Lee Niel

Effects of Bax gene deletion on social behaviors and neural response to olfactory cues in mice.

Bax is a pro‐death protein that plays a crucial role in developmental neuronal cell death. Bax−/− mice exhibit increased neuron number and lack several neural sex differences. Here we examined the effects of Bax gene deletion on social behaviors (olfactory preference, social recognition, social approach and aggression) and the neural processing of olfactory cues. Bax deletion eliminated the normal sex difference in olfactory preference behavior. In the social recognition test, both genotypes discriminated a novel conspecific, but wild‐type males and Bax−/− animals of both sexes spent much more time than wild‐type females investigating stimulus animals. Similarly, Bax−/− mice were more sociable than wild‐type mice in a social approach test. Bax deletion had no effect on aggression in a resident/intruder paradigm where males, regardless of genotype, exhibited a shorter latency to attack. Thus, the prevention of neuronal cell death by Bax gene deletion results in greater sociability as well as the elimination of sex differences in some social behaviors. To examine olfactory processing of socially relevant cues, we counted c‐Fos‐immunoreactive (Fos‐ir) cells in several nodes of the accessory olfactory pathway after exposure to male‐soiled or control bedding. In both genotypes, exposure to male‐soiled bedding increased Fos‐ir cells in the posterodorsal medial amygdala, principal nucleus of the bed nucleus of the stria terminalis and medial preoptic nucleus (MPN), and the response in the MPN was greater in females than in males. However, a reduction in Fos‐ir cells was seen in the anteroventral periventricular nucleus of Bax−/− mice.

A systematic review and meta-analysis of the proportion of dogs surrendered for dog-related and owner-related reasons.

Companion-animal relinquishment is a worldwide phenomenon that leaves companion animals homeless. Knowing why humans make the decision to end their relationship with a companion-animal can help in our understanding of this complex societal issue and can help to develop preventive strategies. A systematic review and meta-analysis was conducted to summarize reasons why dogs are surrendered, and determine if certain study characteristics were associated with the reported proportions of reasons for surrender. Articles investigating one or more reasons for dog surrender were selected from the references of a published scoping review. Two reviewers assessed the titles and abstracts of these articles, identifying 39 relevant articles. From these, 21 articles were further excluded because of ineligible study design, insufficient data available for calculating a proportion, or no data available for dogs. Data were extracted from 18 articles and meta-analysis was conducted on articles investigating reasons for dog surrender to a shelter (n=9) or dog surrender for euthanasia (n=5). Three studies were excluded from meta-analysis because they were duplicate populations. Other reasons for excluding studies from meta-analysis were, (1) the study only investigated reasons for dog re-relinquishment (n=2) and (2) the study sample size was <10 (n=1). Two articles investigated reasons for both dog surrender to a shelter and dog surrender for euthanasia. Results of meta-analysis found owner health/illness as a reason for dog surrender to a shelter had an overall estimate of 4.6% (95% CI: 4.1%, 5.2%). For all other identified reasons for surrender there was significant variation in methodology among studies preventing further meta-analysis. Univariable meta-regression was conducted to explore sources of variation among these studies. Country was identified as a significant source of variation (p<0.01) among studies reporting behavioural problems as a reason for dog surrender for euthanasia. The overall estimate for studies from Australia was 10% (95% CI: 8.0%, 12.0%; I(2)=15.5%), compared to 16% (95% CI: 15.0%, 18.0%; I(2)=20.2%) for studies from other countries. The present systematic review and meta-analysis highlights the need for further research and standardization of data collection to improve understanding of the reasons for dog relinquishment.

Altered anxiety and defensive behaviors in Bax knockout mice.

Developmental neuronal cell death is critically regulated by the pro-death protein Bax. Bax-/- mice exhibit increased neuron number, the elimination of several neural sex differences, and altered socio-sexual behaviors. Here we examined the effects of Bax gene deletion on anxiety and defensive behaviors by comparing the responses of male and female wildtype and Bax-/- mice to two different tests. On the elevated plus maze, Bax-/- mice of both sexes made more entries into and spent more time in the outer portion of open arms, indicating decreased anxiety compared to wildtype animals. Next, we exposed mice to two odors: trimethylthiazoline (TMT), an olfactory component of fox feces that rodents find aversive, and butyric acid (BA), an aversive odor without ecological significance. Each odor was presented individually and all animals were tested with both odors in a counterbalanced design. TMT was consistently more aversive than BA across a variety of behaviors (e.g., mice spent less time close to the odor source). Overall, Bax -/- mice showed fewer stretch approaches to both TMT and BA than wildtypes, but they avoided the odor source more (e.g., fewer contacts and less time spent in proximity). Finally, no effect of genotype was seen in baseline olfactory behavior; all mice were able to locate a buried food item, demonstrating that Bax-/- mice do not have impaired olfaction per se. Collectively, these data suggest a change in strategy with anxiety and defensive behaviors in Bax-/- mice, indicating that alterations in cell number affect more general mechanisms of fear and anxiety in addition to behaviors directly related to reproduction.

Effect of Adopters' Lifestyles and Animal-Care Knowledge on Their Expectations Prior to Companion-Animal Guardianship

Human expectations can greatly affect the human–companion animal relationship, sometimes putting nonhuman animals at risk for relinquishment. At 20 animal shelters in Southern Ontario, Canada, potential adopters (N = 234) completed a questionnaire regarding their lifestyle, companion animal-care knowledge, and preadoption expectations of their adopted companion animals. Linear mixed models were used to assess the associations of adopters lifestyles and companion animal-care knowledge with their expectations for animal behavior, the human–companion animal relationship, and the effort required in companion-animal guardianship. Dog adopters had higher expectations than cat adopters for their companion animals behavior (p < .001), the human–companion animal relationship (p < .001), and the effort required in companion-animal guardianship (p < .001). Adopters human relationship statuses were also associated with expectations for the human–companion animal relationship (p = .002). As adopters companion animal-care knowledge increased, so did their expectations for the effort required in companion-animal guardianship (p < .001). An understanding of adopters expectations prior to adoption will help animal shelters better match, educate, and prepare adopters for their lives with companion animals.

Exploratory Study of Adopters’ Concerns Prior to Acquiring Dogs or Cats from Animal Shelters

Caretaker expectations for companion-animal guardianship can affect attachment to, and satisfaction with, an animal. Understanding these expectations may help match adopters and companion animals, increasing success of adoptions. Seventeen one-on-one interviews were used to gain a deep understanding of the thoughts and expectations of potential cat or dog adopters at three animal shelters in Ontario, Canada. Thematic analysis was conducted until data saturation was achieved ( n = 14). Animal behavior was the most common prior concern held by participants, specifically, unknown history, aggression, incompatibility between animals, and shy or aloof, destructive, or vocal behavior. Participants who identified adoption “deal-breakers” often identified specific traits they wanted and did not want in an animal. In contrast, others indicated they would seek out training or advice for problem behaviors. Participants discussed prior human-related concerns less frequently. Understanding pre-adoption concerns at the time of adoption will assist in better preparing individuals for companion-animal guardianship.

A survey exploring factors associated with 2890 companion-rabbit owners’ knowledge of rabbit care and the neuter status of their companion rabbit

Pet owners knowledge of pet care has been shown to affect the human-animal relationship and the welfare of companion animals. With rabbits being the third most common companion animal in many regions, and evidence of owners lack of awareness for the standards of care required to care for companion rabbits, it is important to understand the knowledge level of rabbit owners and determine how companion rabbits are being cared for. The purpose of this study was to survey rabbit owners in order to explore factors associated with their knowledge of rabbit care, and the neuter status of their companion rabbit. Current rabbit owners (n=2890) completed an online survey investigating acquisition of their companion rabbit, husbandry and care of their current rabbit, neuter status of their rabbit, owners knowledge of rabbit care and owners attachment to their current rabbit. An approximation of logistic regression modeling revealed increasing attachment (p<0.001), increasing participant age (p<0.001) and regular veterinary check-ups (p<0.001) were all associated with higher odds of answering a knowledge question correctly. Country of residence (p<0.001), where participants acquired their rabbit (p<0.001) and where they heard about the survey (p<0.001) were also found to be associated with participants level of rabbit knowledge. Logistic regression on the outcome of neuter status found increasing knowledge scores (p<0.001), regular veterinary check-ups (p<0.001) and owning only one rabbit versus multiple rabbits were associated with increased odds of currently owning a neutered rabbit. Country of residence (p<0.001) and where participants acquired their current rabbit (p<0.001) were also associated with whether participants rabbit was neutered. Though findings represent the knowledge and actions of a specific population of companion-rabbit owners, the current study suggests acquisition sources, veterinarians, and companion-animal professionals can have an important role in the development of companion-rabbit owners knowledge of rabbit care and in promoting the importance of neutering companion rabbits. Efforts to develop accessible resources to assist with educating companion-rabbit owners is important to ensuring successful rabbit-owner relationships.

Dermatophyte surveillance in cats in three animal shelters in Ontario, Canada

Objectives The aim of the study was to determine the prevalence of dermatophyte shedding in cats admitted to three Ontario animal shelters from February to May 2013. Methods Four hundred cats were sampled within 48 h of admission, using a standard toothbrush sampling technique. Dermatophyte culture was performed. Results Dermatophytes were not identified in any of the 400 cats (0–0.9% one-sided exact 97.5% confidence interval). Conclusions and relevance These results imply that dermatophyte shedding is rare in cats admitted to Ontario animal shelters. Consequently, identification of infected animals, particularly multiple animals, represents an unusual occurrence that may justify prompt and intensive control measures.

Puppy socialization practices of a sample of dog owners from across Canada and the United States

OBJECTIVE To identify actions taken by owners to socialize puppies < 20 weeks of age, to determine factors affecting attendance of structured puppy classes, and to examine associations between class attendance and owner response to various undesirable puppy behaviors. DESIGN Cross-sectional study. SAMPLE 296 puppy owners (each with 1 puppy). PROCEDURES Participants completed a survey at enrollment (to gather data regarding owner demographics and puppy characteristics) and again when puppies were 20 weeks of age (to gather information on socialization practices and owner responses to misbehavior and signs of fear in their puppy). Responses were compared between owners that did (attendees) and did not (nonattendees) report attending puppy classes. RESULTS 145 (49.0%) respondents reported attending puppy classes. Class structure differed greatly among respondents. Attendees exposed their puppies to a greater number of people and other dogs than nonattendees as well as to various noises and situations. Puppies of attendees were less likely than puppies of nonattendees to have signs of fear in response to noises such as thunder and vacuum cleaners as well as to crates. Fewer attendees reported use of punishment-based discipline techniques than did nonattendees. Almost one-third of puppies received only minimal exposure to people and dogs outside the home during the survey period. CONCLUSIONS AND CLINICAL RELEVANCE A notable number of puppies < 20 weeks of age in this study received few early socialization opportunities, which could lead to behavior problems and subsequent relinquishment. Opportunities exist for veterinarians to serve an important role in educating puppy owners about the importance of early puppy socialization and positive reward training.

Dietary fat and carbohydrate have different effects on body weight, energy expenditure, glucose homeostasis and behaviour in adult cats fed to energy requirement.

The effects of dietary carbohydrate and fat on feline health are not well understood. The effects of feeding diets moderately high in fat (HF; n 10; 30 % fat, 26 % carbohydrate as fed) or carbohydrate (HC; n 10; 11 % fat, 47 % carbohydrate), for 84 d, were investigated in healthy, adult cats (3·5 (sd 0·5) years). Data on indirect calorimetry, blood biomarkers, activity, play and cognition were collected at baseline, and at intervals throughout the study. Body composition was measured by dual-energy X-ray absorptiometry at baseline and on day 85. There were no significant main effects of diet on body weight and composition. When data were analysed over study day within diet, cats fed HF diets experienced a significant increase in body fat (P = 0·001) and body weight (P = 0·043) in contrast to cats consuming the HC diet that experienced no change in body fat or body weight (P = 0·762) throughout the study. Overall, energy expenditure was similar between diets (P = 0·356 (fasted), P = 0·086 (postprandial)) and respiratory quotient declined with exposure to the HF diet and increased with exposure to the HC diet (P < 0·001; fasted and postprandial). There was no difference in insulin sensitivity as an overall effect of diet (P = 0·266). Activity declined from baseline with exposure to both diets (HC: P = 0·002; HF: P = 0·01) but was not different between diets (P = 0·247). There was no effect of diet on play (P = 0·387) and cats consuming either the HF or HC diet did not successfully learn the cognitive test. Overall, cats adapt to dietary macronutrient content, and the implications of feeding HC and HF diets on risk for adiposity as driven by metabolic and behavioural mechanisms are discussed.

Identification of fear behaviors shown by puppies in response to nonsocial stimuli

ABSTRACT Understanding fear behavior in puppies is important for dog welfare, prevention of behavioral issues, and ensuring research assessments are accurate. Further research is necessary to determine which specific behaviors puppies show when they are fearful and whether these behaviors are similar to those seen in older dogs. We assessed which puppy behaviors are associated with mild‐ to‐ moderate fear in the presence of social and nonsocial stimuli. However, no puppies showed fear responses toward social stimuli, so only results for nonsocial stimuli are presented. Puppies (<6 months; n = 25) were introduced into a 3.7‐ m long run and trained to approach the far end to obtain a food reward. After training, each puppy completed 4 trials with noisy or unpredictable novel objects (nonsocial stimuli), 2 trials with strangers (social stimuli), and 6 control trials with no stimuli. All sessions were video‐recorded, and frequencies and durations of behaviors performed during each nonsocial stimuli trial, and the immediately preceding blank control trial, were recorded (n = 193). For each trial, the puppys behavioral response was categorized as “fearful” if the latency to approach was greater than the mean + 2 standard deviations of the blank control trials. Linear, logistic, and Poisson mixed models, with puppy as a random effect, were used to model behavior durations, presence of behavior (yes/no), and counts of how many times the puppy performed the behavior in a given trial, respectively. The following behaviors occurred more in trials with a “fearful” response in comparison to blank control trials: lowered posture (P < 0.001), lowered tail (P = 0.001), freezing (P < 0.001), retreating (P < 0.001), flinching (P < 0.001), paw lift (P = 0.006), and barking (P = 0.002). Sniffing (P < 0.001), locomotion (P < 0.001), and panting (P < 0.001) occurred less in trials with a “fearful” response. No significant difference was found for ear position, lip licking, and tail wagging. Yawning, shaking, elimination, whining, and growling occurred too infrequently for analysis. These results indicate that postural, retreating, and barking behaviors are the most reliable indicators of mild‐ to‐ moderate fear in puppies in situations where they are able to control their approach to nonsocial stimuli intended to elicit fear.