Individual housing of dairy calves is common farm practice, but has negative effects on calf welfare. A compromise between practice and welfare may be housing calves in pairs. We compared learning performances and affective states as assessed in a judgement bias task of individually housed and pair-housed calves. Twenty-two calves from each housing treatment were trained on a spatial Go/No-go task with active trial initiation to discriminate between the location of a teat-bucket signalling either reward (positive location) or non-reward (negative location). We compared the number of trials to learn the operant task (OT) for the trial initiation and to finish the subsequent discrimination task (DT). Ten pair-housed and ten individually housed calves were then tested for their responses to ambiguous stimuli positioned in-between the positive and negative locations. Housing did not affect learning speed (OT: F1,35 = 0.39, P = 0.54; DT: F1,19 = 0.15, P = 0.70), but pair-housed calves responded more positively to ambiguous cues than individually housed calves (χ21 = 6.79, P = 0.009), indicating more positive affective states. This is the first study to demonstrate that pair housing improves the affective aspect of calf welfare when compared to individual housing.
- MeSH
- bydlení zvířat * MeSH
- chování zvířat fyziologie MeSH
- farmy * MeSH
- kognice fyziologie MeSH
- novorozená zvířata MeSH
- odstavení MeSH
- pohoda zvířat normy statistika a číselné údaje MeSH
- skot MeSH
- sociální chování * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- skot MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Many studies have shown that animal vocalizations can signal individual identity and group/family membership. However, much less is known about the ontogeny of identity information-when and how this individual/group distinctiveness in vocalizations arises and how it changes during the animal's life. Recent findings suggest that even species that were thought to have limited vocal plasticity could adjust their calls to sound more similar to each other within a group. It has already been shown that sows can acoustically distinguish their own offspring from alien piglets and that litters differ in their calls. Surprisingly, individual identity in piglet calls has not been reported yet. In this paper, this gap is filled, and it is shown that there is information about piglet identity. Information about litter identity is confirmed as well. Individual identity increased with age, but litter vocal identity did not increase with age. The results were robust as a similar pattern was apparent in two situations differing in arousal: isolation and back-test. This paper argues that, in piglets, increased individual discrimination results from the rapid growth of piglets, which is likely to be associated with growth and diversification of the vocal tract rather than from social effects and vocal plasticity.
- MeSH
- akustika MeSH
- individualita * MeSH
- kojená zvířata MeSH
- novorozená zvířata MeSH
- počítačové zpracování signálu MeSH
- skupinové procesy * MeSH
- Sus scrofa klasifikace psychologie MeSH
- velikost vrhu MeSH
- vokalizace zvířat * klasifikace MeSH
- zvířata MeSH
- zvuková spektrografie MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This study tested whether emotional contagion occurs when piglets directly observe a penmate in distress (restraint) and whether there is an effect of previous experience on the response to subsequent restraint or exposure to conspecific distress. Piglets (49.7 ± 0.7 days) were exposed in pairs to two stress phases (SP1 and SP2) in an arena divided into two pens by a wire mesh wall. During SP1, one of the pigs of a pair was either restrained (Stress treatment) or sham-restrained (Control treatment), while the other pig was considered observer. During SP2, the previous observer was restrained, while its penmate took the observer role. Heart rate variability, locomotion, vocalizations, body/head/ear and tail postures were monitored. During SP1, observer pigs responded to conspecific distress with increased indicators of attention (looking at, proximity to and snout contacts with the distressed pigs) and increased indicators of fear (reduced locomotion, increased freezing). During SP2, the observer pigs that had been restrained previously reacted more strongly (through higher proximity, decreased locomotion, increased freezing) to observing the penmate in restraint than pigs without the previous negative experience. This study suggests that young pigs are susceptible to emotional contagion and that this contagion is potentiated by previous exposure to the same stressor. These findings have implications for pig welfare in practical animal husbandry systems.
- MeSH
- emoce fyziologie MeSH
- empatie MeSH
- lokomoce MeSH
- postura těla MeSH
- psychický stres patofyziologie MeSH
- srdeční frekvence fyziologie MeSH
- Sus scrofa fyziologie MeSH
- vokalizace zvířat MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Humans as well as many animal species reveal their emotional state in their voice. Vocal features show strikingly similar correlation patterns with emotional states across mammalian species, suggesting that the vocal expression of emotion follows highly conserved signalling rules. To fully understand the principles of emotional signalling in mammals it is, however, necessary to also account for any inconsistencies in the way that they are acoustically encoded. Here we investigate whether the expression of emotions differs between call types produced by the same species. We compare the acoustic structure of two common piglet calls-the scream (a distress call) and the grunt (a contact call)-across three levels of arousal in a negative situation. We find that while the central frequency of calls increases with arousal in both call types, the amplitude and tonal quality (harmonic-to-noise ratio) show contrasting patterns: as arousal increased, the intensity also increased in screams, but not in grunts, while the harmonicity increased in screams but decreased in grunts. Our results suggest that the expression of arousal depends on the function and acoustic specificity of the call type. The fact that more vocal features varied with arousal in scream calls than in grunts is consistent with the idea that distress calls have evolved to convey information about emotional arousal.
- MeSH
- arousal fyziologie MeSH
- emoce fyziologie MeSH
- prasata fyziologie MeSH
- vokalizace zvířat fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Preverbal infants often vocalize in emotionally loaded situations, yet the communicative potential of these vocalizations is not well understood. The aim of our study was to assess how accurately adult listeners extract information about the eliciting situation from infant preverbal vocalizations. Vocalizations of 19 infants aged 5-10 months were recorded in 3 negative (Pain, Isolation, Demand for Food) and 3 positive (Play, Reunion, After Feeding) situations. The recordings were later rated by 333 adult listeners on the scales of emotional valence and intensity. Subsequently, the listeners assigned the eliciting situations in a forced choice task. Listeners were almost perfectly able to discriminate whether a recording came from a negative or a positive situation. Their discrimination may have been based on perceived valence as they consistently assigned higher valence when listening to positive, and lower valence when listening to negative, recordings. Ability to identify the particular situation within the negative or positive realm was substantially weaker, with only three of the six situations being discriminated above chance. The best discriminated situation, Play, was associated with high perceived intensity. The weak qualitative discrimination of negative situations seemed to be based on graded perception of negative recordings, from the most intense and unpleasant (assigned to Pain) to the least intense and least unpleasant (assigned to Demand for Food). Parenthood and younger age, but not gender of listeners, had weak positive effects on the accuracy of judgments. Our results indicate that adults almost flawlessly distinguish positive and negative infant sounds, but are rather inaccurate regarding identification of the specific needs of the infant and may normally employ other sensory channels to gain this information.
- MeSH
- bolest MeSH
- dospělí MeSH
- emoce * MeSH
- kojenec MeSH
- komunikace * MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- pochopení MeSH
- průzkumy a dotazníky MeSH
- senioři MeSH
- sluchová percepce MeSH
- stravovací zvyklosti MeSH
- verbální chování * MeSH
- zvuk MeSH
- Check Tag
- dospělí MeSH
- kojenec MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This study examined whether piglet distress vocalizations vary with age, body weight and health status, according to the predictions of the honest signalling of need evolutionary model. Vocalizations were recorded during manual squeezing (a simulation of being crushed by mother sow) and during isolation on Days 1 and 7 after birth in piglets from 15 litters. We predicted that during squeezing, younger, lighter and sick piglets would call more intensely because they are in higher risk of dying during crushing and therefore they benefit more from the sow's reaction to intensive vocalization. For isolation, we predicted that lighter and younger piglets would call more because they are more vulnerable to adverse effects of the separation. Calls were analyzed in their time and frequency domain. The rate of calling, call duration, proportion of high-pitched calls and eight acoustic parameters characterizing frequency distribution and tonality were used as indicators of acoustic signalling intensity. Piglets that experienced "squeezing" on Day 1 produced more intense acoustic distress signalling than on Day 7. Lighter piglets called more during squeezing than heavier piglets. Health status did not significantly affect any of the indicators of intensity of vocalization during squeezing. In isolation, none of the parameters of vocalization intensity were affected either by the age or by the weight of the piglets. In summary, the model of honest signalling of need was confirmed in the squeezed situation, but not in the isolation situation.
Two important questions in bioacoustics are whether vocal repertoires of animals are graded or discrete and how the vocal expressions are linked to the context of emission. Here we address these questions in an ungulate species. The vocal repertoire of young domestic pigs, Sus scrofa, was quantitatively described based on 1513 calls recorded in 11 situations. We described the acoustic quality of calls with 8 acoustic parameters. Based on these parameters, the k-means clustering method showed a possibility to distinguish either two or five clusters although the call types are rather blurred than strictly discrete. The division of the vocal repertoire of piglets into two call types has previously been used in many experimental studies into pig acoustic communication and the five call types correspond well to previously published partial repertoires in specific situations. Clear links exist between the type of situation, its putative valence, and the vocal expression in that situation. These links can be described adequately both with a set of quantitative acoustic variables and through categorisation into call types. The information about the situation of emission of the calls is encoded through five call types almost as accurately as through the full quantitative description.
- MeSH
- akustika MeSH
- novorozená zvířata MeSH
- Sus scrofa MeSH
- vokalizace zvířat * MeSH
- zvířata MeSH
- zvuková spektrografie MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Interspecific communication between humans and pets is possible through vocal cues. We studied how humans with differing experience with domestic pigs (Sus scrofa) interpret pig vocalizations. Forty-eight ethologists studying pigs, 31 pig-caretakers and 54 naive students evaluated the emotional intensity and valence (negative/positive) of recordings from two negative (castration, isolation) and two positive (reunion with the sow, postsuckling) contexts. They also identified the context in which the recordings were made. Castration vocalizations were evaluated as highly intense and unpleasant. The positive contexts were evaluated as low in intensity and positive in valence, and isolation fell in the middle for both intensity and valence. Compared with the other two groups, pig-caretakers evaluated the intensity of vocalizations as lower, and ethologists evaluated the valence as more negative. The level of successful classification exceeded that expected by chance for all four contexts but was especially accurate for castration. Ethologists achieved better recognition than students. Classifying (right context) and understanding the emotional content (valence, intensity) of pig vocalizations is thus a general ability of humans, although it varies according to an individual's experience with pigs.
- MeSH
- asociační učení MeSH
- diskriminační učení MeSH
- dospělí MeSH
- emoce MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- pochopení MeSH
- praxe (psychologie) MeSH
- sluchová percepce MeSH
- sociální percepce MeSH
- Sus scrofa MeSH
- vokalizace zvířat MeSH
- zvířata MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
For groups of animals to keep together, the group members have to perform switches between staying in one place and moving to another place in synchrony. However, synchronization imposes a cost on individual animals, because they have to switch from one to the other behaviour at a communal time rather than at their ideal times. Here we model this situation analytically for groups in which the ideal times vary quasinormally and grouping benefit increases linearly with group size. Across the parameter space consisting of variation in the grouping benefit/cost ratio and variation in how costly it is to act too early and too late, the most common optimal solutions are full synchronization with the group staying together and zero synchronization with immediate dissolution of the group, if the group is too small for the given benefit/cost ratio. Partial synchronization, with animals at the tails of the distribution switching individually and the central core of the group in synchrony, occurs only at a narrow stripe of the space. Synchronization cost never causes splitting of the group into two as either zero, partial or full synchronization is always more advantageous. Stable solutions dictate lower degree of synchrony and lower net benefits than optimal solutions for a large range of the parameter values. If groups undergo repeated synchronization challenges, they stay together or quickly dissolve, unless the animals assort themselves into a smaller group with less variation in the ideal times. We conclude with arguing that synchronization cost is different from other types of grouping costs since it does not increase much with increasing group size. As a result, larger groups may be more stable than smaller groups. This results in the paradoxical prediction that when the grouping benefit/grouping cost ratio increases, the average group sizes might decrease, since smaller groups will be able to withstand synchronization challenges.
