Abstract: Lateralization in dogs, Canis familiaris, has been reported for paw usage and response to visual and acoustic stimuli. Surprisingly, however, no investigation of possible lateralization for the most relevant sensory domain of dogs, namely olfaction, has been carried out. Here we investigated left and right nostril use in dogs freely sniffing different emotive stimuli in unrestrained conditions. When sniffing novel nonaversive stimuli (food, lemon, vaginal secretion and cotton swab odours), dogs showed initial preferential use of the right nostril and then a shift towards use of the left nostril with repeated stimulus presentation. When sniffing arousal stimuli such as adrenaline and veterinary sweat odorants, dogs showed a consistent right nostril bias all over the series of stimulus presentations. Results suggest initial involvement of the right hemisphere in processing of novel stimuli followed by the left hemisphere taking charge of control of routine behaviour. Sustained right nostril response to arousal stimuli appears to be consistent with the idea that the sympathetic hypothalamic-pituitary-adrenal axis is mainly under the control of the right hemisphere. The implications of these findings for animal welfare are discussed.

Abstract: This paper describes how man can enter the social hierarchy of the horse by mimicking the behaviour and stance it uses to establish dominance. A herd is organised according to a dominance hierarchy established by means of ritualised conflict. Dominance relationships are formed through these confrontations: one horse gains the dominant role and others identify themselves as subordinates. This study was conducted using five females of the Haflinger breed, totally unaccustomed to human contact, from a free-range breeding farm. The study methods were based on the three elements fundamental to the equilibrium of the herd: flight, herd instinct and hierarchy. The trainer-horse relationship was established in three phases: retreat, approach and association. At the end of the training sessions, all of the horses were able to respond correctly to the trainer. These observations suggest that it is possible to manage unhandled horses without coercion by mimicking their behaviour patterns.

Abstract: We observed the behaviour of six stabled horses (stallions n = 3; geldings n = 3) in an attempt to identify behavioural measures of eating satisfaction. The horses were required to perform an operant response (pressing a button with the muzzle) in order to access a food reward in an experimental box stall. After each horse had successfully learned the experimental situation, it participated in the experimental protocol on 4 days. Horses were brought to the experimental box stall for the operant response sessions (1 h duration per session), and upon completion, they were returned to their own (home) box stalls. The number of presses for the reward was a Fixed Ratio schedule of either 3 or 12 muzzle presses (FR3, FR12) and the FR procedure for each horse was as follows: FR3 FR12 FR12 FR3 or FR12 FR3 FR3 FR12. Number of rewards obtained during each session, and behaviour and heart rate after each session were recorded for each horse. A repeated measures ANOVA showed that the number of rewards obtained in FR3 was higher than in FR12 (P < 0.05). The horses spent more time in standing-rest, (with ears rotating laterally and exhibiting a low neck position) indicating sleep, in the home box stall, after FR3 compared to FR12 treatments (P < 0.05). Mean heart rate after standing-sleep was significantly lower than mean heart rate in the home box stall (P < 0.01). These results suggest that eating satisfaction induces sleep in stabled horses, and that episodes of standing-sleep behaviour may be a useful indicator of appropriate or enhanced welfare in the horse.

Abstract: A modified spontaneous object recognition test was used to examine object recognition memory in the domestic pig. This test uses preference for a novel object over a previously encountered sample object as indicating recognition of the sample object, and no preference as indicating no recognition. Two factors hypothesized to affect object recognition are duration of exposure to the sample stimulus and delay interval before re-exposure. Both of these factors could be manipulated in a rotational object enrichment program for pigs. Reducing exposure time and increasing the delay interval before re-exposure should decrease object recognition and prolong novelty-induced object exploration. We exposed 5-week-old pigs to different sample objects in their home pens for 10 min and 2 days, respectively. We tested for object recognition memory at various delay intervals after initial exposure by placing littermate pairs in a test pen for 10 min and recording snout contact with a sample object and a completely novel object. At a 1-h delay, half the pairs were tested with the 2-day sample object; the other half received the 10-min sample object. At a 3-h delay, pairs were tested with the opposite sample object. Pairs were also tested with the 2-day sample at a 5-day delay and the 10-min sample at a 6-day delay. We predicted that pigs would show a preference for the novel versus the 2-day sample object at all three delays, but would only prefer the novel object over the 10-min sample object at the 1-h and 3-h delays. Pigs did not show novelty preference in the presence of the 10-min sample object at any delay. Novelty preference in the presence of the 2-day sample object occurred at the 3-h (P < 0.05) and 5-day delays (P < 0.001), but not the 1-h delay. The lack of novelty preference when pigs were tested with the 10-min sample object may have been due to failure to habituate to the sample object. Testing in a different location from the initial sample object exposure and retroactive interference from exposure to the 10-min sample object may have contributed to a temporary lack of novelty preference when pigs were tested with the 2-day sample object at the 1-h delay. The finding that pigs retained a memory for the 2-day sample object for at least 5 days suggests that restricting object exposure to less than 2 days may help to preserve the exploratory value of objects rotated among pens.

Abstract: Whereas mammalian mothers and young may retain long-term social affiliations in nature, the management of animals in captivity typically dictates that offspring are abruptly and permanently separated from their mothers at a relatively early age, often prior to the time of natural weaning. For animal breeders, this strategy can enhance the yield of offspring from a breeding population. Morbidity and mortality can also precipitate severance of mother-young bonds. Although it is recognized that early weaning provides nutritional challenges for the young, relatively little attention has been paid to the psychological consequences and long-term impacts of breaking the mother-young bond in non-human mammals. Furthermore, whereas great strides are being made in our understanding of the neurobiological and genetic underpinnings of social bonding, the mechanisms underlying the process of detachment following establishment of a mother-young bond remain relatively unexplored, although parallels can be drawn with processes involved in withdrawal from addictive substances. In this review, we outline mechanisms involved in social bonding. We consider the diversity in extent and duration of mother-young attachment across mammalian lineages and implications for predicting the outcome of severing ties between mothers and young at different times post-partum. We identify characteristics signalling emotional distress resulting from separation of mothers and young and discuss strategies for mitigating separation-induced distress. These include postponement of separation, ensuring high-quality maternal care of young prior to separation, providing bonded individuals with opportunities to separate voluntarily for brief periods prior to permanent separation, use of anti-suck devices prior to separation, allowing a period of partial (fence line) contact prior to full separation, providing substitutes for stimuli previously exchanged between mother and young, providing social buffers, gradual introduction to new housing arrangements, and pharmacological intervention. Areas for future research are proposed, including the use of functional neuroimaging technologies and functional genomics approaches, in combination with behavioural assessments of reinstatement motivation, individual recognition memory and long-term consequences of early separation, to shed further light on the nature of mother-young bonding and detachment in animals.