Randi Oppermann Moe

Assessment of positive emotions in animals to improve their welfare

It is now widely accepted that good welfare is not simply the absence of negative experiences, but rather is primarily the presence of positive experiences such as pleasure. However scientific investigation of positive emotions has long been neglected. This paper addresses two main issues: first, it reviews the current state of scientific knowledge that supports the existence of positive affective states in animals and, second, it suggests possible applications of this knowledge that may enhance quality of life under animal management conditions. In the first part of the paper, recent advances in psychology and neuroscience are reviewed to provide pragmatic frameworks based on cognitive processes (such as positive anticipation, contrast and controllability) for further investigations of positive emotions in animals. Thereafter, the neurobiological bases of positive emotions are highlighted in order to identify behavioral and physiological expressions of positive experiences in animals. Monitoring both the autonomic nervous system (via heart rate and its variability) and the immune system could offer relevant tools to better assess emotional states in animals, complementary to classical adrenocortical measures. In the second part of the paper, useful strategies for enhancing positive experiences (such as physical, social and cognitive enrichment or putative genetic selection) are outlined. Then this paper emphasizes practical applications for assessing and promoting positive emotions that may help in providing animals with a better quality of life. Play, affiliative behaviors and some vocalizations appear to be the most promising convenient indicators for assessing positive experiences in laboratory and farm animals under commercial conditions.

Exploring non-invasive methods to assess pain in sheep

The aim of this study was to determine whether changes in eye temperature, measured using infrared thermography (IRT), and heart rate variability (HRV) can detect moderate levels of pain in sheep. Six ewes received the following treatments: 1) noxious ischaemic stimulus by application of a forelimb tourniquet (S), 2) noxious ischaemic stimulus and flunixin meglumine (S+F), and 3) flunixin meglumine (F). Maximum eye temperature, HRV, mechanical nociceptive threshold, blood pressure and behaviour were recorded for up to 60 min, including 15 min of baseline, 30 min during intervention and 15 min post-intervention. There was a tendency towards a decrease in the heart rate variability parameters RMSSD (the root mean square of successive R-R intervals) and SDNN (the standard deviation of all interbeat intervals) in treatment S compared to treatment F, and a significant increase in the same parameters between test day 1 and 3. A reduction in eye temperature was detected for all treatments during intervention, but no difference was found between S and F and S+N and F during intervention. The eye temperature decreased more in test day 2 and 3 compared to test day 1 during intervention. A significant reduction for both lip licking and vocalisation was observed between test day 1 and 3, and forward facing ears was the ear posture most frequently recorded in test day 1. We suggest that HRV is a sensitive, non-invasive method to assess mild to moderate pain in sheep, whereas IRT is a less sensitive method.

Effects of environmental stressors on deep body temperature and activity levels in silver fox vixens (Vulpes vulpes)

Abstract The present study was performed to investigate the effects of 14 different environmental stimuli on stress-induced hyperthermia (SIH) and levels of locomotor activity in six (three infanticidal, three non-infanticidal) 2.5-year-old silver fox vixens. The effects of contact with humans (six experiments; handling for 5 min, handling of neighbouring animal for 5 min, presence of one person for 20 s, 5 and 90 min, presence of a group of humans for 5 min), exposure to unfamiliar foxes (four experiments; presence of an unfamiliar cagemate [female, male] and an unfamiliar neighbouring animal [female, male] for 90 min), and various recorded noise stimuli (four experiments; aircraft noise [duration 15 s, 100 dB], machine noise [duration 15 s, 90 dB], firing a shotgun [duration 1 s, 90 dB], human conversation [duration 15 s, 95 dB]) played back and repeated at 20 s intervals during 5 min were tested. Deep body temperature and activity levels were monitored with surgically implanted radio telemetry devices. All registrations were made during the 90-min period after stimulus presentation. The presence of humans and other silver foxes, but not exposure to loud recorded noise, resulted in a SIH. Comparison of the SIH between the normally reproducing vixens and the previously infanticidal vixens revealed significant differences. The SIH response was most pronounced in the previously infanticidal vixens, whereas the levels of physical activity were lowest in this group. The present study indicated that important means to improve animal welfare in silver foxes should include an improvement of the general human–animal relationship and emphasises the importance of a stable social environment.

Peripheral temperature drop in response to anticipation and consumption of a signaled palatable reward in laying hens (Gallus domesticus).

The present study describes effects of anticipation and consumption of a palatable reward on comb surface temperature. The purpose was to investigate temperature responses as a potential physiological indicator of positive emotional states in laying hens. A rise in body temperature in response to stimuli predictive of or during exposure to unpleasant events has been interpreted as evidence of emotions in mammals and avians. However, this phenomenon has so far only been studied during anticipation of or exposure to negative events; i.e., emotions of a negative valence. Infrared thermography was used to record potential alterations in comb surface temperature to a conditioned cue signaling a reward (mealworms) and during reward delivery. On average, comb temperature dropped 1.5 °C (95% CI: +/-1.2 °C) after exposure to CS and consumption of reward (p~0.0014) when initial comb temperature was above 30 °C. Such temperature drop indicates a peripheral vasoconstriction and has clear resemblances to emotional fever as seen during negative emotional states. Thus, we propose that a drop in peripheral temperature reflects emotional arousal more than emotional valence. Substantial temperature responses due to diet-induced thermogenesis were found, further emphasizing a cautious interpretation of altered comb temperature in studies of animal welfare.

Effect of including whole oats into pellets on performance and plumage condition in laying hens housed in conventional and furnished cages

In an experiment including 2400 layers, a diet with 40% whole oats incorporated into 3 mm pellets (experimental diet) was compared with a complete diet, also as 3 mm pellets, but containing no whole oats (control diet). These diets were examined in conventional 3-hens cages and two furnished cage systems with 8 or 16 birds per group including nest, perches and litter. The effects of diet, rearing condition and cage system on performance, plumage condition, comb lesions and rear body wounds were studied. Furthermore, the effect of feed structure on gizzard characteristics and interactions with access to litter during rearing and laying periods were examined. The hybrids LSL and Shaver 2000 were included in the experiment. Egg production was lower (P<0.05) in furnished cages than in conventional cages. No difference in plumage condition was found between diets, but a significantly poorer plumage condition (P<0.05) was observed with increasing group size. Also, the frequencies of rear body (P<0.05) wounds increased as the group sizes increased, while no such effect was observed for comb lesions. Higher (P<0.05) feed consumption was observed in furnished cages than in the conventional, causing a corresponding increase (P<0.05) in feed conversion rate (FCR). Higher (P<0.05) FCR was observed for birds fed pellets with whole oats than the control. Whole oats also increased (P<0.05) the weight of gizzard and gizzard contents. For LSL, better (P<0.05) plumage condition was found for birds reared on a deep litter floor compared to cage rearing. It was concluded that no beneficial effect of replacing high amounts of ground oats with whole oats was observed. Genotype and rearing method may interact with housing system.

Effect of Repeated Blood Sampling on Plasma Concentrations of Cortisol and Testosterone and on Leucocyte Number in Silver Fox Vixens (Vulpes Vulpes)

Abstract It is of great importance to be able quantitatively to evaluate the stress to which captive fur animals are subjected to by various forms of management. A range of haematological and hormonal parameters have been shown to be good indicators of stress. However, blood sampling, which entails the presence of humans and handling of the animals, can itself be a stressor that influences the results of an experiment. The present study shows that a group of silver foxes (n = 7) that had been regularly blood sampled (RBS-group) for a year had higher plasma concentrations of cortisol and lower concentrations of testosterone compared with an earlier non-blood-sampled group (NBS-group) (n = 7). The RBS-group also tended to have a lower number of lymphocytes. In addition, during a series of five blood samples taken at 30 min intervals, both groups showed an increase in plasma concentrations of cortisol, whereas numbers of lymphocytes and eosinophil leucocytes decreased. Plasma testosterone concentrations decr...

Factors affecting mechanical (nociceptive) thresholds in piglets

Objective To evaluate the stability and repeatability of measures of mechanical (nociceptive) thresholds in piglets and to examine potentially confounding factors when using a hand held algometer. Study design Descriptive, prospective cohort. Animals Forty-four piglets from four litters, weighing 4.6 ± 1.0 kg (mean ± SD) at 2 weeks of age. Methods Mechanical thresholds were measured twice on each of 2 days during the first and second week of life. Data were analyzed using a repeated measures design to test the effects of behavior prior to testing, sex, week, day within week, and repetition within day. The effect of body weight and the interaction between piglet weight and behaviour were also tested. Piglet was entered into the model as a random effect as an additional test of repeatability. The effect of repeated testing was used to test the stability of measures. Pearson correlations between repeated measures were used to test the repeatability of measures. Variance component analysis was used to describe the variability in the data. Results Variance component analysis indicated that piglet explained only 17% of the variance in the data. All variables in the model (behaviour prior to testing, sex, week, day within week, repetition within day, body weight, the interaction between body weight and behaviour, piglet identity) except sex had a significant effect (p < 0.04 for all). Correlations between repeated measures increased from the first to the second week. Conclusions and Clinical relevance Repeatability was acceptable only during the second week of testing and measures changed with repeated testing and increased with increasing piglet weight, indicating that time (age) and animal body weight should be taken into account when measuring mechanical (nociceptive) thresholds in piglets. Mechanical (nociceptive) thresholds can be used both for testing the efficacy of anaesthetics and analgesics, and for assessing hyperalgesia in chronic pain states in research and clinical settings.

Effects of housing conditions during the rearing and laying period on adrenal reactivity, immune response and heterophil to lymphocyte (H/L) ratios in laying hens

This study was conducted to evaluate the effect of early rearing conditions on physiological, haematological and immunological responses relevant to adaptation and long-term stress in white Leghorn hens with intact beaks housed in furnished cages (FC) or conventional cages (CC) during the laying period. Pullets were cage reared (CR) or litter floor reared (FR). From 16 to 76 weeks of age, hens were housed in FC (eight hens per cage) or in CC (three hens per cage). As measures of long-term stress at the end of the laying period, adrenal reactivity was quantified by assessing corticosterone responses to adrenocorticotropin challenge, and immune response was assessed by measuring antibody responses after immunization with sheep red blood cells (SRBC) and keyhole limpet haemocyanin (KLH). Heterophil to lymphocyte (H/L) ratio was employed as an indicator of stress. Rearing conditions significantly affected anti-SRBC titres (P < 0.0001) and tended to affect H/L ratios (P = 0.07), with the highest values found in FR hens. Layer housing affected H/L ratio (P < 0.01); the highest ratio was found in FR birds housed in FC during the laying period. This study shows that early rearing environment affects immunological indicators that are widely used to assess stress in laying hens. However, while results on H/L ratio indicated that FR birds experienced more stress particularly when they were housed in FC during the laying period, the immune responses to SRBC in FR hens was improved, indicating the opposite. This contradiction suggests that the effects on immune response may have been associated with pathogenic load due to environmental complexity in FR and FC hens rather than stress due to rearing system or housing system per se.

Effect of indomethacin on LPS-induced fever and on hyperthermia induced by physical restraint in the silver fox (Vulpes vulpes)

Abstract 1. 1. The effects of indomethacin on LPS-induced fever, and on hyperthermia induced by physical restraint, were investigated in the silver fox ( Vulpes vulpes ). 2. 2. Base levels of deep body temperature ( T b ) in undisturbed silver foxes measured with surgically implanted transmitters was 38.6°C (±0.1). 3. 3. Rectal temperature ( T re ) five hours after treatment with LPS was 40.1°C (±0.1), indicating a febrile response. 4. 4. T re in all foxes (LPS + indomethacin: 39.5°C ± 0.1; indomethacin + vehicle: 39.2°C ± 0.1, or vehicle alone: 39.4°C ± 0.1) was elevated compared with base levels of T b . However, T re was within the range of T b in handled or physically restrained foxes (39.4°C ± 0.1 and 39.5°C ± 0.1, respectively), indicating that handling and restraint evoked a stress-induced hyperthermia (SIH). 5. 5. T re in foxes treated with LPS was significantly reduced when they were pretreated with indomethacin (39.5°C ± 0.1), and was within the range of T re of the controls, indicating an antipyretic effect of indomethacin. 6. 6. Indomethacin did not significantly attenuate the magnitude of SIH, indicating that SIH may not, or to a minor extent, be mediated by prostaglandins in silver foxes.

Anticipatory and foraging behaviors in response to palatable food reward in chickens: Effects of dopamine D2 receptor blockade and domestication

Behaviors associated with anticipation and search for palatable food may provide information about dopaminergic reward processes and positive motivational affect in animals. The overall aim was to investigate the involvement of dopamine signaling in the regulation of cue-induced anticipation and search for palatable food reward in chicken, and whether domestication has affected expression of reward-related behaviors. The specific aims were to describe effects of mealworms (palatable food for hens) and haloperidol (a dopamine D2 antagonist) on foraging behaviors and cue-induced anticipatory behaviors in Red Junglefowl (RJF; the wild ancestor of modern laying hens) and a white layer hybrid (LSL). RJF (n=26) and LSL (n=20) were initially trained on a conditioning schedule to anticipate mealworms (unconditioned stimulus; US) 25s after exposure to a red light (conditioned stimulus; CS). For the experiment, hens received haloperidol or saline injections 30 min before exposure to one CS+US combination. Behavior was registered 10 min before CS and 10 min after US (foraging behaviors), and during the CS-US interval (anticipatory behaviors). Higher frequencies of CS-induced anticipatory head movements, faster approach to rewards, and higher frequency of foraging behaviors were found in LSL compared to RJF. Haloperidol suppressed CS-induced head movements in both breeds, and the frequency of foraging behaviors after reward delivery. The results support a role of dopamine signaling in the regulation of reward processes in chickens, and suggest that domestication has changed the threshold for perceiving food incentives and/or for expressing reward-related behaviors that may be indicative of positive motivational affect in hens.