Dogs' Sociability, Owners' Neuroticism and Attachment Style to Pets as Predictors of Dog Aggression.

A dog's aggressive behavior is influenced by external and internal factors, including its psychological profile. In this study, dogs' and owners' personalities and the owners' attachment style to their dogs were identified and associated with owner-reported dog aggression towards humans and animals. Forty Slovenian owners participated with their dogs, of different breeds and aggression history, sorted into three groups (non-aggressive dogs, dogs aggressive towards humans, and dogs aggressive towards animals). The owners filled out three separate questionnaires that assessed dog aggression history towards different targets, owner's personality and degree of insecure attachment styles to dogs; namely anxious and avoidant attachment. Dog personality was characterized using a standardized dog mentality assessment test, during which the dog was exposed to nine tasks, performed outside, and dogs were scored based on behaviors they exhibited. The results indicated that dogs which were aggressive towards humans were less sociable than non-aggressive dogs and this was associated with the higher neuroticism scores of their owners. We also found that dogs which were aggressive towards strangers had owners with lower scores for anxious attachment and that dogs which were aggressive towards owners had owners with higher scores for avoidant attachment. These results imply that the psychological profiles of both a dog and its owner influence dog aggression towards humans.

The Effect of an Irregular Feeding Schedule on Equine Behavior.

We used eight horses 1 to 12 years old to investigate the influence of irregular feeding times on the behavior. The animals were housed in individual boxes, fed with hay ad libitum and barley-oat mixture at three set times; 05:00 (earlier feeding) on Thursdays, 07:00 (delayed feeding) on Saturdays and 06:00 (regular feeding) on other weekdays. Direct observations took place in 10 continuous weeks; they started 1 h prior to feeding and lasted for 2 h. Long-term behaviors (i.e. hay and concentrate consumption, resting) were recorded every 5 min, short-term behaviors (i.e. kicking, pawing the ground, comfort behavior, taking a look toward the door) were recorded continuously. Compared to the regular feeding time, horses spent less time consuming hay, more time resting and less often took a look toward the door during the earlier feeding, whereas during the delayed feeding horses more often performed pawing the ground, kicking, comfort behavior, and took a look toward the door (p < .05). Our results indicate that deviations from the regular feeding schedule affected the behavior of horses and compromised their temporal predictability.

Individual play patterns stimulated by a familiar object are group-driven.

This study investigates the dynamics of play behaviour within groups of four juvenile pigs and uses a novel clustering and statistical modelling approach to describe new details in how individuals play with a familiar object (toy rope). We examined complex state sequence data collected during a 30 min home pen play test, using the package TraMineR, where the states were defined as object play, locomotor/social play and no play. From behavioural observations, and based on the relative proportion of the different types of object play observed, each individual was later categorised as an initiator or joiner type of player. Initiators were found to be more solitary and to show more object play whereas joiners were more social and showed less object play. The majority of groups did not have an initiator type of player, yet on average they played more. Despite strong group and type of player effects, we identified three general individual play patterns. On a group level, our results demonstrate differences in how a period of playing develops, that playing with the object simultaneously occurs more often in groups than expected by chance and that the number of pigs playing together is stable over time.

Assessing positive emotional states in dogs using heart rate and heart rate variability.

Since most animal species have been recognized as sentient beings, emotional state may be a good indicator of welfare in animals. The goal of this study was to manipulate the environment of nine beagle research dogs to highlight physiological responses indicative of different emotional experiences. Stimuli were selected to be a more or a less positive food (meatball or food pellet) or social reward (familiar person or less familiar person). That all the stimuli were positive and of different reward value was confirmed in a runway motivation test. Dogs were tested individually while standing facing a display theatre where the different stimuli could be shown by lifting a shutter. The dogs approached and remained voluntarily in the test system. They were tested in four sessions (of 20s each) for each of the four stimuli. A test session consisted of four presentation phases (1st exposure to stimulus, post exposure, 2nd exposure, and access to reward). Heart rate (HR) and heart rate variability (HRV) responses were recorded during testing in the experimental room and also when lying resting in a quiet familiar room. A new method of 'stitching' short periods of HRV data together was used in the analysis. When testing different stimuli, no significant differences were observed in HR and LF:HF ratio (relative power in low frequency (LF) and the high-frequency (HF) range), implying that the sympathetic tone was activated similarly for all the stimuli and may suggest that dogs were in a state of positive arousal. A decrease of HF was associated with the meatball stimulus compared to the food pellet and the reward phase (interacting with the person or eating the food) was associated with a decrease in HF and RMSSD (root mean square of successive differences of inter-beat intervals) compared to the preceding phase (looking at the person or food). This suggests that parasympathetic deactivation is associated with a more positive emotional state in the dog. A similar reduction in HF and RMSSD was found in the test situation compared to the resting situation. This is congruent with the expected autonomic effects related to postural shift i.e. sympathetic activation and parasympathetic withdrawal, during standing versus lying, but it cannot explain the parasympathetic deactivation in response to the more positive stimuli since the dogs were always standing in the test situation. We discuss the systematic pattern of responses, which support that increased HR and LF:HF ratio are associated with emotional arousal, but add the new proposal that a combined decrease in RMSSD and HF may reflect a more positively valenced emotional state even when an individual is already in a positive psychological state.

The effect of biting tails and having tails bitten in pigs.

Tail-biting is a behavioral abnormality which compromises the welfare of pigs. The goal of this study was to characterize the tail-biting phenotype using behavior and measures of heart-rate (HR) and its variability (HRV) in pigs. Thirty pigs were categorized as tail-biters (n=10), tail-bite victims (n=10), and control pigs (n=10) based on the frequency of tail-biting behavior that they performed or received at the farm. The animals' behavioral responses were registered at the experimental facilities for 10 min during test sessions whereas physiological responses were registered for 10 min prior to (basal) and during sessions when subjected to a novel object test (NOT) and to a novel arena test (NAT). Phenotypes differed in most behaviors during the two tests and in the NOT their physiological responses suggested different regulation of vagal tone. Biters had a reduction from baseline values to values during testing for the root mean square of successive R-R intervals (RMSSD) and the high-frequency band (HF) compared to victims, whose RMSSD and HF increased from baseline to test values. In the low-frequency band (LF), an increase was shown in biters and controls while a decrease in victims. LF was found to be strongly positively correlated with HF and RMSSD in biters. During baseline, victims tended to have lower HF and significantly higher power of the low-frequency component divided by power of the high-frequency band (LF:HF ratio) compared to biters and controls. The activity of the autonomic nervous system, especially the suppression of parasympathetic tone, indicated that both victims and biters may have a dysfunctional autonomic regulation which may indicate psychological disturbance. We provide the first documentation of phenotypic differences between pigs that have performed tail-biting, have been victimized, or have not been involved in tail biting using HRV data.