stainless steel bowls because they can be washed in very hot water in the dishwasher and because they are durable and recyclable.

Dog water bowl


The number of pet dogs (Canis lupus familiaris) in the common household is continually rising. The increasingly close contact between humans and cohabitant pets is leading to concerns regarding bacterial transmission of zoonoses. The dog water bowl has been identified as the third most contaminated item within the household, suggesting that it is able to act as a fomite for bacterial transmission, particularly where young or immunocompromised individuals are present.

Studies in livestock have identified that water trough construction material influences bacterial count; however no similar research has been conducted for dog water bowls.

The objectives of the current study were to identify which dog bowl material, plastic, ceramic or stainless steel, harbours the most bacteria over a 14 day period and whether the species identified varies between bowl materials. The study took place over 6 weeks. A sample of 6, medium sized (10-25kg) dogs, aged 2-7 (mean= 3.8 ± 1.95), was used. All dogs were clinically healthy, housed individually and located within a rural environment. All bowls were purchased brand new and sterilised prior to a two week sampling period.

On day 0, day 7 and day 14 swabs were taken from each bowl and 10-fold serial dilutions were conducted on blood agar. The cultured bacteria were subjected to biochemical testing and the most prominent bacteria from day 14 were further identified using PCR. A significant difference was identified for all bowl materials when comparing total CFU/ml between day 0 and day 7 and day 0 and day 14 (p<0.05). No significant difference was identified between total CFU/ml and bowl material (P>0.05), however descriptive statistics suggest that the plastic bowl material maintains the highest bacterial count after 14 days.

Several medically important bacteria were identified from the bowls, including MRSA and Salmonella, with the majority of species being identified from the ceramic bowl. This could suggest that harmful bacteria may be able to develop biofilms more successfully on ceramic materials. Further research is required to identify the most suitable or alternative materials for dog water bowls.

Source: Microbiological Assessment of Canine Drinking Water and the Impact of Bowl Construction Material

A ‘Robo-Nose’ Could Give K-9 Officers a Break

Robonose golden retriever

Golden retriever Rudy, wearing military dog tags and a U.S. flag, is being trained by the U.S. Army to use his amazing nose to find human remains. (Army photo)

Every day, thousands of trained K9 dogs sniff out narcotics, explosives and missing people across the United States. These dogs are invaluable for security, but they’re also very expensive and they can get tired.

Duke researchers have taken the first steps toward building an artificial “robot nose” device made from living mouse cells that officers could use instead of dogs.

The researchers have developed a prototype based on odor receptors grown from the genes of mice that respond to target odors, including the smells of cocaine and explosives. Their work appeared earlier this month in Nature Communications.

It turns out, there are a couple of very big differences between testing things in a lab dish and testing them in an actual nose.

“This idea of an artificial nose has been present for a long time,” said senior study author Hiroaki Matsunami, a professor of molecular genetics and microbiology in the Duke School of Medicine. “The receptors were identified in the 1990s, but there are significant technical hurdles to produce all these receptors and monitor the activity so that we can use that in an artificial device.”

“E-noses” that exist now use various chemical compounds to detect smells instead of receptor stem cells, Matsunami said. He said those devices are “not as good as a trained dog.”

“The idea is that by using the actual, living receptors, maybe we can develop a device similar to animals,” Matsunami said. “Nobody has achieved that yet, but this study is moving toward that goal.”

Human, dog and mouse genomes contain around 20,000 genes, which contain instructions to create proteins that smell, taste, feel, move and do everything that our bodies do. About 5 percent of mouse genes have been identified as instructions to make odor receptors, Matsunami said. In contrast, humans only use about 2 percent of their genes to make odor receptors.

“These animals invest a lot of resources for this purpose,” Matsunami said. “Mice and rats are very good smellers; we just don’t use mice for detecting explosives in real life. There are some practical problems to do that.”

The first step of the study was to identify the best odor receptors to respond to target odors like cocaine or marijuana.

The researchers created a liquid medium primed with molecules that could light up from reactions. Next they copied about 80 percent of the odor receptors from mice, and mixed those receptors with seven target odor chemicals in the medium.

They measured the resulting luminescence and chose the best-performing odor receptors for the second part of the study, which monitored receptor activation in real time.

Previous research had done this by exposing selected receptors to odor chemicals in a liquid. But there are several differences between the petri dish and the nose. For one, we rarely submerge our noses into liquid baths of odor chemicals. Instead, our noses detect smells from wafting perfumes or stenches borne on the air. And our noses are full of mucus.

So, for the second half of the study, which was supported by the National Institute of Health grants DC014423 and DC016224 and the Defense Advanced Research Project Agency RealNose Project, they attempted to mimic how we use our noses by exposing odorants to vapors and a few enzymes.

The researchers tested the receptors they had identified against two odor vapors for this study.

“We only tested two of them in the paper, but it’s showing the proof of principle of how it can be used,” Matsunami said.

The researchers hope they can fine-tune the device to test all receptors against many different smells.

“We have a panel of receptors so we can monitor how different receptors respond differently to various smells, including ones that are similar to each other in chemical structure or ones that might be related to real-world use, like something associated to explosives or drugs,” Matsunami said.

The researchers also tested various enzymes that one might find in mucus to see how they aided or impeded reactions. This process is more true-to-life than vapor molecules directly interacting with odor receptors.

“You’d think when we smell a chemical, the chemical would bind to the chemical receptor in the nose, but actually it’s not so simple,” Matsunami said. “When the chemical dissolves in the nasal mucus before binding to the receptor, it might be converted to another chemical by enzymes in the nasal mucus.”

Mucus is an unknown frontier in understanding how we smell. Reconstructing the key components of nasal mucus may be the next step toward building an artificial nose, according to the paper.

“It’s not like our paper will be immediately applied to a portable device used in the airport soon, but this is an important step forward to show that it is possible,” Matsunami said. “We can more clearly see what kind of hurdles to pass in order for the community to create such a device.”

Three of the authors have filed a patent application for the work.

Source:  Duke University

Dogs know when they don’t know

When they don’t have enough information to make an accurate decision, dogs will search for more – similarly to chimpanzees and humans.

Researchers at the DogStudies lab at the Max Planck Institute for the Science of Human History have shown that dogs possess some “metacognitive” abilities – specifically, they are aware of when they do not have enough information to solve a problem and will actively seek more information, similarly to primates. To investigate this, the researchers created a test in which dogs had to find a reward – a toy or food – behind one of two fences. They found that the dogs looked for additional information significantly more often when they had not seen where the reward was hidden.

Metacognition study

In this study, dogs showed some of the signs of metacognition, specifically that they searched for more information when they had not seen where a reward was placed. © Juliane Bräuer

In the field of comparative psychology, researchers study animals in order to learn about the evolution of various traits and what this can tell us about ourselves. At the DogStudies lab at the Max Planck Institute for the Science of Human History, project leader Juliane Bräuer studies dogs to make these comparisons. In a recent study published in the journal Learning & Behavior, Bräuer and colleague Julia Belger, now of the Max Planck Institute for Human Cognitive and Brain Sciences, explore whether dogs have metacognitive abilities – sometimes described as the ability to “know what one knows” – and in particular whether they are aware of what information they have learned and whether they need more information.

To test this, the researchers designed an apparatus involving two V-shaped fences. A reward, either food or a toy, would be placed by one researcher behind one of the two fences while another researcher held the dog. In some cases, the dog could see where the reward was placed, while in others the dog could not. The researchers then analyzed how frequently the dogs looked through a gap in the fence before choosing an option. The question was whether, like chimps and humans, the dog would “check” through the gap when he or she had not seen where the reward was placed. This would indicate that the dog was aware that he or she did not know where the reward was – a metacognitive ability – and would try to get more information before choosing a fence.

Experiment set up

The overall set-up of the experiment, showing the two V-shaped fences, the experimenter who places the reward, the experimenter holding the dog, and the dog in starting position, without a curtain to block the view. This dog was participating in the third variation, with a time delay. © DogStudies. Belger & Bräuer, 2018. Metacognition in dogs: Do dogs know they could be wrong? Learning & Behavior. DOI: 10.3758/s13420-018-0367-5.

Some researchers argue that some animals, such as dogs, may only look for extra information when searching as a routinized, instinctual behavior, and not as a result of a metacognitive process. To control for this, Bräuer and Belger tested whether dogs show the so-called “passport effect,” originally described by researcher Joseph Call. When humans are looking for something very important, for example, a passport, they will engage in more active searching and will check for it more often than if they are looking for something less important or generic. Great apes display this same behavior – they will search more for a high-value food. Thus, Bräuer and Belger varied whether the dogs were looking for high- or low-value food, in order to test whether dogs also had the searching flexibility displayed in the passport effect. In another variation, they tested whether it made a difference to the dog when they had to search for a toy or for food.

The dogs “checked” more often when they did not know where the reward was hidden

The researchers found that the dogs did check significantly more often for the reward when they had not seen where it was placed. “These results show that dogs do tend to actively seek extra information when they have not seen where a reward is hidden,” explains Belger. “The fact that dogs checked more when they had no knowledge of the reward’s location could suggest that dogs show metacognitive abilities, as they meet one of the assumptions of knowing about knowing.”

Checking, however, did not always make the dogs very much more successful. In the first variation, with food or a toy as a reward, when dogs checked they were correct more often than when they did not check. However, in the second variation, with high-value or low-value food as the reward, even when dogs checked, they were not correct more than one would expect based on chance. The researchers theorize that this could be due to inhibition problems – the dogs get so excited about finding the reward, that they cannot stop themselves from approaching the closest fence even when they have seen that the reward is probably not there.

Additionally, the dogs did check more often for the toy than for the food in the first variation, suggesting that they do show flexibility in their searching and are not just engaging in a routine behavior. However, they did not check more often for the high-value food in the second variation, although they did look for it more quickly. Overall, the researchers concluded that the dogs, while showing some degree of searching flexibility, are not as flexible as primates.

In a third variation of the test, the dogs could always see where a food reward was placed, but were subject to a delay of 5 seconds to 2 minutes before being allowed to retrieve the reward. Interestingly, the dogs did not check more often with a longer time delay, even though they were slightly less successful. “It’s possible that this was due to a ‘ceiling effect,’ as dogs overall selected the correct fence in 93% of trials in this variation, so the pressure for seeking extra information was low,” suggests Belger.

Do dogs have metacognitive abilities?

The results did not allow the researchers to say definitively whether dogs possess metacognition, although they displayed some evidence for it. “For humans, vision is an important information gathering sense. In this case our experiment was based on a ‘checking’ action relying on sight – but the dogs probably also used their sense of smell when checking through the gap. We know that smell is very important for dogs and we could see that they were using it,” states Bräuer. “In future, we would like to develop an experiment investigating under what circumstances dogs decide to use their sense of smell versus sight. This may give us additional insights into their information seeking abilities.”

Source:   Max Planck Institute for the Science of Human History