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The detection of quantitative trait loci (QTL) of behavioural traits has mainly been focussed on mouse and rat. With the rapid development of molecular genetics and the statistical tools, QTL mapping for behavioural traits in farm animals is developing. In chicken, a total of 30 QTL involved in pecking-related traits, open-field behaviour, tonic immobility, response to novel objects, and response to a restraint test were detected in different studies. In the search for a useful early predictor for feather pecking (FP) behaviour in adult laying hens, the following was found: FP in young animals is not a predictor for FP in adult animals, however, open-field behaviour in young animals is genetically correlated with FP in adult hens. Before the implementation of FP behaviour or open-field behaviour in breeding programmes, it is essential to know more about the correlation between these behavioural traits and also their relationship with production traits. Nevertheless, with the QTL for behavioural traits and the chicken genome sequence in progress, a better understanding of the underlying genetic mechanisms of behavioural traits will be feasible.

Characterization of piglets based on the degree of resistance they display in a so-called Backtest is, to a certain extent, predictive of their coping responses to several challenges in later life. It is unknown, however, whether these individual coping characteristics of pigs are also reflected in their behavioural development in different environments. The present study investigated the behavioural development of pigs with diverging Backtest responses, high-resisting (HR) and low-resisting (LR) pigs, in both barren housing and housing enriched with straw bedding. During the suckling period, pigs were subjected to the Backtest. Pigs classified as HR ( n = 30) or LR ( n = 30) were selected and after weaning housed in groups of six (three LR and three HR) in either barren or enriched pens. Home pen behaviour was recorded at 5, 9, 15 and 19 weeks of age for 8 h per week using 2-min instantaneous scan sampling. Housing environment markedly influenced behaviour of pigs. Barren housed pigs were less active, showed less explorative and play behaviour, and spent more time on oral activities directed at pen mates than pigs from enriched housing. HR pigs showed more aggressive behaviour than LR pigs and they tended to be less active in both environments. LR pigs spent more time on manipulating pen mates, in particular in barren housing. In addition, they played more than HR pigs in enriched pens. In conclusion, an enriched housing environment, i.e. availability of straw bedding, appeared to improve welfare as it increased play behaviour and decreased manipulative oral behaviour directed at pen mates in comparison with barren housing conditions. Individual coping characteristics of pigs, as assessed in the Backtest, were also reflected in their home pen behaviour. Notably, the effects of housing on both manipulative and play behaviour were most obvious in LR pigs.

Om na te gaan of voedsters behoefte hebben aan ruwvoer is een kooi met keuzemogelijkheden ontwikkeld volgens het consumer-demand model. Begin dit jaar is men gestart met een eerste ronde, waarin voedsters konden kiezen tussen drie soorten ruwvoer. In dit artikel wordt ingegaan op dit onderzoek

Individual pigs, Sus scrofa, differ considerably in how aggressive they are during encounters with unfamiliar conspecifics. We examined whether individual coping characteristics of pigs were predictive of aggression during social encounters and the resulting social status. Piglets were subjected to the Backtest during the suckling period, as their behavioural response in this test seems to be predictive of their coping style. Each piglet was restrained in a supine position for 1 min and the resistance (i.e. number of escape attempts) was scored. After weaning, 30 `high-resisting¿ (HR) and 30 `low-resisting¿ (LR) pigs were regrouped with unfamiliar pigs of similar weight and we recorded their aggressive behaviour for 180 min. In addition, we assessed the social rank of each pig. HR pigs showed more aggressive behaviour than LR pigs: they initiated more fights, started fighting earlier and spent more time fighting during the observation period. HR and LR pigs did not differ, however, in achieved social rank. Level of self-initiated fighting was positively correlated with social rank in LR pigs, but this relation was not found in HR pigs. In conclusion, the coping style of pigs is related to their aggressive behaviour and the establishment of dominance relationships after mixing. Our results indicate that LR pigs are flexible in using aggression, whereas the high level of aggression of HR pigs regardless of their success in encounters suggests that these animals are more rigid in their aggressive behaviour.

Although the consequences of stress and hypercortisolemia for the rodent hippocampal dentate gyrus (DG) are well known, little is known about other species. For pigs, tethered housing represents a well-established chronic stressor that shares many similarities with restraint paradigms, as evidenced by profound changes in behavior and autonomic and endocrine dysfunction, including flattened cortisol rhythms and hypercortisolemia--all conditions that may threaten hippocampal viability in rat. Here, we studied structural parameters of the porcine DG after 5 months of tethered housing in relation to basal saliva cortisol measured antemortem. We further investigated whether any neuropathology or alterations in apoptosis had occurred in the left hippocampal hemisphere. Stereological analysis revealed high correlations between DG volume and neuron number in individual animals in both hemispheres. Within individual animals, neuron numbers of the left and right lobes were not correlated. Notably, basal cortisol was negatively correlated with volume and neuron number of the left, but not the right DG. Although obvious neuropathology was absent, apoptosis was present in DG and alveus and less so in CA areas. Despite the short window of time during which apoptosis is detectable, their stereologically estimated numbers in the DG, but not in other regions, were negatively correlated with cortisol. In conclusion, our data indicate for the first time a profound lateralization in the relationship between DG structure, apoptosis, and basal cortisol after stress in pigs. Five months of chronic stress failed to induce lasting neuropathology. Although accumulating changes in apoptosis could have contributed to the structural DG alterations, further studies should reveal whether stress has been instrumental, or whether the differences between animals were present from birth onward. The present lateralization after stress is, however, consistent with lateralized hippocampal volume changes in stress-related human disorders and suggests that these effects are not limited to this species alone.

The objective of the current study was to estimate genetic and phenotypic correlations among feather pecking (FP) behavior and stress response, immune response, and egg quality parameters. These traits have been measured in an F-2 cross, coming from a cross between a high and a low FP line of laying hens. Heritabilities (h 2) of stress response (32 wk), primary immune response to keyhole limpet hemocyanin (KLH) (36 wk) and Mycobacterium butyricum (39 wk), and egg quality parameters (35, 44, and 50 wk of age) were calculated. The h 2 was 0.05 +/- 0.05 (SE) for stress response, 0.15 +/- 0.07 for antibody response to KLH, and 0.08 +/- 0.06 for antibody response to M. butyricum. The h 2 for egg quality traits were in the range of 0.12 to 0.30. Significant phenotypic correlations were found between gentle FP in adult hens and stress response, egg weight at 44 and 50 wk, and egg deformation at 50 wk. Significant additive genetic correlations were found between severe FP in adult hens and antibody response to KLH (0.79 +/- 0.35), and between ground pecking in adult hens and egg deformation at 50 wk (0.63 +/- 0.26), and between ground pecking and eggshell strength at 35, 44, and 50 wk of age (-0.86 +/- 0.29, -0.81 +/- 0.20, -0.76 +/- 0.24, respectively).

Line differences for open-field behavior in chickens have been observed, and it has been shown that this behavior has a genetic component. The aim of this study was to detect quantitative trait loci (QTL) involved in open-field behavior. For this purpose, open-field behavior was studied at 5 and 29 weeks of age in F(2) hens coming from an intercross between two commercial White Leghorn laying lines selected for egg production traits. Latencies, durations, and frequencies of general activity (sitting, standing, walking, and stepping), defecation, and vocalizations were recorded individually for each bird, and a factor score was calculated. All animals (F(0), F(1), and F(2)) were screened with 180 microsatellite markers. Regression interval mapping was applied using both a paternal half-sib analysis and a line-cross analysis method. For general activity at 5 weeks of age, a significant QTL was detected on GGA4 and a suggestive QTL on GGA2 under the line-cross model. For general activity at 29 weeks of age, a significant QTL was detected on GGA4 and two suggestive QTLs were detected on GGA1 and on GGA10, respectively, also using the line-cross analysis. The QTL on GGA4 at 5 weeks of age did not overlap with the QTL on GGA4 at 29 weeks of age. The current study indicated that open-field behavior in young chickens was regulated by QTL that differ from the QTL for open-field behavior in adult chickens.

Several studies suggest that classification of piglets early in life based on the degree of resistance they display in a so-called Backtest may be indicative of their coping style at a later age. In the present study behavioural flexibility was investigated in pigs diverging for Backtest response and housing environment during rearing. Pigs were housed either without a rooting substrate (barren housing, 13) or in identical pens enriched with deep straw bedding (enriched housing, E) from birth. During the suckling period piglets were subjected to the Backtest. Each piglet was restrained on its back for I min and the resistance (i.e. number of escape attempts) was scored. Pigs classified as 'high-resisting' (HR) or as 'low-resisting' (LR) were subjected to a simple (left/right) spatial discrimination (T-maze) task at 8 weeks of age. The effect of a single, subtle intramaze change was determined after acquisition of the task. In addition, pigs were subjected to reversal learning to assess their ability to modulate established behaviour patterns. Housing and its interaction with Backtest classification influenced the behavioural response to the intramaze change: E pigs were considerably more distracted than B pigs. Housing condition affected LR pigs more than HR pigs, as indicated by the interaction effects on various recorded behaviours. These interactions indicate that behavioural responding of pigs with diverging coping characteristics cannot simply be generalised across rearing conditions. Furthermore, FIR pigs were less successful in reversal learning than LR pigs, suggesting that they have a higher propensity to develop inflexible behavioural routines. (C) 2003 Elsevier B.V. All rights reserved.

Stadskippen of kippen die verwilderen in de omgeving van mensen kunnen een probleem vormen. Zo bezorgde een populatie verwilderde kippen in de omgeving van het Amsterdamse Amstelpark zoveel overlast dat de gemeente besloot dieren weg te vangen. Een groep verontruste burgers richtte daarop de Werkgroep Park en Fauna op om zich te verzetten tegen deze, in hun ogen weinig duurzame manier van beheer. Immers, de populatie zou zeker weer toenemen. De werkgroep vroeg de Wetenschapswinkel meer duurzame en diervriendelijke beheersmethoden aan te reiken. De onderzoekers doen literatuuronderzoek naar de geschiedenis van de kip in de westerse samenleving en naar de leefwijze van wilde kippen. Aan de hand van twee voorbeelden (het Amstelpark en het industrieterrein van Alkmaar) schetsen zij vervolgens een aantal beheers-technieken. Zij onderscheiden in hun rapport de volgende mogelijkheden om overlast tegen te gaan: (i) het voorkómen van vrijlopende populaties (tegengaan dat mensen kippen vrijlaten door bijvoorbeeld voorlichting of verbodsbepalingen); (ii) het belemmeren van de voortplanting door eimanipulatie (bijvoorbeeld het schudden of lekprikken van eieren zodat deze niet meer uitkomen). Wel moet daarbij nestmogelijkheid wordt aangeboden om controle en manipulatie mogelijk te maken; (iii) slechts in noodgevallen gebruik maken van 'curatieve' maatregelen, zoals wegvangen van kippen en het tegengaan van het voederen van kippen op ongewenste plekken door de bevolking.Wet- en regelgeving bieden nauwelijks aanknopingspunten om het probleem met wilde kippenpopulaties op te lossen. Wel kunnen gemeentes die dit probleem serieus willen aanpakken, onderzoeken welke van de genoemde maatregelen voor de eigen gemeente het beste zijn en vervolgens een beheersplan opstellen, voorzien van budget

There are indications that pigs may have difficulty in adapting to the constraints of intensive housing conditions. Pigs show a wide variation in adaptive responses when exposed to the same stressful situation. Aim of this thesis was to investigate whether the behavioural coping responses of young piglets reflect and predict more general profiles of reactivity to challenges, often referred to as coping styles, under different rearing and housing conditions. For this purpose, pigs were characterized early in life as `high-resisting` (HR) or `low-resisting` (LR) on the basis of their resistance response in a so-called Backtest, in which they were manually restrained in supine position. The major part of the thesis focused on the interaction between these individual coping characteristics of pigs and their housing environment, which was either barren or enriched with straw bedding. The experiments described in this thesis show that HR pigs are more aggressive than LR pigs and less flexible in adapting their behaviour to environmental changes. As the two types of pig differed in response to the dopamine-agonist apomorphine, some initial evidence is provided for a neurochemical background of these behavioural differences. In addition, individual coping or personality characteristics of pigs were reflected in immune reactivity and in their home pen behaviour in barren and enriched environments. HR and LR pigs adapted differently to barren housing conditions. Moreover, individual characteristics modulated the effects of rearing and housing conditions on the behavioural response to novelty, immune reactivity, prevalence of gastric lesions and behavioural development. Remarkably, for almost all of the variables that were affected by housing environment, the impact was much larger for LR than for HR pigs. Thus, individual characteristics of pigs affect their performance in different environments and should be taken into account when studying the impact of housing on their behaviour and welfare. The knowledge of individual coping or personality characteristics could be extended and used for finding the optimal match between pigs and their social and physical environment in pig husbandry.

Broilers are chickens kept commercially under intensive husbandry conditions for poultry meat production. They grow to a slaughterweight of approximately 2.2 kg in 6 weeks. Broilers show a pronounced decrease in behavioural activity during their short life. The aim of this thesis was to gain more insight into the influence of both motivation and ability on behavioural activity in broilers. The distinction between motivation and ability is relevant for the interpretation of behavioural activity in broilers in terms of welfare. Broilers were observed when kept in pens with good facilities and in several ex situ tests where they had to work for food. Broilers showed all normal juvenile chicken behaviours, but the time spenton each behaviourhas changed. Many behavioural patterns were shown in a sitting posture instead of in a standing posture. Performance in short physical tasks depended on motivation and physical ability. Hunger and satiety mechanisms have changed compared to layer chickens, but the motivation to work for food still can be manipulated in broilers. Broilers are willing to peck a key many times or to walk long distances to obtain food rewards, but their performance seemed to be dependent on body weight. Apart from having an abnormal high motivation to eat, broilers are normal biologically functioning animals. Parallel to the effect of overweight on the quality of life in humans, the abnormal high body weight at a young age has a negative impact on the welfare of broilers. Broilers are restricted to display behaviours for which they are motivated imposed by their high motivation to eat, which is associated with their fast growth and high body weight at young age, or by environmental conditions in which they are usually kept.

The aim of this paper is to present new insights and promising directions for future research on feather pecking in laying hens. Our starting point was a multidisciplinary research program on feather pecking in The Netherlands, in which ethological, physiological, ontogenetic and genetic approaches were combined. The four topics addressed in this paper are: (1) the relation between gentle and severe feather pecking, (2) feather pecking and coping strategy, (3) causation of feather pecking, and (4) the possibility to solve the problem of feather pecking through genetic selection. When the relationship between gentle and severe feather pecking was studied, it was found that both forms of feather pecking are related at the same age. Gentle feather pecking at young age, however, could not be used as a predictor of feather pecking at adult age. Birds from high and low feather pecking lines that showed differences in feather pecking also differed in other behavioural and physiological characteristics. This may reflect line differences in coping strategy. Relating coping strategy with feather pecking may help us to better understand the motivations and characteristics underlying the development of feather pecking. On the causation of feather pecking, there is some evidence that it is redirected ground pecking, deriving either from a foraging or a dustbathing background. However, evidence was found that early feather pecking could also be interpreted as social exploration. Finally, the use of molecular genetics to help solving the problem of feather pecking seems promising. Feather pecking has been shown to be heritable and the first genetic regions (QTL) involved in feather pecking have been identified. To search for a solution for the feather pecking problem it is of importance to identify the mechanisms involved in the development of feather pecking. In this paper, we have combined approaches from different disciplines in order to study feather pecking. The results indicate that combined efforts of multidisciplinary research can be very useful in looking for possible ways to reduce feather pecking in practice. (C) 2004 Elsevier B.V. All rights reserved.

Characterizing feather peckers seems a viable approach towards a better understanding of the problem of feather pecking. With our current state of knowledge on the causation of feather peckinq, the environmental factors that influence the development of feather pecking and the characteristics of feather peckers and non-feather peckers, it should be possible to achieve more control over the problem of feather pecking in European flocks

The behavioral response of piglets in a backtest early in life seems indicative of their coping strategy at a later age. Coping characteristics may depend on the interaction between backtest classification and housing conditions. We studied whether growth rate and partitioning of energy in adult gilts were related to response in the backtest early in life, and to housing in groups or individual stalls. During the suckling period, female piglets were subjected to the backtest. Each piglet was restrained on its back for 1 min, and the number of escape attempts was scored. Thirty-six high-resisting gilts and 36 low-resisting gilts were selected. After weaning, pigs were housed in 12 groups of six (three high-resisting and three low-resisting). From 7 mo of age onward, 36 gilts out of six groups were housed in individual stalls, whereas the other gilts remained group housed. At 13 mo of age, gilts were housed in clusters of three (three high-resisting or three low-resisting) for an experimental period of 7 d in climatic respiration chambers. Group-housed gilts were loose housed, and stall-housed gilts were housed in stalls within the chamber. Despite the fact that high-resisting and low-resisting gilts did not differ (P = 0. 269) in initial BW, low-resisting gilts showed a higher (P = 0.039) ADG during the experimental period in association with a higher (P = 0.043) energy metabolizability. This suggests that, in line with the theory on coping strategies, high-resisting gilts may have more difficulties in adapting to a change in environment, (i.e., the change from home pen to climatic chamber). Group-and stall-housed gilts differed (P = 0.001) in initial BW, with group-housed gilts being heavier. During the experimental period, stall-housed gilts showed lower energy metabolizability (P = 0.001), lower energy retention (P = 0.001), and a higher energy requirement for maintenance (P = 0. 001) due to a higher activity-related heat production (P = 0.001). This finding suggests that stall housing might have a negative influence on performance and partitioning of energy when animals are adapting to a change in their environment.

There are indications that pigs may have difficulty in adapting to the constraints of intensive housing conditions. Pigs show a wide variation in adaptive responses when exposed to the same stressful situation. Aim of this thesis was to investigate whether the behavioural coping responses of young piglets reflect and predict more general profiles of reactivity to challenges, often referred to as coping styles, under different rearing and housing conditions. For this purpose, pigs were characterized early in life as `high-resisting` (HR) or `low-resisting` (LR) on the basis of their resistance response in a so-called Backtest, in which they were manually restrained in supine position. The major part of the thesis focused on the interaction between these individual coping characteristics of pigs and their housing environment, which was either barren or enriched with straw bedding. The experiments described in this thesis show that HR pigs are more aggressive than LR pigs and less flexible in adapting their behaviour to environmental changes. As the two types of pig differed in response to the dopamine-agonist apomorphine, some initial evidence is provided for a neurochemical background of these behavioural differences. In addition, individual coping or personality characteristics of pigs were reflected in immune reactivity and in their home pen behaviour in barren and enriched environments. HR and LR pigs adapted differently to barren housing conditions. Moreover, individual characteristics modulated the effects of rearing and housing conditions on the behavioural response to novelty, immune reactivity, prevalence of gastric lesions and behavioural development. Remarkably, for almost all of the variables that were affected by housing environment, the impact was much larger for LR than for HR pigs. Thus, individual characteristics of pigs affect their performance in different environments and should be taken into account when studying the impact of housing on their behaviour and welfare. The knowledge of individual coping or personality characteristics could be extended and used for finding the optimal match between pigs and their social and physical environment in pig husbandry.

Stadskippen of kippen die verwilderen in de omgeving van mensen kunnen een probleem vormen. Zo bezorgde een populatie verwilderde kippen in de omgeving van het Amsterdamse Amstelpark zoveel overlast dat de gemeente besloot dieren weg te vangen. Een groep verontruste burgers richtte daarop de Werkgroep Park en Fauna op om zich te verzetten tegen deze, in hun ogen weinig duurzame manier van beheer. Immers, de populatie zou zeker weer toenemen. De werkgroep vroeg de Wetenschapswinkel meer duurzame en diervriendelijke beheersmethoden aan te reiken. De onderzoekers doen literatuuronderzoek naar de geschiedenis van de kip in de westerse samenleving en naar de leefwijze van wilde kippen. Aan de hand van twee voorbeelden (het Amstelpark en het industrieterrein van Alkmaar) schetsen zij vervolgens een aantal beheers-technieken. Zij onderscheiden in hun rapport de volgende mogelijkheden om overlast tegen te gaan: (i) het voorkómen van vrijlopende populaties (tegengaan dat mensen kippen vrijlaten door bijvoorbeeld voorlichting of verbodsbepalingen); (ii) het belemmeren van de voortplanting door eimanipulatie (bijvoorbeeld het schudden of lekprikken van eieren zodat deze niet meer uitkomen). Wel moet daarbij nestmogelijkheid wordt aangeboden om controle en manipulatie mogelijk te maken; (iii) slechts in noodgevallen gebruik maken van 'curatieve' maatregelen, zoals wegvangen van kippen en het tegengaan van het voederen van kippen op ongewenste plekken door de bevolking.Wet- en regelgeving bieden nauwelijks aanknopingspunten om het probleem met wilde kippenpopulaties op te lossen. Wel kunnen gemeentes die dit probleem serieus willen aanpakken, onderzoeken welke van de genoemde maatregelen voor de eigen gemeente het beste zijn en vervolgens een beheersplan opstellen, voorzien van budget

From 26 to 28 May 2004 an international seminar was held in Wageningen, the Netherlands, about current knowledge and advice on rodent management on organic pig and poultry farms in Western Europe. This paper summarizes the discussions. Rodent management is necessary to protect the food production chain from health hazards to livestock and humans. Some organic farmers prefer biological rodent control, but since rodents can also transmit diseases this bears certain risks for the production of healthy livestock and safe food. Effective rodent management requires a thorough understanding of the biology of the pest species concerned. These can be divided into two groups: field rodents, such as voles, and commensal rodents like house mice and rats. The objective of managing field rodents is to minimize livestock exposure to these vectors, and to regulate their populations in case their density is expected to grow dramatically. Infestation of livestock facilities with commensal rodents can be prevented, but once they are present, their eradication must be aimed for. General elements of rodent management are (1) the prevention of rodent infestations through strategic actions such as modifying the habitat or rodent proofing of the buildings, (2) monitoring their appearance and population density, and (3) rodent control measures. A number of possible management actions is described to provide a basis for examining the measures' social acceptability, their economic and environmental impacts, and their efficacy.

Increasing milk yields in modern dairy cows cause concern that high yield may impair the cows' health and welfare, for example, via negative effects on metabolic status and hypothalamo-pituitary-adrenocortical (HPA) function. This study aims to investigate whether a high level of milk production, and the associated metabolic status, affects HPA function in dairy cows and changes their adaptive capacity. Additionally, it aims to establish whether possible effects of milk production level only show under challenging conditions. Holstein-Friesian cows, which produced on average 11,443 and 7727 kg of fat and protein-corrected milk (FPCM)/305 d in their previous lactation, were compared. During the dry period, the cows were fed to requirements or overfed. High milk yield and the concomitant large energy deficit were associated with 1) increased pituitary (re)activity, i.e., increased ACTH baseline concentrations and higher ACTH concentrations after corticotropin-releasing hormone (CRH) administration, and 2) decreased adrenocortical reactivity, i.e., lower cortisol responses after ACTH administration. Although significant, the effects of milk production level on HPA function were relatively small. Animals showed seemingly normal hormonal responses to CRH and ACTH administration. Also, cortisol baseline concentrations were unaffected. It seems, therefore, unlikely that the adaptive capacity of the high-producing cows was significantly impaired compared with their low-producing herdmates.

Feather pecking is a major welfare and economic problem in laying hens. It is characterised by pecking at- and pulling out of feathers of conspecifics. A bird's propensity to develop feather pecking may be related with other behavioural characteristics, such as reaction to frustration (the omission of expected reward) and social motivation. Furthermore, differences in feather pecking between lines indicate that genetic background plays an important role.In this thesis, the relationship between feather pecking and other behavioural characteristics was studied in two lines that differed in feather pecking behaviour: the high (HFP) and low (LFP) feather pecking lines. The importance of the social environment was evaluated in an experiment where different tests to measure feather pecking were compared. Furthermore, the reaction to frustration was studied in these lines and it was studied whether frustration can facilitate feather pecking directly. In a behaviour genetics study, it was studied whether behavioural traits measured at young age were predictive of feather pecking at adult age.It was found that the social environment plays an important role in the development of feather pecking. Pecking at a bunch of feathers in an individual context is not comparable with feather pecking in a social group. Although HFP and LFP lines showed differences in reaction to frustration, short-term frustration in a Skinnerbox could not facilitate feather pecking. Finally open-field behaviour at young age was found to be predictive of pecking behaviour at adult age. These results were used to develop a model on the relationship between feather pecking and other behavioural characteristics, that may be helpful to solve the problem of feather pecking in laying hens.

A number of studies in young pigs have demonstrated a relation between a variety of behavioural and physiological features and the degree of resistance displayed early in life in a so-called “backtest”. The current study aimed at investigating the relation between the backtest response and the development of stereotypies, the circadian rhythm of cortisol, the heart rate response to feeding, and pathological lesions of heart, lungs and stomach of adult breeding gilts. At 10 and 17 days of age, female piglets were subjected to the backtest. In this test, each piglet is restrained on its back for 1 min and the number of escape attempts is scored. Pigs classified as high-resisting (HR, n =36) or low-resisting (LR, n =36) were selected and housed in groups of six (3 HR, 3 LR). At 7 months of age, half of the groups were housed in individual stalls. Time spent chain biting by stall-housed gilts during 2 h after afternoon feeding was studied at regular intervals for 21 weeks. At 11 months of age, saliva was collected from all animals every hour during 24 h for cortisol analysis. At 8 and at 12 months of age, heart rate of all animals was measured around afternoon feeding. Pigs were slaughtered at 14 months of age and heart, lungs and stomach were macroscopically examined. Over time, stall-housed HR gilts tended to show more chain biting, had lower circadian cortisol concentrations and showed a diminished heart rate response to feed delivery compared to LR gilts. In group-housed gilts, the circadian rhythm of cortisol and the heart rate response to feed delivery did not relate to the backtest response. Stall-housed gilts had lower circadian cortisol concentrations than group-housed gilts. The prevalence of pathological lesions was not influenced by backtest type. Stomach wall damage was more severe in stall-housed than in group-housed gilts.

The aim of this experiment was to select a suitable test to measure feather pecking in laying hens. Pecking behaviour in individual and social feather pecking tests was compared with pecking behaviour in the homepen. Two lines of laying hens were used that differ in their propensity to display feather pecking: the high feather pecking (HFP) and low feather pecking (LFP) lines. Six groups of five birds per line were housed on wood shavings with ad libitum food and water. From 7 to 34 weeks of age, every 3 weeks pecking behaviour in the homepen was observed and three feather pecking tests were conducted as well: one individual test with a bunch of feathers (10 min) and two social tests (in random order), one with and one without a bunch of feathers (30 min with whole group). Observations focused on gentle and severe feather pecking, bunch pecking, ground pecking and preening. In the individual test, general activity and vocalisations were recorded as well, to measure the response to isolation. In general, HFP birds showed more gentle and severe feather pecking than LFP birds, whereas LFP birds showed more ground pecking and, unexpectedly, more bunch pecking. Birds that showed gentle feather pecking in the homepen also showed gentle feather pecking and bunch pecking in the social tests over all ages. Severe feather pecking in the social test with a bunch of feathers corresponded with severe feather pecking in the homepen. Bunch pecking in the individual test was not a reliable measure for feather pecking in this experiment. An increasing number of vocalisations in the HFP line and a decreasing number in the LFP line indicated a difference in reaction to the individual test. In conclusion, gentle and severe feather pecking and bunch pecking in the social test corresponded best with homepen behaviour, whereas bunch pecking in the individual test did not.

An experiment was carried out to study the lying postures, space occupation and percentage of space-sharing (as a consequence of huddling behaviour) in pigs. Information about these lying characteristics is essential for the calculation of lying space requirements, e.g. for pen design legislative purposes. The study included two replicates of eight groups of eight pigs each. Pigs were housed at thermoneutral conditions in 8 m(2) partly (40%) slatted pens from 25 to 100 kg live weight. Lights were on from 06:30 until 18:30 h. Feed and water were available ad libitum. Behaviour of the pigs was recorded for 48 h on video tape at approximately 30, 50, 80 and 100 kg live weight. General activity, lying posture (sternum, half recumbent, fully lateral recumbent) and space-sharing percentage were scored by 20 min scan sampling. The results confirmed that pigs of all weight categories lie down for a great part of the day: the average numbers of pigs that were lying were 83.8, 85, 86.3 and 87.5% at 30, 50, 80 and 100 kg live weight. Especially at night (18:30-06:30 h), the fully recumbent lying posture is predominant. The percentages of lying pigs that lied in the fully recumbent position in that period were 65.7, 66.4, 67.7 and 69.1 for 30, 50, 80 and 100 kg pigs, respectively. In our study, we observed that pigs spent little time in contact with conspecifics: space-sharing percentages were 20-40%. There was a significant period effect for the space-sharing data; pigs showed more 'social lying behaviour', i.e. tended to huddle more during the night in comparison to the day since the space-sharing percentages were higher during the night (P

Behaviour of broilers up to 6 weeks of age has been studied extensively, but little is known what happens after 6 weeks. Insight in the behavioural abilities after 6 weeks may also yield insight in the period before 6 weeks as the disbalance between motivation and physical abilities is more clearly elucidated with increasing weight. The purpose of this experiment was to investigate behaviour in fast- and slow growing broilers to 12 weeks of age and the physical consequences of the prolonged rearing period. Ninety-six 1-day-old female broiler chicks, 48 of a slow growing and 48 of a fast growing line were allocated to 16 floor pens (1.5 m(2) per pen): eight pens of six birds per line. Each pen contained perches and the floor was covered with wood shavings. One day per week, each bird was observed five times, distributed regularly over the day. Behaviour, posture (sitting or standing) and position (floor or perch) of each individual were recorded. After 12 weeks, the birds were killed and post-mortem examination was done to detect physical abnormalities. Fast- and slow growing broilers performed the same behavioural elements, but time budgets of fast- and slow growing broilers were different. Slow growing broilers perched, walked and scratched more than fast growing broilers. Fast growing broilers performed more sitting on the floor, eating and drinking than slow growing broilers. No differences were found for resting, preening, stretching, ground pecking or dust bathing. Time spent on several behaviours changed with increasing age or the posture during behaviour changed with age. Although several physical abnormalities were found in both lines, no correlation was found between physical abnormalities and behaviour. Physical abnormalities seemed not to be so severe to have hampered behavioural activity. The experimental conditions, such as only females, good quality of bedding, low stocking density, and perches seemed to be crucial to prevent serious physical abnormalities and to keep these birds to 12 weeks of age. This study showed that fast- and slow growing broilers are motivated to perform all kinds of behaviour in an environment where that is possible also after 6 weeks of age, but that the ability of performing some behaviours are more and more hampered with increasing age most probably due to their weight. (C) 2002 Elsevier Science B.V. All rights reserved.

Feather pecking is a major welfare and economic problem in laying hens. It is characterised by pecking at- and pulling out of feathers of conspecifics. A bird's propensity to develop feather pecking may be related with other behavioural characteristics, such as reaction to frustration (the omission of expected reward) and social motivation. Furthermore, differences in feather pecking between lines indicate that genetic background plays an important role.In this thesis, the relationship between feather pecking and other behavioural characteristics was studied in two lines that differed in feather pecking behaviour: the high (HFP) and low (LFP) feather pecking lines. The importance of the social environment was evaluated in an experiment where different tests to measure feather pecking were compared. Furthermore, the reaction to frustration was studied in these lines and it was studied whether frustration can facilitate feather pecking directly. In a behaviour genetics study, it was studied whether behavioural traits measured at young age were predictive of feather pecking at adult age.It was found that the social environment plays an important role in the development of feather pecking. Pecking at a bunch of feathers in an individual context is not comparable with feather pecking in a social group. Although HFP and LFP lines showed differences in reaction to frustration, short-term frustration in a Skinnerbox could not facilitate feather pecking. Finally open-field behaviour at young age was found to be predictive of pecking behaviour at adult age. These results were used to develop a model on the relationship between feather pecking and other behavioural characteristics, that may be helpful to solve the problem of feather pecking in laying hens.

The impact of environmental factors on immune responses may be influenced by coping characteristics of the individuals under study. The behavioral response of pigs in a so-called Backtest early in life seems indicative of their coping style at a later age. The present study investigated the effects of housing, barren versus enriched, and coping style, as assessed by Backtest classification, on immune responses of pigs. Pigs were housed either without a rooting substrate (barren housing) or in identical pens enriched with deep straw bedding (enriched housing) from birth. During the suckling period, pigs were subjected to the Backtest. Each pig was restrained on its back for 1 min and the resistance (i.e., number of escape attempts) was scored. Pigs classified as ‘high-’ or ‘low-resisting’ (HR and LR, respectively) were immunized with di-nitrophenyl-conjugated keyhole limpet haemocyanin (DNP-KLH) at 9 weeks of age. Blood samples were drawn before immunization (Day 0) and weekly thereafter, until Day 35. KLH-specific lymphocyte proliferation following immunization was higher for HR pigs than for LR pigs. Housing did not affect proliferative responses. Housing and coping style interacted in their effect on KLH-specific humoral immune responses. LR pigs from barren housing showed higher KLH-specific antibody titers than LR pigs from enriched housing. Differently housed HR pigs, however, showed similar antibody titers. These findings support other research indicating that individual coping styles of pigs are reflected in their immune responses. More important, the present study demonstrates that effects of housing on humoral immune responses of pigs may differ for pigs with divergent coping styles.

A test aiming to measure calves' responses to humans ("approach test") was conducted in two steps: during the first step (approach phase) the calves' reaction to the appearance of an unknown person (withdrawal or not) was observed during milk provision, during the second step (touch phase) the calves' reaction to the outstretching of the arm and touching on the head was measured qualitatively on a scale from I (no withdrawal) to 4 (strong withdrawal). The repeatability of the withdrawal test was determined by performing the test twice with a 2-day interval on 150 calves. The reliability of the test was determined by comparing the responses of 22 calves to the approach test with their behaviour to humans during a longer test in an arena. For the approach phase, a high consistency was found between repetitions: calves that withdrew from the unknown person during the first observation, withdrew again the next time. For the touch phase, calves with either score I or 4 had the same score the following observation. However, responses of score 2 or 3 were not very consistent over time. The scores obtained in both the approach and touch phase of the test were strongly related with the calves' responses to a person in an arena: calves who withdrew from the unknown person at the approach test showed a longer latency to interact, interacted less often and shorter with the unknown person when observed in the arena than did calves who did not withdraw. In conclusion, the approach test can be considered to be repeatable and reliable. Therefore, it can be used to determine the animal's responsiveness to humans. (C) 2003 Elsevier BX All rights reserved.

Feather pecking (FP) is a major problem in cage and free-range housing systems. In free-range systems, FP is more difficult to control. It is not known why a victim is being pecked. It could be that a bird is genetically predisposed to be pecked. To study the genetics of FP behavior, a large F2 population of 630 hens was generated from a cross between two commercial laying lines differing in their propensity to feather peck. The traits measured at 6 and 30 wk of age were receiving gentle FP, receiving severe FP, and receiving aggressive pecking. In addition, receiving toe pecking (TP) was also measured at 30 wk of age. For receiving gentle FP at 6 wk of age, a significant QTL on GGA1 and three different suggestive QTL were identified on GGA2, GGA6, and GGA7, respectively. For receiving gentle FP at 30 wk of age, a suggestive QTL on GGA5 was detected. For receiving aggressive pecking, a suggestive QTL was detected on GGA3. For receiving TP, three suggestive QTL were detected on GGA1, GGA5, and GGA23, respectively. The different QTL detected for receiving gentle FP at different ages indicate that this trait is regulated by different genes in young and adult hens.

Selection for a higher milk yield increases metabolic load via a higher yield per se and/or via physiological processes that facilitate milk yield, and it is difficult to differentiate between these two. Here, we aim to identify important pathways that contribute to the reduction in fertility following selection for higher yield. The associations between milk yield and fertility may run via pleiotropic effects, i.e. via functional pathways (for example related to intake), or linkage of genes and may involve changes in levels of hormones and metabolites. A number of studies have investigated the effects of genetic merit for milk yield on fertility, feed intake, energy balance and levels of metabolic and fertility hormones or metabolites. Differences in genetic merit were associated with differences in: (1) feed intake; (2) energy balance; and (3) plasma levels especially of GH, IGF-I, prolactin, progesterone, insulin, glucose, NEFAs and ketones. In the discussion we focus on the possible roles that energy balance, the growth hormone axis, and glucose together with insulin may have in the reduced fertility that is associated with high yield. The overall conclusion is that many minor pathways probably contribute, but that reduced metabolic fuel availability, rather than direct effects of hormone concentrations, is an important cause of poorer fertility with increasing genetic merit. (C) 2003 Elsevier B.V. All rights reserved.

1. It has been suggested that broiler chickens have a disturbed satiety and hunger mechanism. The satiety mechanism for eating can be expressed as the positive correlation between meal length and the length of the preceding ( preprandial) interval; the hunger mechanism for eating as the positive correlation between meal length and the length of the succeeding ( postprandial) interval. An experiment was conducted to investigate eating behaviour of male broiler and layer chickens by measuring meal and interval lengths. 2. Eight male broilers and 8 male layer chickens were housed individually and visually isolated in floor pens ( 1m(2)/ pen) on wood shavings. From 4 to 7 weeks of age, eating behaviour of each bird was recorded for 3 h in two conditions each week. In the first condition, the birds were not deprived from feed. In the second condition, they were 24-h food deprived and feed was provided just before the observation started. Preprandial and postprandial correlations were calculated based on data of the non-deprived condition. Before and after each observation bird and feeder were weighed to measure weight gain and feed consumption during observation. 3. Under the non-deprived condition, the broilers spent initially more, but at a later age less time on eating. The broilers had fewer meals per hour, consumed more feed per hour, and had longer meal and interval lengths than the layer chickens. After 24-h feed deprivation, the broilers had a longer first meal, consumed more feed per hour and spent more time on eating than the layer chickens. Significant preprandial correlations but no postprandial correlations were found in the broilers. In the layer chickens, both significant preprandial and postprandial correlations were found. This indicates that for regulating eating behaviour, the satiety mechanism dominates the hunger mechanism in broilers, and satiety and hunger mechanisms are equally involved in layer chickens. 4. The typical eating behaviour of broilers and the calculated preprandial and postprandial correlations have given new indications that hunger and satiety mechanisms in broilers have changed compared with layer chickens. In broilers, there is no lower set point, but only an upper set point for controlling eating behaviour, which suggests that broilers eat to their maximal physical capacity.

Reaction to frustration of high (HFP) and low feather pecking (LFP) laying hens was investigated. From a HFP- and a LFP-line five birds with a HFP- and five birds with a LFP-phenotype were selected. Birds from the HFP-line were expected to show more key pecking and covered feeder pecking during frustration than birds from the LFP-line. When a bunch of feathers was presented, birds with a HFP-phenotype were expected to redirect their pecks at the bunch. Birds were trained to peck a key for a food reward in an automated Skinnerbox and subjected to two sessions: a control session, where food was available, and a frustration session, where the feeder was covered with Perspex. These two sessions were repeated in the presence of a bunch of feathers. Unexpectedly, birds from the LFP-line had a stronger reaction to frustration than birds from the HFP-line, expressed in pecking behaviour. When a bunch of feathers was offered, birds with a HFP-phenotype did not show more bunch pecking during frustration than birds with a LFP-phenotype.

The problem of how to objectively assess the overall welfare status of animals under farming conditions has contributed to an ongoing debate that has hampered actual decision making on animal welfare. For this reason we constructed a model based on the assumed hierarchical organization of the animals’ needs for overall welfare assessment in the case of pregnant sows. This model is implemented in a computer-based decision support system that takes a description of a housing and management system as input and produces a welfare score as output. A formalized procedure was used to construct the model for welfare assessment in pregnant sows on the basis of available scientific knowledge. This SOWEL (from SOw WELfare) model contains 37 attributes that describe the welfare-relevant properties of housing and management systems. In the decision support system these attributes are linked to scientific statements and a list of needs to provide a scientific basis for welfare assessment. Weighting factors that represent the relative importance of the attributes are derived from the scientific statements about the various welfare performance criteria that have been measured by scientists. The welfare score is calculated as the weighted average score. All information in the decision support system is stored in tables in a relational database such that newly available knowledge and insights can be incorporated to refine the model. The model has been developed in line with several existing models but it differs from these models in that it is the first to provide a formalized procedure to explicate the reasoning steps involved in welfare assessment based on available scientific knowledge.

Previous research has shown that pre-parturient primiparous pigs (gilts) housed in behaviourally restrictive farrowing crates without straw redirect their nest-building behaviour to non-manipulable substrates such as the bars of the crate. These gilts also show elevated plasma adrenocorticotropic hormone (ACTH) and cortisol levels, particularly around the peak of nest-building activity, when compared to gilts in larger pens that have been provided with a manipulable substrate (straw). It remains unclear whether these behavioural and physiological responses to crating result from the lack of a suitable nesting substrate or from the restricted space. This study investigated the effects of space (crate [C] versus pen [P]) and straw (straw [S] versus no straw [NS]) using a 2 × 2 factorial design. Thirty-four gilts were implanted with an indwelling jugular catheter at around 12 days before parturition. They were moved to one of the four environments five days before parturition, and blood sampling and recording of behaviour were carried out during the pre-parturient period. Penned gilts (P), irrespective of straw availability, spent more time standing and walking and performed more total substrate-directed behaviour than crated (C) gilts. When straw was not available to penned gilts, a large proportion of their substrate-directed behaviour was redirected to the floor. Space also had an effect on ACTH and cortisol levels across the entire pre-parturient phase, with C gilts having higher levels than (P) gilts irrespective of straw availability, but particularly so at the peak of nest-building activity. There was no effect of straw on ACTH or cortisol levels. Overall, it appears that increased space, perhaps through allowing locomotion, increases substrate-directed behaviour of pre-parturient gilts. When space is available but straw is absent, pre-parturient gilts redirect their nest-building behaviour to the floor. The ability to express substrate-directed behaviour as a result of increased space is reflected in lower levels of indicators of physiological stress

'Welzijn bestaat niet', is een gevleugelde uitdrukking van één van mijn collega's. Deze weliswaar ietwat ongenuanceere stelling geeft het probleem weer waarmee een gedragsbioloog in het welzijnsonderzoek geconfronteerd wordt: welzijn is niet direct meetbaar. Want de aanname is dat een dier zelf uitmaakt hoe het met zijn welzijn gesteld is. Dat hangt af van de omstandigheden waarin het dier zich bevindt. Maar hoe komt een etholoog te weten hoe een dier de eigen situatie beoordeelt? Je kunt er niet naar vragen. Nou ja, je kunt er wel naar vragen, maar een antwoord zul je niet krijgen. Of misschien toch wel? Het promotie-onderzoek van Patrick Zimmerman richtte zich op de vraag of het welzijn van leghennen te meten is op basis van geluiden die ze maken

Bij legkippen ontwikkelt zich vaak verenpikken, het beschadigen of uittrekken van veren van soortgenoten, en soms ook kannibalisme, het verwonden van soortgenoten en het consumeren van bloed of vlees. Het uittrekken van veren levert pijn en ongemakt op voor het dier dat gepikt wordt. Het slachtoffer krijgt kale plekken op haar lichaam, hetgeen kan resulteren in problemen met de warmtehuishouding. Ook zijn de kale plekken aantrekkelijk voor soortgenoten om naar te pikken. Dit kan leiden tot ontwikkeling van kannibalisme, hetgeen gepaard gaat met een sterk verminderd welzijn en hoge uitvalspercentages. In het proces van domesticatie is de kip vanuit de vrije natuur naar het boerenerf verplaatst, vervolgens naar een afgesloten kippenren, en tenslotte naar de legbatterij, waar de dieren in kleine groepjes in kooien worden gehouden. Deze verhuizing van de vrije natuur naar de legbatterij heeft voor- en nadelen voor de kip gehad. Wat betreft de beschikbaarheid van voedsel en bijvoorbeeld bescherming tegen ziekte en predatie is de kip erop vooruit gegaan, maar wat betreft levensruimte en mogelijkheid tot het vertonen van het complete gedragsrepertoire, biedt de legbatterij weinig ruimte en mogelijkheden

Proceedings of the 36th international congress of the ISAE (International Society for Applied Ethology). Overviews are given of the given presentations, summaries, program overview, etc.