Socially-mediated arousal and contagion within domestic chick broods

Emotional contagion – an underpinning valenced feature of empathy – is made up of simpler, potentially dissociable social processes which can include socially-mediated arousal and behavioural/physiological contagion. Previous studies of emotional contagion have often conflated these processes rather than examining their independent contribution to empathic response. We measured socially-mediated arousal and contagion in 9-week old domestic chicks (n = 19 broods), who were unrelated but raised together from hatching. Pairs of observer chicks were exposed to two conditions in a counterbalanced order: air puff to conspecifics (AP) (during which an air puff was applied to three conspecifics at 30 s intervals) and control with noise of air puff (C) (during which the air puff was directed away from the apparatus at 30 s intervals). Behaviour and surface eye temperature of subjects and observers were measured throughout a 10-min pre-treatment and 10-min treatment period. Subjects and observers responded to AP with increased freezing, and reduced preening and ground pecking. Subjects and observers also showed reduced surface eye temperature - indicative of stress-induced hyperthermia. Subject-Observer behaviour was highly correlated within broods during both C and AP conditions, but with higher overall synchrony during AP. We demonstrate the co-occurrence of socially-mediated behavioural and physiological arousal and contagion; component features of emotional contagion

Expression of emotional arousal in two different piglet call types

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

Analysing the eosinophil cationic protein - a clue to the function of the eosinophil granulocyte

Eosinophil granulocytes reside in respiratory mucosa including lungs, in the gastro-intestinal tract, and in lymphocyte associated organs, the thymus, lymph nodes and the spleen. In parasitic infections, atopic diseases such as atopic dermatitis and asthma, the numbers of the circulating eosinophils are frequently elevated. In conditions such as Hypereosinophilic Syndrome (HES) circulating eosinophil levels are even further raised. Although, eosinophils were identified more than hundred years ago, their roles in homeostasis and in disease still remain unclear. The most prominent feature of the eosinophils are their large secondary granules, each containing four basic proteins, the best known being the eosinophil cationic protein (ECP). This protein has been developed as a marker for eosinophilic disease and quantified in biological fluids including serum, bronchoalveolar lavage and nasal secretions. Elevated ECP levels are found in T helper lymphocyte type 2 (atopic) diseases such as allergic asthma and allergic rhinitis but also occasionally in other diseases such as bacterial sinusitis. ECP is a ribonuclease which has been attributed with cytotoxic, neurotoxic, fibrosis promoting and immune-regulatory functions. ECP regulates mucosal and immune cells and may directly act against helminth, bacterial and viral infections. The levels of ECP measured in disease in combination with the catalogue of known functions of the protein and its polymorphisms presented here will build a foundation for further speculations of the role of ECP, and ultimately the role of the eosinophil

The importance of the altricial – precocial spectrum for social complexity in mammals and birds:A review

Various types of long-term stable relationships that individuals uphold, including cooperation and competition between group members, define social complexity in vertebrates. Numerous life history, physiological and cognitive traits have been shown to affect, or to be affected by, such social relationships. As such, differences in developmental modes, i.e. the ‘altricial-precocial’ spectrum, may play an important role in understanding the interspecific variation in occurrence of social interactions, but to what extent this is the case is unclear because the role of the developmental mode has not been studied directly in across-species studies of sociality. In other words, although there are studies on the effects of developmental mode on brain size, on the effects of brain size on cognition, and on the effects of cognition on social complexity, there are no studies directly investigating the link between developmental mode and social complexity. This is surprising because developmental differences play a significant role in the evolution of, for example, brain size, which is in turn considered an essential building block with respect to social complexity. Here, we compiled an overview of studies on various aspects of the complexity of social systems in altricial and precocial mammals and birds. Although systematic studies are scarce and do not allow for a quantitative comparison, we show that several forms of social relationships and cognitive abilities occur in species along the entire developmental spectrum. Based on the existing evidence it seems that differences in developmental modes play a minor role in whether or not individuals or species are able to meet the cognitive capabilities and requirements for maintaining complex social relationships. Given the scarcity of comparative studies and potential subtle differences, however, we suggest that future studies should consider developmental differences to determine whether our finding is general or whether some of the vast variation in social complexity across species can be explained by developmental mode. This would allow a more detailed assessment of the relative importance of developmental mode in the evolution of vertebrate social systems

Euthanasie van dieren op het primaire bedrijf

The research described in this report was performed at the request of the Dutch ministry for Economic Affairs. It comprises a review of literature and a pilot experiment on farm with a euthanasia method for young piglets. The literature review is a sequel to an earlier report of Wageningen UR Livestock Research, updated with recent literature as well as literature regarding the relevant species. A schematic overview is presented with scientific knowledge regarding the relevant aspects of the euthanasia methods. Described methods are compared with Verordening (EG) Nr. 1099/2009. In the pilot experiment a commercially available method for euthanasia of young piglets was tested on farm. The literature review focussed on pigs, turkeys, sheep (lambs) and goat (kids). There appeared to be no literature regarding goat, possibly/likely methods that have been researched in sheep can be transferred to goat. A large number of methods were found that have been tested on several or all aspects relevant in euthanasia of animals (i.e. welfare, speed and effectiveness). Methods can be grouped in three categories: mechanical, electrical and gaseous. A fourth category is a lethal injection, but since this method is allowed for veterinarians only, it was not included. Methods aren’t always compliant with Verordening (EG) Nr. 1099/2009, however. Methods that are compliant with this regulation, on the other hand, haven’t always been researched on all relevant aspects. Mechanical methods that scored positive in literature on welfare, speed and effectiveness, are: non-penetrating captive bolt (in turkeys, piglets until 9 kg BW and lambs) and the penetrating captive bolt (in pigs and lambs). Of different gaseous euthanasia methods CO2 has been researched the most, where effect on welfare, speed and effectivity are highly dependent on the execution. Several methods are commercially available, but haven’t been researched on all critical aspects, examples being nitrogen foam (in all mentioned species), the Zephyr-E (in pigs over 9 kg BW, lambs and kids) en possibly the VetCon Aurelia P (in turkeys). Literature also mentions several aspects that require attention, for example the extent of the brain injury caused by mechanical methods. Development of user protocols that ensure safe as well as effective application of methods are mandatory. One specific aspects in those protocols should be the method of fixation of animals during euthanasia. Besides welfare, speed and effectiveness of different methods, the esthetical as well as societal side is an aspects of consideration. In an on farm pilot experiment the Zephyr-E, a non-penetrating captive bolt that has been researched in the UK and Canada, has been tested. In the experiment 25 piglets weighing 0.5 to 9 kg have been euthanized using the Zephyr-E, without using an additional killing method. The effectiveness of the method was assessed by testing several reflexes, as well as brain and heart activity. The use of the Zephyr-E resulted in immediate loss of reflexes (indicative for loss of consciousness). No animal regained consciousness. Practically, applying the Zephyr in very small animals requested careful placement. Fixation of the animal during euthanasia was a point of consideration. After the use of the device, muscle contractions were noticed in all animals and were a concern to the user. It appeared that in very small piglets (<1 kg) a fracture of the skull could occur, which is not allowed in Verordening (EG) Nr. 1099/2009. Possibly, an adjusted in the air pressure could prevent this