Search

The rearing environment of layer chicks can differ greatly in degree of complexity. With the industry moving towards cage-free housing systems, greater demands are placed on the birds’ cognitive abilities in order for them to find resources such as food, water and nest-boxes. Because early environmental complexity can influence cognition, we aimed at increasing our knowledge of how two different rearing environments affect the cognitive abilities of the hens. We habituated 64 hens to a spatial holeboard test, half of which were reared in cages and the other half in an aviary. Out of these 64 hens, 14 cage- and 14 aviary-reared White Leghorn hens were tested twice a day every workday in a holeboard test from 32 to 40 weeks of age. The test consisted of 4 consecutive phases, namely the uncued, cued, over-training and reversal phases, during which the hens had to find baits in a subset of cups in an arena. All cups were identical, so hens had to rely on spatial cues to find the baits which were always hidden in the same cups. During the cued phase, cues were added to the baited cups to give additional information to the hens. During the reversal phase, baits were hidden in a new subset of cups to study cognitive flexibility. The results show the birds were able to successfully complete the task. Aviary-reared hens had a higher reference memory score than cage-reared hens in the first block of the cued phase (F1,26= 4.21, p1,26= 5.26, p1,26= 6.32, p1,26= 6.29, p1,26= 6.19, p1,26= 5.87, p&nbsp

Poor health is associated with an increased risk of tail biting outbreaks in pigs. We propose that this is because illness changes social dynamics either by changing the behaviour of the sick pig towards its penmates, the behaviour of the healthy penmates towards the sick pig, or both. We tested the effect of immune stimulation (lipopolysaccharide (LPS) injection: O111:B4; 1.5 mu g kg(-1) IV) on social behaviour in gilts housed in triplets in a cross-over experiment. Each pen was subjected to the control treatment (all three pigs injected with saline) and then LPS treatment (one pig injected with LPS, two injected with saline), or vice versa. LPS injected pigs had a shift in social motivation and performed more tail- and ear- directed behaviour than saline pigs two days after injection. They seemed to fit the description of 'sick and grumpy'. This change was seen about 40 h after the signs of acute illness dissipated and was not accompanied by a similar increase in activity. We discuss possible mechanisms for this behavioural change in light of changes in neurotransmitter levels at three days after LPS injection described in a previous experiment.

Tail biting is detrimental to animal welfare and has negative consequences for producer economy. Poor health is one of the risk factors for tail biting. The first aim of this study was therefore to test for links between health status and behavior related to tail biting at the individual level. The second aim of this study was to test whether variation in cytokines was related to variation in social behavior. These small molecules produced upon immune activation are known to influence behavior both in the direction of withdrawal and increased aggression. This could potentially increase non-functional social behavior and thereby the risk of a tail biting outbreak. To investigate this, we collected behavioral data, health data, feeding data and blood samples from undocked boars at a test station farm in Norway. We compared groups with three different diagnoses: osteochondrosis diagnosed by computer tomography scanning (OCSAN), osteochondrosis diagnosed by clinical examination (OCCLIN) and respiratory tract disease (RESP), with healthy controls (CTR). We tested whether the diagnoses were associated with feeding and growth, social behavior and cytokine levels. We then tested whether there were correlations between cytokine levels and social behavior. We also provide raw data on cytokine levels in the extended sample (N = 305) as there are few publications on cytokine levels measured in pigs living under commercial conditions. OCCLIN pigs visited the feeder less, and fed longer compared to CTR pigs. Pigs diagnosed with RESP showed a large drop in growth the first week after filming, which corresponds to the week they were likely to have been diagnosed with illness, and a tendency to compensatory increase in the week after that. Social behavior differed between experimental groups with OCSCAN pigs receiving more social behavior (both aggressive and non aggressive) compared to CTR, and RESP pigs tending to perform more ear- and tail-biting than controls. There were no differences in absolute levels of cytokines between categories. However IL1-ra and IL-12 showed correlations with several behaviors that have been shown by others to be associated with current or future tail biting activity. To our knowledge, this is the first published study indicating a role for illness in non-functional social behavior in pigs and the first showing a correlation between cytokine levels and social behavior.

Studies using classical conditioning have shown that hens display high frequencies of dopamine-controlled cue-induced anticipatory behaviours in the cue-reward interval when signalling mealworm rewards. However, it is not known whether anticipatory behaviours are reward specific, and whether the opioid system is involved in their control. The purpose of the present study was to investigate (1) effect of incentive value of rewards, and (2) the involvement of μ-opioid receptor activation, on the expression of cue-induced anticipatory behaviours in laying hens. Incentive value was manipulated by reward type (mealworm and whole wheat) and by physiological state (sated and fasted hens). Hens ( n =14) were trained to associate a cue (green or red light) with a reward (whole wheat or mealworms). Blue light served as an unrewarded control stimulus. Cue-induced anticipatory head movements (latency to first head movement after cue presentation, and frequency of head movements in the cue-reward interval), steps (frequency), and pecking at reward (latency), were registered in sated and fasted hens during a 25s cue-reward interval. An involvement of the opioid system in mediating cue-induced anticipatory behaviours was tested by intraperitoneal injection of the μ-opioid receptor antagonist naloxone at 5.0mgkg −1 . Saline served as control. Injections were administered 30min before the light cues. Individual hens were tested on all treatment combinations: sated/saline, fasted/saline, sated/naloxone, and fasted/naloxone. Incentive value of signalled reward was differentially reflected by the frequency of cue-induced head movements ( P P P =0.0003, respectively), but there was no difference between the rewarded cues. Latency to initiate the first head movement was longer in response to the unrewarded cue than to cues signalling whole wheat and mealworms ( P =0.051 (tendency) and P =0.0017). Hunger amplified the frequency of head movements ( P P

Granulomatous peritonitis is often induced by intraperitoneal vaccination in fish. Peritonitis is a very painful condition in mammals, but little is known about how fish experience this condition. In a previous experiment we found increased latency to eat and a tendency to decreased swimming during feeding in vaccinated salmon housed in groups of three. These changes in behaviour correlated with the severity of the peritonitis. However, dominance relationships may influence the degree of pain-related changes in behaviour and physiology shown by group-housed fish, and we therefore conducted the present study using singly-housed fish. The aim was to describe changes in latency to eat, hiding, swimming and bottom behaviour after vaccination, to test whether morphine would alleviate changes in behaviour, and finally to test whether vaccination and/or morphine would influence the response of the fish in the novel object test. In addition, we looked for microscopic changes of peritonitis two days after vaccination to test whether we would be able to detect inflammation at an early stage. Four treatment groups were used: VS (injected with vaccine intraperitoneally (ip) and saline intramuscularly (im)), VM (injected with vaccine ip and 300 mg kg −1 morphine im), SS (saline ip, saline im) and SM (saline ip, morphine 300 mg kg −1 im). Swimming during feeding decreased in the VS fish 2 days after treatment, both compared to baseline ( p = 0.031) and to the SS group ( p = 0.023). The latency to eat differed significantly between groups at 6.5 h after treatment ( p = 0.027), and showed a tendency towards a difference 2 days after treatment ( p = 0.092). The VS group showed significantly higher latency to eat compared with the saline group 6.5 h and 2 days after treatment ( p = 0.024 and 0.043, respectively). Contrary to predictions, we did not find an increase in bottom behaviour after vaccination. We could not detect any microscopic signs of peritonitis 48 h after vaccination. Morphine did not seem to have an analgesic effect in that there were no differences between the VM and VS groups. However, the SM fish spent significantly more time in the open during the novel object test compared with the SS fish ( χ 2 = 6.97, df = 1, p = 0.0083) one day after injection, indicating an anxiolytic effect of morphine at that time-point. It is important that the lack of analgesic effect is not taken to indicate lack of pain perception in salmon. Inter species differences in analgesic efficacy is well known in veterinary medicine, and the results from this paper indicate that we need to look at alternatives to morphine to find effective analgesics for Atlantic salmon.

In order to understand the impact of different experimental and husbandry procedures on fish, and ensure that the behavioural and physiological needs of fish used in research are met, it is necessary to have detailed knowledge of their behaviour. This knowledge is largely lacking for Atlantic salmon. Results from behavioural studies of rainbow trout are often extrapolated to Atlantic salmon even though this may not be correct. Pre-smolt Atlantic salmon show diurnal variation in behaviour in the wild, but there are no published descriptions of behaviour during the dark hours for salmon held in the laboratory. Thus, the first aim of this paper was to describe the time budget of singly-held salmon both during the light and dark hours on the first and seventh day after introduction to a new environment. Statistical differences in time budget between morning, afternoon and night are described. In addition, three environmental enrichments were provided, and the time spent using each resource was scored. In general, no behaviours differed in frequency between morning and afternoon registrations, but there were significant differences in the time-budget between day and night and also between day 1 and 7. Fish hid less and displayed more behaviours during the night than during the day, and also after 7 days in the tank compared to at the first day. The exceptions were bottom behaviours which were displayed with the same frequency during day and night and during day 1 and day 7, and hovering, which was unchanged at night from day 1 to day 7. Thus, different behaviours seem to be influenced by light and by the novelty of the surroundings to different degrees. Of the three enrichments included in the study, the hiding place and the inlet current were used most frequently. As far as the authors know, this is the first paper describing the daytime and night time behaviour of parr Atlantic salmon in a research facility in detail.

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.

Positive affective states may be as important for animal welfare as the absence of suffering. Thus, there is a need for knowledge of the mechanisms underlying positive affective states, including how they can be induced and assessed. Studies of behaviour during the anticipation of a signalled palatable food reward have been suggested as a promising tool for answering these questions for the following three reasons: Anticipatory behaviour is hypothesized to reflect an appetitive type of positive affective state associated with dopaminergic activity in the brain. Inducing anticipation is useful for inducing pleasure and reducing stress. Finally, anticipatory behaviour can be used to test a subject's sensitivity to reward. However, to test various hypotheses regarding anticipatory behaviour there is a need to develop standardized research protocols. The aim of the present study was to develop and test an automated method for studying anticipatory and consummatory behaviour in laying hens in their home environment based on trace conditioning. Experimental hens (EX) were first trained to acquire the association between CS (conditioned stimulus; a green light) and US (unconditioned stimulus; meal worm) using a trace interval of 3.5s. To test if EX hens had formed an association between CS and US, they were exposed to CS alone. Then, EX hens were trained to anticipate by gradually increasing the CS–US interval from the initial 3.5s trace interval with a 1s increment on every other CS+US presentation up to 22s after 3 days and 32s after 5 days of training. Finally, they were tested using a CS–US interval of 22 and 32s. Control hens (CO) were exposed to CS and US in a random order, and tested as described for the EX hens. The results demonstrated that the EX hens responded to the CS with an increased level of anticipatory behaviour compared to the CO hens, and that this difference between the groups was significant at a CS–US interval of 22s. No differences between treatments were found in any of the consummatory behaviours. In conclusion, trace classical conditioning can be used for inducing anticipatory behaviour in ad libitum fed laying hens freely moving in the home pen environment. This method will facilitate the testing of hypotheses about reward-related behaviour in laying hens.

The question of whether fish can perceive pain is controversial, and pain is a potentially grave threat to fish welfare. To be able to study pain in a species, knowledge of its nociceptive system is necessary. There is therefore a need for standardised, repeatable and quantifiable measures of nociception and pain in fish. Sensitivity to noxious heat is readily quantifiable. We developed an apparatus to expose goldfish to controlled, localised heat stimulation, and tested the hypothesis that goldfish perceive heat as aversive. We predicted that they would respond to increasing heat with an escape response, that morphine would decrease their heat sensitivity and that the heat stimulation would affect post-test behaviour. A safety cut-off temperature of 50 8C was built into the test apparatus. All 16 fish responded to the heat with an escape response, with a mean baseline of 38 8C. However, morphine at 40 and 50 mg kg

The young of precocial species such as the domestic chicken can, shortly after hatching, imprint on a visually conspicuous object. The chicks' filial behaviour is influenced by a predisposition, directing its attention towards conspecifics, and a learning process, allowing it to distinguish between individuals. The concentrations of maternally derived steroid hormones found in birds' eggs depend on environmental factors and may be how the hen influences her progeny's behavioural development. We tested the hypothesis that prenatal exposure to corticosterone affects filial behaviour in the chick. Eggs in the treatment group were injected with corticosterone before incubation; eggs in the control treatment were vehicle-injected. In experiment 1, coloured chicks were used as imprinting stimuli and subjects were tested in a simultaneous discrimination test. Control chicks showed a significant preference for the imprinting stimulus, but treatment chicks did not. There was no difference between groups in preference scores, which measured memory of the imprinting stimulus. However, colour affected preference score differently between groups. Treatment chicks spent more time with stimulus chicks, regardless of colour, than did control chicks, indicating that corticosterone increased the strength of the predisposition. In experiment 2, chicks were imprinted on objects and tested in a sequential discrimination test. The results indicated a tendency for discrimination in the control group but no discrimination in the treatment group. No difference in preference score between control and treatment chicks was found.