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Individual behavioural characteristics in pigs and their consequences for pig husbandry
No full textIntroductionThe main aspect of this thesis is individual behavioural variation. Behavioural variability among individuals within a population may provide information on strategies or roles in social behaviour, on personality traits and individual recognition. Generally, this behavioural variability becomes overt in stressful situations. Recent data have shown the existence of basically two different coping strategies, active or passive. These different coping styles resemble the two (classical) behavioural stress responses, fight-flight vs. conservation-withdrawal, each with its own characteristic biological pattern. The success of the individual coping response depends on the environmental conditions and, therefore, it is highly surprising that each individual appears to be prediposed to one or the other coping strategy. This suggests a genetic or ontogenetic basis, but recent life experiences will have a significant role also. The idiosyncratic response pattern to a challenge has been shown in many species (humans; monkeys; dogs; tree shrews; etcetera), and hence it may be postulated that this also holds for pigs. If so, these individual behavioural characteristics will have important practical implications in understanding the social relations among group-housed pigs in intensive farm conditions. A stable social structure in the group, and thus a proper group composition, may be a function of the individual behavioural characteristics of each group member. However, until now little research has been conducted to reveal possible patterns underlying a proper group composition in pigs, and subsequently how such mechanisms could be applied in intensive pig husbandry. The present study aims at these aspects.Social statusIn chapter 1, the individual variation in disease susceptibility and immune reactivity of pigs is described in relation to their individual social status in a stable social group. This social status was determined by the outcome of social ranking fights and food competition tests. There was a substantial agreement between the social status determined by these ranking fights and food competition tests. Since these tests were made at quite different ages (respectively; during the suckling period, and on day 50, on day 65, and on day 100), this indicates a relatively stable social structure in the group. At an age of approximately ten weeks, all pigs were challenged intranasally with an Aujeszky virus. Mortality and morbidity were highest among subordinate pigs compared to subdominant and dominant ones. A specific lymphocyte stimulation test, using purified Apjeszky virus as an antigenic stimulus, showed that the cell-mediated immunity (CMI) against the Aujeszky virus was higher for the dominant pigs than for the subdominant and subordinate ones.These findings showed that there were large individual differences in immune reactivity and disease susceptibility in pigs partly related to their individual social status in the group. However, social behaviour of an animal that lives in a social organization is also determined by its individual way of handling stressful situations i.e., its coping strategy. Therefore, the individual coping response may well be another basis for different internal biological programs, which may eventually lead to individual differences in disease susceptibility. In chapter 2 the hypothesis was tested whether consistent individual behavioural characteristics in pigs exist.Individual behavioural characteristicsDuring the suckling period, piglets were classified as aggressive or as non-aggressive individuals in two successive social confrontation (SC) tests by two observers. Substantial agreement in this classification existed between observers and between both SC tests. Moreover, the aggressive behavioural elements observed after mixing at 10 and again at 15 weeks of age were mainly shown by pigs that were classified as the aggressive ones in the two social confrontation tests shortly after birth; this indicates that the behavioural response pattern of the individuals remained consistent over a long period of time. In a non-social backtest piglets were restrained in a supine position for sixty seconds, and classified as resistant (R;>two escape attempts), intermediate Q; = two escape attempts), or as non-resistant (NR; < two escape attempts). Based upon the outcome of five successive backtests piglets were eventually classified as R (n=95), as NR (n=77), or as Doubtful (n=46). Results showed that two backtests performed on piglets at an early age may suffice for practical use. A striking finding was the good association that existed between the outcome of the backtests and of the SC test. The individuals that resisted in the backtests were the aggressive ones in a social situation, while the non-resistant individuals were the non-aggressive ones. This association and the strong consistency over time strongly suggests an individual behavioural strategy to cope with conflict situations. The idiosyncratic characteristics indicate a bimodal distribution in coping behaviour in pigs; they are active (aggressive and resistant; A/R) or passive (non-aggressive and non-resistant; NA/NR) pigs.Individual physiological characteristicsThe way these individual behavioural strategies in pigs relate to different behavioural, physiological, and endocrine responses under stress conditions is illustrated in chapter 3. For this, 32 A/R and 32 NA/NR pigs were selected and individually tested in an open field (OF) test at three and eight weeks of age. While A/R pigs more than NA/NR ones tried to escape the OF, the A/R pigs vocalized less during the OF procedure than the NA/NR ones did. Furthermore, the A/R ones explored a novel object inside the OF rapidly and superficially, whereas the NA/NR ones did so gradually but more intensively. The cortisol response to the OF (t=0/t=90) differed between the A/R and the NA/NR pigs. The cortisol response to a farmacological dosis ACTH 1-39 (2.5 IU/kg live weight/pig) at three and eight weeks of age showed no significant differences between both types of pigs. Nonetheless, the basal cortisol levels were consistently higher for NA/NR pigs than for A/R ones, and this was eventually accompanied by adrenal hypertrophy in the former. The mean heart rate (HR) in beats/min (bpm) was higher of the A/R pigs compared to the NA/NR ones in two backtests. Moreover, in reaction to the novel object (a falling bucket) in the (second) OF HR of the A/R pigs substantially increased (23.9 bpm = 15.5%), while HR of the NA/NR pigs only slightly increased (4.5 bpm = 2.9%). Surprisingly, one-third of the NA/NR individuals even showed a HR decrease (bradycardia) in response to the falling bucket. This implies that the active pigs (A/R) reacted predominantly with a sympathetic response, and the passive pigs (NA/NR) with a parasympathetic one; these findings strongly parallel data found in other animals and humans. The sympathetic response of the active pigs resulted in heart deviations. Thus, active and passive pigs displayed consistent individual differences in behavioural, physiological, and endocrine responses to stress situations leading to different stress pathologies.Individual immunological characteristicsChapter 4 reports about individual differences in cell-mediated and humoral immunity as related to different coping styles in pigs. The immune reactivity of 32 A/R and 32 NA/NR pigs was tested in relation to stress using several cell-mediated (CMI) and humoral immunological tests. Results indicated that the active pigs had a higher in vivo and in vitro CMI to non-specific and specific antigens than the passive pigs. Furthermore, in reaction to stressors applied in the present study (i.e., weaning, new environment, transportation, mixing) active pigs had a reduced but temporary CMI response in the first phase of stress, while passive pigs showed a more chronic impairment. In contrast, the passive pigs displayed higher levels of specific antibodies than the active ones. This suggests a converse relationship in the individual pig between CMI and humoral immunity, in that active pigs had a high CMI but a low humoral immunity, whereas passive pigs had a low CMI but a high humoral immunity. This converse relationship may be associated with different levels of glucocorticoids as described in chapter 3. In conclusion, active and passive pigs clearly differed in their immune reactivity to stressful situations.Practical implicationsHow far group composition based on the individual coping characteristics may influence the growing up of fattening pigs was tested at a commercial closed farm (cf. chapter 5). During the suckling period, piglets of this farm were individually tested in two successive backtests, and classified as R, NR, or as D. At nine weeks of age, the pigs were grouped into six pens with only R pigs (R pens), six pens with only NR pigs (NR pens), and six pens with both R and NR ones (R/NR pens). The average daily weight gain (ADWG; grams/day) was highest of the pigs in the R/NR pens compared to the pigs in the R pens and in the NR pens. Moreover, the coefficient of variation of A~ was lower among R/NR pens than among R pens or NR pens. The carcass weight and meat% was somewhat higher and carcass classification was better of the pigs in the R/NR pens than the pigs in the R pens and in the NR pens. Additionally, pigs in the R/NR pens had less pleurisy than the pigs in the other pens, whereas the number of pigs with stomach wall damage was highest for pigs in the NR pens. Groups consisting of both active (R pigs) and passive (NR pigs) individuals seem to better fit each other than groups with only active or with only passive ones and, thus it is worthwhile to compose groups of pigs based on their individual behavioural characteristics. In practice, good management implies besides perfect climatic and feeding conditions also attention for and understanding of the social environment of the farm animals.General DiscussionIn the general discussion three major topics are discussed: 1) do the behavioural differences in pigs represent idiosyncratic response patterns; 2) do the individual behavioural characteristics in pigs relate to different autonomic nervous and immune reactivity under stress conditions and 3) the relevance of applying behavioural studies in pigs in practice. Especially the intriguing finding that under stressful conditions active and passive pigs need each other to develop a stable social organization needs further research
Individual behavioural characteristics in pigs and their consequences for pig husbandry
No full textIntroductionThe main aspect of this thesis is individual behavioural variation. Behavioural variability among individuals within a population may provide information on strategies or roles in social behaviour, on personality traits and individual recognition. Generally, this behavioural variability becomes overt in stressful situations. Recent data have shown the existence of basically two different coping strategies, active or passive. These different coping styles resemble the two (classical) behavioural stress responses, fight-flight vs. conservation-withdrawal, each with its own characteristic biological pattern. The success of the individual coping response depends on the environmental conditions and, therefore, it is highly surprising that each individual appears to be prediposed to one or the other coping strategy. This suggests a genetic or ontogenetic basis, but recent life experiences will have a significant role also. The idiosyncratic response pattern to a challenge has been shown in many species (humans; monkeys; dogs; tree shrews; etcetera), and hence it may be postulated that this also holds for pigs. If so, these individual behavioural characteristics will have important practical implications in understanding the social relations among group-housed pigs in intensive farm conditions. A stable social structure in the group, and thus a proper group composition, may be a function of the individual behavioural characteristics of each group member. However, until now little research has been conducted to reveal possible patterns underlying a proper group composition in pigs, and subsequently how such mechanisms could be applied in intensive pig husbandry. The present study aims at these aspects.Social statusIn chapter 1, the individual variation in disease susceptibility and immune reactivity of pigs is described in relation to their individual social status in a stable social group. This social status was determined by the outcome of social ranking fights and food competition tests. There was a substantial agreement between the social status determined by these ranking fights and food competition tests. Since these tests were made at quite different ages (respectively; during the suckling period, and on day 50, on day 65, and on day 100), this indicates a relatively stable social structure in the group. At an age of approximately ten weeks, all pigs were challenged intranasally with an Aujeszky virus. Mortality and morbidity were highest among subordinate pigs compared to subdominant and dominant ones. A specific lymphocyte stimulation test, using purified Apjeszky virus as an antigenic stimulus, showed that the cell-mediated immunity (CMI) against the Aujeszky virus was higher for the dominant pigs than for the subdominant and subordinate ones.These findings showed that there were large individual differences in immune reactivity and disease susceptibility in pigs partly related to their individual social status in the group. However, social behaviour of an animal that lives in a social organization is also determined by its individual way of handling stressful situations i.e., its coping strategy. Therefore, the individual coping response may well be another basis for different internal biological programs, which may eventually lead to individual differences in disease susceptibility. In chapter 2 the hypothesis was tested whether consistent individual behavioural characteristics in pigs exist.Individual behavioural characteristicsDuring the suckling period, piglets were classified as aggressive or as non-aggressive individuals in two successive social confrontation (SC) tests by two observers. Substantial agreement in this classification existed between observers and between both SC tests. Moreover, the aggressive behavioural elements observed after mixing at 10 and again at 15 weeks of age were mainly shown by pigs that were classified as the aggressive ones in the two social confrontation tests shortly after birth; this indicates that the behavioural response pattern of the individuals remained consistent over a long period of time. In a non-social backtest piglets were restrained in a supine position for sixty seconds, and classified as resistant (R;>two escape attempts), intermediate Q; = two escape attempts), or as non-resistant (NR; < two escape attempts). Based upon the outcome of five successive backtests piglets were eventually classified as R (n=95), as NR (n=77), or as Doubtful (n=46). Results showed that two backtests performed on piglets at an early age may suffice for practical use. A striking finding was the good association that existed between the outcome of the backtests and of the SC test. The individuals that resisted in the backtests were the aggressive ones in a social situation, while the non-resistant individuals were the non-aggressive ones. This association and the strong consistency over time strongly suggests an individual behavioural strategy to cope with conflict situations. The idiosyncratic characteristics indicate a bimodal distribution in coping behaviour in pigs; they are active (aggressive and resistant; A/R) or passive (non-aggressive and non-resistant; NA/NR) pigs.Individual physiological characteristicsThe way these individual behavioural strategies in pigs relate to different behavioural, physiological, and endocrine responses under stress conditions is illustrated in chapter 3. For this, 32 A/R and 32 NA/NR pigs were selected and individually tested in an open field (OF) test at three and eight weeks of age. While A/R pigs more than NA/NR ones tried to escape the OF, the A/R pigs vocalized less during the OF procedure than the NA/NR ones did. Furthermore, the A/R ones explored a novel object inside the OF rapidly and superficially, whereas the NA/NR ones did so gradually but more intensively. The cortisol response to the OF (t=0/t=90) differed between the A/R and the NA/NR pigs. The cortisol response to a farmacological dosis ACTH 1-39 (2.5 IU/kg live weight/pig) at three and eight weeks of age showed no significant differences between both types of pigs. Nonetheless, the basal cortisol levels were consistently higher for NA/NR pigs than for A/R ones, and this was eventually accompanied by adrenal hypertrophy in the former. The mean heart rate (HR) in beats/min (bpm) was higher of the A/R pigs compared to the NA/NR ones in two backtests. Moreover, in reaction to the novel object (a falling bucket) in the (second) OF HR of the A/R pigs substantially increased (23.9 bpm = 15.5%), while HR of the NA/NR pigs only slightly increased (4.5 bpm = 2.9%). Surprisingly, one-third of the NA/NR individuals even showed a HR decrease (bradycardia) in response to the falling bucket. This implies that the active pigs (A/R) reacted predominantly with a sympathetic response, and the passive pigs (NA/NR) with a parasympathetic one; these findings strongly parallel data found in other animals and humans. The sympathetic response of the active pigs resulted in heart deviations. Thus, active and passive pigs displayed consistent individual differences in behavioural, physiological, and endocrine responses to stress situations leading to different stress pathologies.Individual immunological characteristicsChapter 4 reports about individual differences in cell-mediated and humoral immunity as related to different coping styles in pigs. The immune reactivity of 32 A/R and 32 NA/NR pigs was tested in relation to stress using several cell-mediated (CMI) and humoral immunological tests. Results indicated that the active pigs had a higher in vivo and in vitro CMI to non-specific and specific antigens than the passive pigs. Furthermore, in reaction to stressors applied in the present study (i.e., weaning, new environment, transportation, mixing) active pigs had a reduced but temporary CMI response in the first phase of stress, while passive pigs showed a more chronic impairment. In contrast, the passive pigs displayed higher levels of specific antibodies than the active ones. This suggests a converse relationship in the individual pig between CMI and humoral immunity, in that active pigs had a high CMI but a low humoral immunity, whereas passive pigs had a low CMI but a high humoral immunity. This converse relationship may be associated with different levels of glucocorticoids as described in chapter 3. In conclusion, active and passive pigs clearly differed in their immune reactivity to stressful situations.Practical implicationsHow far group composition based on the individual coping characteristics may influence the growing up of fattening pigs was tested at a commercial closed farm (cf. chapter 5). During the suckling period, piglets of this farm were individually tested in two successive backtests, and classified as R, NR, or as D. At nine weeks of age, the pigs were grouped into six pens with only R pigs (R pens), six pens with only NR pigs (NR pens), and six pens with both R and NR ones (R/NR pens). The average daily weight gain (ADWG; grams/day) was highest of the pigs in the R/NR pens compared to the pigs in the R pens and in the NR pens. Moreover, the coefficient of variation of A~ was lower among R/NR pens than among R pens or NR pens. The carcass weight and meat% was somewhat higher and carcass classification was better of the pigs in the R/NR pens than the pigs in the R pens and in the NR pens. Additionally, pigs in the R/NR pens had less pleurisy than the pigs in the other pens, whereas the number of pigs with stomach wall damage was highest for pigs in the NR pens. Groups consisting of both active (R pigs) and passive (NR pigs) individuals seem to better fit each other than groups with only active or with only passive ones and, thus it is worthwhile to compose groups of pigs based on their individual behavioural characteristics. In practice, good management implies besides perfect climatic and feeding conditions also attention for and understanding of the social environment of the farm animals.General DiscussionIn the general discussion three major topics are discussed: 1) do the behavioural differences in pigs represent idiosyncratic response patterns; 2) do the individual behavioural characteristics in pigs relate to different autonomic nervous and immune reactivity under stress conditions and 3) the relevance of applying behavioural studies in pigs in practice. Especially the intriguing finding that under stressful conditions active and passive pigs need each other to develop a stable social organization needs further research
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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