Behavioural changes and aversive conditioning in hunting dogs by the second-year confrontation with domestic sheep

Domesticated dogs occasionally exhibit predatory behaviour towards domestic sheep when running loose in pasture. Both young and old dogs of either sex may chase sheep. Electronic dog collars applying electric shocks are utilised as one method of training dogs to refrain from attacking sheep. This device is used for a number of other training purposes which have raised concern for the welfare of the dogs being trained. This study aims at testing long-term learning effects of previous sheep tests on sheep chasing in hunting dog breeds (Norwegian elkhounds (grey), English setters, and hare hunting dogs), in particular with use of electronic dog collars, in addition to uncovering potential secondary negative effects on dogs' behaviour and mental stability. The dogs (N=114) were subjected to three tests for two subsequent years, the second year being reported here. Dogs were tested for reactions to different stimuli, including a sheep, in a path test. In a sheep confrontation test, dogs were fenced in with a sheep group and given el. shocks when approaching 1-2m from sheep. A questionnaire to the dog owners reported differences in dogs' behaviour between the years.Dogs showed weaker or delayed behavioural responses in both tests in the second year. No dogs showed interest in or attacked a lone sheep in the path test in the second year, while almost two thirds of them did so the first year. In the sheep confrontation test, the dogs exhibited comparatively hesitant initial hunting motivation the second year, being more evident in dogs which received el. shocks the first year. No dogs chased or attacked sheep as their first response in this test, while half of them did so the first year. The proportion of dogs attacking sheep during the entire test was reduced to almost one fourth. The number of el. shocks administered reduced by the second year, and only one of the dogs that received el. shocks the first year received el. shocks the second year. The owners reported no negative effect on the dogs' behaviour during the year ensuing el. shock treatment. Eighteen of the 24 dogs reported by owners to exhibit behavioural changes lost their previous interest in sheep.The second-year tests indicate that aversive conditioning with the use of electronic dog collar may be an efficient method for reducing the probability of a dog chasing or attacking grazing sheep. No adverse effects were observed with our test procedure.     

Social facilitation of predatory, sheep-chasing behaviour in Norwegian Elkhounds, grey

Sheep grazing on unfenced mountain pasture may be attacked by loose dogs, which may chase and kill sheep and separate lambs from their mothers. We have earlier shown that testing dogs individually towards sheep with an electronic dog collar may effectively reduce the chasing propensity 1 year later. The aim of this study was to investigate whether and how a non-chasing and a chasing companion dog influence sheep chasing in test dogs (20 Norwegian Elkhounds, grey), and whether this varies with sex or age. The test dogs' predatory behaviour towards sheep was examined by observation of the dogs in a fenced enclosure with sheep in 5min tests together with, first, a non-chasing (Hamilton stoever, a hound breed) and 2-3 days later a chasing (Border collie) companion dog. Physical contact with sheep was prevented. Initially, the test dogs exhibited a higher chasing motivation towards sheep in tests with a chasing, as compared with a non-chasing, companion (P<0.001). During the entire test, 60% of the dogs attacked sheep when accompanied by the non-chaser. All dogs attacked sheep when the chasing companion was present (P=0.008), although in only 8 of 20 cases the companion dog chased simultaneously with the test dog. In the chasing-companion tests, the attack latency was shorter (P<0.001) than in tests with a non-chasing companion. The attack severity was higher when attacking alone than when attacking together with the chasing companion (P=0.033). In these tests, the higher the attack severity, the shorter was the attack latency (P=0.006). A sequence analysis on chasing-companion tests showed that test dogs generally started with observing or showing interest in sheep, followed by attacks, which increased in severity. No sex differences were observed. In non-chasing companion tests, dogs aged up to 2.5 years exhibited a weaker initial hunting motivation than older dogs (P=0.025), but during the entire test were more inclined to attack (P=0.019). Taken together, our findings indicate that a companion dog showing intentions of predatory behaviour stimulates predatory chase in another dog, while a non-chasing companion has a limited influence on this. In tests certifying dogs for their refrainment of chasing sheep, well trained Border collies approaching sheep on command might be used to reveal the full predatory potential of the dog being tested.     

Genetic and environmental factors affecting the suitability of dogs as Guide Dogs for the Blind

Summary Many dogs are found to be unsuitable for training as guide dogs for the blind. Consequently the Royal Guide Dogs for the Blind Association of Australia has embarked on a breeding program to produce a strain of labrador dogs which is suitable for guide dog training.The most common reasons for rejecting dogs are fearfulness, dog distraction, excitability, health and physical reasons and hip dysplasia. The selection program seems to have been successful in improving the success rate mainly by lowering fearfulness, but there has not been a continuing improvement. This is probably due to continual introduction of dogs from other populations into the breeding program.Males suffer from a higher rejection rate due to dog distraction and a lower rejection rate due to fearfulness and excitability than females, so that there is little sex difference in overall success rate.The heritability of success (0.44) is high enough to predict further progress from selection, again mainly against fearfulness.Variation in environment prior to 6 weeks of age, in age when dogs were placed into a private home and in age when males were castrated, had little effect on the success rate.     

The relationship of fearfulness to,and the effects of,sex, age and experience on exploration and activity in dogs

The correlations between measures of activity in different situations, including inhibitory training, were positive but low. Activity in non-stressful situations was independent of fearfulness. There appears to be individual variation between dogs which determines whether a dog responds to fear by increasing or decreasing activity. Fearfulness was correlated with high visual and auditory exploration. General fearfulness was uncorrelated with olfactory exploration, but lack of experience in crowded, noisy places increased both olfactory exploration and fear of certain objects likely to be encountered in such places, and so caused a correlation between these two traits. Dogs which were reared in a home with another dog were less distracted by other dogs. Between 6 and 12 months, the dogs declined in activity and unwanted exploration. Females showed a higher level of activity during inhibitory training and a higher level of olfactory exploration than males.     

Foraging costs,hunting success and its implications for African wild dog (Lycaon pictus) conservation inside and outside a protected area

When selecting a habitat, animals utilize habitat in which they yield the highest rate of energy. Differences in foraging costs and hunting success are therefore likely to affect habitat choice. In a previous study, we showed that African wild dog (Lycaon pictus) packs with territories inside Hwange National Park (HNP), over the course of several years, moved their territories into the buffer zone outside HNP, where reproductive success was higher but anthropogenic mortality exceeded natality. In this study, based on long‐term radio‐telemetry data from 22 African wild dog packs, we analysed whether differences in foraging costs and hunting success could have contributed to this territorial drift. Taking seasonality and pack size into account, we determined foraging costs (foraging distance and chase distance) and hunting success (successful or failed chase) inside and outside HNP. Although we observed no difference in foraging costs, hunting success was higher outside HNP, which is likely to have contributed to the territorial drift into the buffer zone outside the protected area. This study shows the importance of taking factors affecting hunting success into account in the conservation strategy of African wild dogs.     

Contribution of dogs to white-tailed deer hunting success

Dogs (Canis familiaris) are used in hunting white-tailed deer (Odocoileus virginianus) in 10 North American jurisdictions. Although the practice is longstanding and controversial, the effects of dogs on the outcome of the hunt have rarely been studied. We evaluated the influence of dogs on recreational hunting of white-tailed deer based on long-term data from southeastern Ontario, Canada. Over 25 years, annual surveys of hunters were used to collect data on hunting effort and deer harvest from approximately 85 camps, roughly half of which had dogs. We investigated the relationship between harvest and 3 treatments (i.e., 0 dogs, 1 dog, and ≥2 dogs in camp), interactions with weather and deer density, and effects of neighboring camps. Dogs enhanced hunter success. We found no difference in deer encounter rates but, per unit effort, camps with ≥2 dogs harvested 0.013 (26%) more deer per hunter-day, missed 0.010 (23%) more deer per hunter-day, and wounded 0.002 (40%) more deer per hunter-day than camps without dogs. Conversely, camps without dogs saw, without shooting at, 0.033 (23%) more deer per hunter-day than camps with ≥2 dogs. These results are consistent with the idea that hunters with dogs are less selective. Hunters with dogs harvested more fawns per unit effort, but we found no difference in the harvest rate of older female deer. More precipitation, greater wind speed, lower temperatures and greater deer density improved harvest success but had no differential effect among dog treatments. Hunter success at camps with ≥2 dogs was less when neighboring camps also had ≥2 dogs. Because antlerless deer quotas are the principal means to control populations, increasing use of hunting dogs is unlikely to have substantial effects in managing overabundant deer. © 2012 The Wildlife Society.     

Breed-typical behaviour in dogs—Historical remnants or recent constructs?

Dogs show considerable variation in morphology, genetics and behaviour caused by long periods of artificial selection. This is evident in the large number of breeds we have today. Behavioural differences among breeds have often been regarded as remnants from past selection during the breeds’ origin. However, the selection in many breeds has, during the last decades, gone through great changes, which could have influenced breed-typical behaviour. In order to investigate this, breed differences were studied using data from a standardized behavioural test from 13,097 dogs of 31 breeds from the Swedish dog population. Based on the test results, breed scores were calculated for four behavioural traits: playfulness, curiosity/fearlessness, sociability and aggressiveness. These traits have previously been found to be stable and valid, and hence regarded as personality traits in the dog. The present results suggested large differences between breeds in all of the investigated traits, even though there were within-breed variations. No relationships between breed-characteristic behaviour and function in the breeds’ origins were found. Instead, there were correlations between breed scores and current use of the breeding stocks, which suggest that selection in the recent past has affected breed-typical behaviour. The breeds’ use in dog shows, the dominating use in general, was negatively correlated with all investigated traits, both in sires and in dams. In contrast, use in Working dog trials was positively correlated with playfulness and aggressiveness in sires. Thus, these results suggest that selection for dog show use is positively correlated with social and non-social fearfulness, and negatively with playfulness, curiosity in potentially threatening situations and aggressiveness, whereas selection for Working dog use is positively correlated with playfulness and aggressiveness. Furthermore, correlation analyses show that popular breeds have higher sociability and playfulness scores than less popular breeds, suggesting that a positive attitude towards strangers is an important characteristic of a functional pet dog and desirable by dog owners. This indicates that selection towards use in dog shows may be in conflict with pet dog selection. Furthermore, these results suggest that basic dimensions of dog behaviour can be changed when selection pressure changes, and that the domestication of the dog still is in progress. A standardized behavioural test, like the one used in this study, is suggested to be highly useful as a tool in dog breeding programs.     

Prevalence of behaviour problems reported by owners of dogs purchased from an animal rescue shelter

This study examined the prevalence of behaviour problems exhibited by dogs within 4 weeks of acquisition from a rescue shelter in Northern Ireland. One thousand five hundred and forty-seven people who had purchased a dog from a rescue shelter in Northern Ireland were sent a postal questionnaire designed to collect information on the behaviours exhibited by their dog within the first month of acquisition. Five hundred and fifty-six people responded to the survey, representing a response rate of 37%. The majority of respondents (68.3%) reported that their dog exhibited a behaviour problem, the most common being fearfulness. Most of those respondents (89.7%) who returned their dog to the shelter did so because the animal exhibited behaviour that they considered undesirable. Male dogs showed more unacceptable behaviours than females, specifically inter-male aggression, sexual problems and straying tendencies. More stray dogs displayed undesirable behaviour than unwanteds, specifically straying tendencies. Puppies were less likely to exhibit unacceptable behaviours than juveniles or adults, particularly fearfulness, sexual problems and straying tendencies. More juvenile dogs showed excessive activity and excessive barking than puppies or adults. More adult dogs displayed aggression towards other dogs than juveniles or puppies. Findings indicate that dogs purchased from rescue shelters do exhibit behaviour problems that may lead to their return. The number of dogs admitted or returned to rescue shelters with behaviour problems may be reduced by raising public awareness regarding the value of behaviour therapy and introducing behaviour therapy schemes to rescue shelters.     

Interactions between Handler Well-Being and Canine Health and Behavior in Search and Rescue Teams

ABSTRACT

This study reports on three years of prospective, longitudinal data on the psychological well-being of the human handlers and the health and behavior of the search and rescue dogs deployed in New York City and Washington, DC in the aftermath of the terrorist attacks on September 11, 2001. Eighty-five human handlers (63 deployed and 22 controls) and ninetyfour dogs (66 deployed, 28 controls) were assessed at multiple time points including 6 months, 1 year, 2 years, and 3 years after the 9/11 attacks. Humans were assessed for psychological health by structured clinical interview and self-report. Dogs were assessed for physical health and behavior by veterinary records and handler report. For humans, deployment after 9/11 did indeed represent a relatively short-term risk factor for developing symptoms of depression and posttraumatic stress disorder (PTSD). By and large, however, the sample showed remarkable resilience as a whole, and overall rates of DSM-IV diagnoses were quite low. By year 3, 9/11 deployment no longer conferred any special risk. On the other hand, long-term employment in an emergency profession did emerge as a significant risk factor for symptoms of PTSD by year 3. With respect to the interaction between handler emotional well-being and canine health and behavior, we found that physical illness and/or death in the dog was prospectively associated with greater symptoms of depression in the handler. We also found that symptoms of depression and PTSD in the handlers prospectively predicted behavioral problems in the dogs over time. Separation anxiety, attachment/attention seeking, chasing, and excitability emerged in the dogs at 1 year. Behavioral problems escalated to aggression towards other dogs at year 2 and separation anxiety, aggression towards other dogs, and aggression towards strangers at year 3. Like any relationship, the partnership between a handler and his or her working dog can confer both protection—when the relationship is going well and both members are healthy—and vulnerability—when either member is physically ill or psychologically or behaviorally distressed.     

The epidemiology of dog bite injuries in Switzerland – characteristics of victims,biting dogs and circumstances

Abstract

Dogs are a potential source of several health hazards for humans. Public attention has recently focussed on dog bites, and different prevention strategies have been suggested. As few data on dog bite epidemiology are available, a prospective study was conducted in family practices (FP) and emergency departments (ED) in Switzerland. The objectives of this study were to estimate the incidence of dog bites receiving medical treatment and to identify possible risk factors. An annual dog bite incidence rate of 180/100 000 population was estimated. The highest incidence rates were found in children, young adults and dog owners. While head and neck injuries were most common (37% of FP and 45% of ED cases) amongst children and these tended to have more severe sequelae, adults' injuries most commonly involved the extremities. Victim–dog interactions prior to the incident often were observed in children, particularly in infants (82% of 0–4-year-old cases) and in family dog bites (88%). Biting dogs were most commonly medium or large in size, male, and aged < 5 years. The three most popular breeds (Shepherd, Retriever Dogs and Swiss Mountain Breeds) also were the three most common biters. However, Shepherd dogs and Rottweilers were more common among biting dogs. No difference in bite risk was found between pure-bred and cross-bred dogs. Results of this study suggest that dog bites are a common event in the community. A multifactorial approach to dog bite prevention is recommended.     

Laser chasing behaviour of wild fishes exploited as a tool to compare space use between size,sex and species

The spatial extent of animal movement is a key consideration when designing conservation measures, such as marine protected areas. Methods to assess territory size in the marine environment, however, are labour intensive and/or expensive. Here, we explore a novel method to investigate the spatial ecology of territorial fishes by examining their reactions to an artificial light stimulus. During benthic towed video surveys conducted in Lyme Bay, southwest England, several species of wrasse (Labridae) have frequently been observed pursuing a laser projected onto the seabed. While the motivation behind ‘laser‐chasing’ is unclear, we quantified the spatial aspects of this behaviour by comparing chase distance and chase likelihood between and within species, to determine the potential utility of this method for investigating space use and aggression in wild fishes. Cuckoo wrasse (Labrus mixtus) were significantly more likely to display agonistic behaviour towards the laser than Goldsinny wrasse (Ctenolabrus rupestris). Goldsinny wrasse displayed a positive relationship between total length and chase‐distance, but not Cuckoo wrasse. The observed species differences may relate to behavioural factors affecting the motivation behind ‘laser‐chasing’, which is discussed. Chases by the cuckoo wrasse were significantly longer than those by Goldsinny wrasse, and these chase distances were used to estimate theoretical territory sizes for each species. To our knowledge, this is the first study to explore the spatial aspects of the reactions to an artificial stimulus by wild fishes. The potential to develop the method to directly investigate aspects of territoriality and aggression in wild fishes is discussed, including necessary further refinements and testing. Wild wrasses are increasingly exploited in Europe to provide cleaner fish for salmonid aquaculture, and we encourage the development of methods to inform spatial conservation measures for these ubiquitous and iconic species.     

Dogs and Practices of Community and Neighboring

ABSTRACT

Dogs are important facilitators of social interaction. However, little attention has been given to the specific mechanisms through which these relations proceed, or to the ways that dogs help to broker, maintain, and even disrupt social relations. This paper addresses this absence through an indepth qualitative analysis of the everyday experiences of 24 dog owning households who live in apartments in Sydney, Australia. It shows that dogs encourage people to spend more time outside, make people recognizable within their neighborhood, provide a topic of conversation, and actively solicit the attention of strangers. Dogs help make people recognizable and identifiable to others, while also creating social distance. The paper connects to broader literature on neighboring and community practice to show that community relations shaped by dogs involve practices of inclusion as well as exclusion. Exclusion provides an important motivation for new community formation.     

Global Positioning System Derived Performance Measures Are Responsive Indicators of Physical Activity,Disease and the Success of Clinical Treatments in Domestic Dogs

ObjectiveTo assess the use of Global Positioning System receiver (GPS) derived performance measures for differentiating between: 1) different outdoor activities in healthy dogs; 2) healthy dogs and those with osteoarthritis; 3) osteoarthritic dogs before and after treatment with non-steroidal anti-inflammatory analgesia.DesignProspective study.AnimalsTen healthy dogs and seven dogs with osteoarthritis of the elbow joint (OA dogs).ProcedureHealthy dogs were walked on a standard route on-lead, off-lead and subjected to playing activity (chasing a ball) whilst wearing a GPS collar. Each dog was walked for five consecutive days. Dogs with OA were subjected to a single off-lead walk whilst wearing a GPS collar, and then administered oral Carprofen analgesia daily for two weeks. OA dogs were then subjected to the same walk, again wearing a GPS collar.ResultsGPS derived measures of physical performance could differentiate between on-lead activity, off-lead activity and playing activity in healthy dogs, and between healthy dogs and OA dogs. Variation in the performance measures analysed was greater between individual dogs than for individual dogs on different days. Performance measures could differentiate healthy dogs from OA dogs. OA Dogs treated with Carprofen analgesia showed improvements in their physical performance, which returned to values indistinguishable from those of healthy dogs on nearly all the measures assessed.

Conclusions and Clinical Relevance

GPS derived measures of physical performance in dogs are objective, easy to quantify, and can be used to gauge the effects of disease and success of clinical treatments. Specific stimuli can be used to modulate physical performance beyond the self-governed boundaries that dogs will naturally express when allowed to exercise freely without stimulation.     

Cloning of a polymorphic canine genetic marker which maps to human chromosome 9

We describe the cloning of a novel canine polymorphic genetic marker which maps to human chromosome 9. The sequence is 2092 bp, 59% GC rich, and contains three GC boxes. Chemilumin-escent probing of zooblots showed evolutionary conservation. Dogs have three Bam HI alleles: 2.3 kb, 2.1 kb and 1.7 kb. Allele frequencies in 17 unrelated dogs representing 13 breeds are presented. Polymorphism for the 1.7-kb allele in beagles is common. The 2.1-kb allele is probably the ancestral allele since it is the most common and is also noted in the Cape hunting dog. Interestingly, in more than 50 dogs tested to date, the 2.3-kb allele has been found only in miniature and giant schnauzers. This points to a common origin for these two breeds.     

Long-term exposure to unpredictable and uncontrollable aversive events alters fearfulness in sheep

Numerous studies have investigated the emotional effects of various acute, potentially alarming events in animals, but little is known about how an accumulation of emotional experiences affects fearfulness. Fearfulness is a temperament trait that characterizes the propensity of an individual to be frightened by a variety of alarming events. The aim of this study was to investigate a putative alteration of fearfulness in sheep repeatedly exposed to various aversive events. Forty-eight 5-month-old female lambs were used. Over a period of 6 weeks, 24 of them (treated group) were exposed daily to various unpredictable and uncontrollable aversive events related to predatory cues, social context and negative handling that can occur under farming conditions. The other 24 lambs (control group) were housed in standard farming conditions (predictable food distribution and group handling). Fearfulness (behavioural and physiological responses) was assessed before and after the treatment period by subjecting the lambs to three standardized tests: individual exposure to suddenness and then to novelty in a test arena, and group exposure to a motionless human in the home pen. As biomarkers of stress, leukocyte counts, heart rate and cortisol concentrations were measured in the lambs in their home pens. Before the treatment, the emotional responses of the groups did not differ. After the treatment, treated lambs approached the human less often, had less contact with the novel object and vocalized more than controls in individual tests, suggesting that long-term exposure to unpredictable and uncontrollable aversive events increases subsequent fearfulness in sheep. In addition, treated lambs had lower leukocyte counts, heart rate and cortisol levels, pointing to a chronic stress state. These findings suggest that increased fearfulness may be used as a sign of chronic stress in farm animals.     

Rank atmospheres: The more‐than‐human scentspace and aesthetic of a pigdogging hunt

Pigdogging is a popular pastime in Australia, a form of recreational hunting whereby people collaborate with dogs to chase and catch wild pigs. This paper analyses the hunt as an interspecies event that unfolds through the sensual and sensory entanglements of human and nonhuman, with a particular focus on the perspectives of the hunters. The concept of ‘atmosphere’ will be employed to frame an ethnographic analysis of two facets of pigdogging. First, by hunting with a dog, humans augment their capacity to identify the presence of pigs through the canine's extraordinary sense of scent. Through this relationship, the world of scent is revealed as having atmospheric properties: an enveloping phenomenon which is known through the dog, yet also escapes the hunter's perceptual apprehension. Second, this paper will illustrate examples of how atmosphere develops through the sensual relations between human and nonhuman bodies during the hunt. An affectively charged interspecies encounter is composed and participated in by the hunter through this recreational practice, and affords the enactment of subjectivities central to an aesthetics of pigdogging. Hunting atmospheres in this paper emerge at the juncture of human and more‐than‐human bodies, perspectives and worlds.     

Communicating for conservation: circumventing conflict with communities over domestic dog ownership in north Morocco

Conservationists consider open and direct communication as best practice even when their data conflict with local beliefs. However, ensuring the effective delivery of a controversial message without overtly challenging community identity is difficult. Such a scenario needs high levels of meaningful contact and trust-building dialogue between conservationists and communities as well as innovative means of communicating controversial information. Indirect communication is one such strategy, allowing people to draw their own conclusions about controversial information. We present an example of successful indirect communication of such information in the context of a long-term Barbary macaque community conservation project in Morocco. Dogs in the area kill macaques and domestic livestock in the forest, and local shepherds believed these dogs to be feral. However, our observations identified these dogs as being owned, free-roaming village dogs rather than feral dogs. To impart this controversial information, we developed a dog health programme to communicate our findings and improve the health of domestic dogs to safeguard human and animal health. We administered rabies vaccinations to dogs in three villages and provided their owners with brightly coloured dog collars. After observing collared dogs hunting in the forest, the shepherds realised the dogs had owners. Community participation was high and we vaccinated 242 dogs achieving 60–81% vaccination coverage. An additional benefit of the activity was to successfully convey the message that the conservation team is committed to local people’s welfare as well as to Barbary macaque conservation.     

Positive Impact of Nutritional Interventions on Serum Symmetric Dimethylarginine and Creatinine Concentrations in Client-Owned Geriatric Dogs

A prospective study was conducted in client-owned geriatric dogs to evaluate the short-term effects of a test food on serum symmetric dimethylarginine (SDMA) and creatinine (Cr) concentrations. Test food contained functional lipids (fish oil), antioxidants (lipoic acid, vitamins C and E), L-carnitine, botanicals (fruits and vegetables), controlled sodium concentration, and high quality protein sources (high bioavailability and an ideal amino acid composition). Dogs (n = 210) were fed either test food or owner’s-choice foods (non-nutritionally controlled cohort). Dogs were included based on age and body weight: small (6.8 to 11.4 kg) and medium dogs (11.5 to 22.7 kg) were ≥ 9 years, whereas dogs >22.7 kg were ≥ 7 years at baseline. At baseline, all dogs had to have serum Cr concentrations within the reference interval and be free of chronic disease. Renal function biomarkers and urinalysis results at baseline, and after consuming test food or owner’s-choice foods for 3 and 6 months, were evaluated. Only dogs consuming test food showed significant decreases in serum SDMA and Cr concentrations (both P ≤ 0.05) across time. At baseline or during the 6-month feeding trial, 18 dogs (8.6%) had increased serum SDMA, but normal serum Cr, consistent with IRIS Stage 1 chronic kidney disease. This included 9 dogs fed test food and 9 dogs fed owner’s-choice foods. Compared with baseline, after feeding 9 dogs test food for 6 months, serum SDMA decreased in 8 dogs and increased in 1 dog. After feeding 9 dogs owner’s-choice foods for 6 months, serum SDMA decreased in 4 dogs and increased in 4 dogs (remained stable in 1 dog). The decreases in serum SDMA and Cr concentrations were significant (both P = 0.03) only for dogs fed test food. These results suggest that nonazotemic dogs with elevated serum SDMA (early renal insufficiency) when fed a test food designed to promote healthy aging are more likely to demonstrate improved renal function compared with dogs fed owner’s-choice foods.     

Toxigenic Corynebacterium ulcerans isolated from a hunting dog and its diphtheria toxin antibody titer

Toxigenic Corynebacterium ulcerans is a zoonotic pathogen that produces diphtheria toxin and causes a diphtheria‐like illness in humans. The organism is known to infect and circulate among dogs, which can then transmit it to humans. Furthermore, previous studies have found that C. ulcerans is carried by wild animals, including game animals. In the present study, we tested hunting and companion dogs for the presence of toxigenic C. ulcerans and succeeded in isolating the bacterium from a hunting dog. Moreover, several hunting dogs had serum diphtheria antitoxin titers that were higher than the titers required for protection in humans, suggesting a history of exposure to toxigenic Corynebacterium strains. Notably, ribotyping, pulsed‐field gel electrophoresis and tox gene sequencing demonstrated that the isolate from the hunting dog clustered with previously characterized C. ulcerans strains isolated from wild animals, as opposed to groups of isolates from humans and companion dogs. Interestingly, the wild animal cluster also contains an isolate from an outdoor breeding dog, which could have formed a bridge between isolates from wild animals and those from companion dogs. The results presented herein provide insight into the mechanism by which the zoonotic pathogen C. ulcerans circulates among wild animals, hunting and companion dogs, and humans.     

Wolf predation on moose and roe deer: chase distances and outcome of encounters

We examined chase distances of gray wolves Canis lupus Linnaeus, 1758 hunting moose Alces alces and roe deer Capreolus capreolus, and recorded details of encounters between wolves and prey on the Scandinavian Peninsula, 1997–2003. In total, 252 wolf attacks on moose and 64 attacks on roe deer were registered during 4200 km of snow tracking in 28 wolf territories. Average chase distances were 76 m for moose and 237 m for roe deer, a difference likely due to variation in body size and vigilance between prey species. A model including prey species, outcome of the attack, and snow depth explained 15–19% of the variation found in chase distances, with shorter chase distances associated with greater snow depth and with successful attacks on moose but not on roe deer. Wolf hunting success did not differ between prey species (moose 43%, roe deer 47%) but in 11% of the wolf attacks on moose at least one moose was injured but not killed, whereas no injured roe deer survived. Compared with most North American wolf studies chase distances were shorter, hunting success was greater, and fewer moose made a stand when attacked by wolves in our study. Differences in wolf encounters with moose and roe deer likely result from different anti-predator behaviour and predator-prey history between prey species.