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The organisation of animal populations in social groupings may play a crucial role in the transmission of any infectious disease that requires close contact. The objective of this study was to quantify the contact structure of part of the Heck cattle population in a Dutch nature reserve and its hypothetical effect on the transmission of bovine herpesvirus 1 (BHV1). The contact structure was quantified by observing the number of different animals with whom contact was made (i.e. the number of contactees) within a fixed time period. Two types of behaviour sampling methods, namely focal sampling and scan sampling were used to observe the contact structure. In this study only those contacts between individuals were observed that were assumed to be a proxy measure of an at-risk event for BHV1-infection. Two reproduction ratios (R), i.e. the average number of new cases caused by a typical infected individual, were estimated, one for the observed contact structure and another for a random mixing contact structure. The two reproduction ratios were then compared to study the hypothetical effect on BHV1 transmission. The overall number of contactees was highest during summer and lowest during winter-spring. The contact structure of the homogeneous population did differ significantly from a random mixing contact structure, resulting in that the variation in the number of contactees was higher than under random mixing. Bulls, young bulls and cows had the highest number of contactees during, respectively, summer, autumn and winter-spring. From the analysis of the contingency tables it was clear that contacts between animal types did not occur at random during summer and autumn. For example, during summer more contacts than expected occurred between bulls and cows. This heterogeneity at animal type level was taken into account in the calculation for R, which resulted for the observed contact structure in higher estimates for R than for the homogeneous population. When looking at heterogeneity at individual level it was found that during summer almost all individuals were observed together direct or indirect in the same group except for certain bull groups. During autumn and winter-spring almost all individuals were seen together in the same group when considering a long contact period of 14 days but the groups were fallen apart in smaller groups and solitary individuals for a short contact period of 5 days. It could be concluded that based on the observed contact structure transmission would be favoured most during summer.

Prenatal stress is known to affect several offspring characteristics, but its effects depend among other factors on the period of gestation in which it is applied. In the present study, oral administration of hydrocortisone-acetate (HCA) was used to elevate cortisol concentrations in pregnant sows to levels also observed after psychological stress. HCA was administered during three different periods of gestation (115 days in pigs): period 1: 21¿50 (P1, n = 10), period 2: 51¿80 (P2, n = 10) and period 3: 81¿110 (P3, n = 10) days after insemination. Control sows (n = 11) received vehicle from 21¿110 days after insemination. When P1-, P2- and P3-sows did not receive HCA, they also received vehicle. During gestation, weekly saliva samples were taken from the sows to determine salivary cortisol concentrations. Treatment effects on sow, litter and piglet characteristics were determined. In addition, two female piglets per litter were subjected to an ACTH-challenge test at 6 weeks of age to determine the adrenocortical response to ACTH. Pigs were slaughtered at 6 months of age and slaughter weight, back fat thickness and percentage of lean meat were analysed. During the period of treatment with HCA, salivary cortisol concentrations were increased in P1-, P2- and P3-sows compared to control sows (P 0.30), but pooled HCA-litters had a higher percentage of live born piglets (P

Several behavioural effects of prenatal stress are reported in literature, and these seem to depend, among other factors, on the gender studied and the period of gestation in which prenatal stress is applied. In the present study, oral administration of hydrocortisone-acetate (HCA) to 41 pregnant sows was used as a model for prenatal stress, since corticosteroids are considered a key mediator in the effects of prenatal stress. HCA was orally administered to pregnant sows during three periods of gestation: 21-50 (period 1, P1, n = 10), 51-80 (period 2, P2, n = 10) and 81-110 (period 3, P3, n = 10) days after insemination (term 115 days). Control sows (n = 11) received vehicle from 21 to 110 days after insemination. Between days 9 and 48 after birth, treatment effects on male and female piglet behaviour were determined in the home pen and in four different behavioural tests. During the backtest, no gender differences were observed in vocalisations in HCA-piglets, while control males vocalised more than control females. In the home pen at 14 days of age, HCA-piglets spent less time in social interactions than control piglets. During the novel environment test, P1- and P3-piglets walked more than control piglets, but this was not observed during the novel object test, four days later. At weaning, P2- and P3-piglets performed less individual play. Prior to mixing with an unfamiliar piglet (male piglets only), HCA-piglets had lower salivary cortisol concentrations than control piglets, but no difference was observed after mixing. P1-, P2-, and P3- piglets had fewer non-aggressive encounters, and P2-piglets continued fighting longer than control piglets. The present study demonstrates that elevated maternal cortisol concentrations during gestation affect piglet behaviour, and effects do differ between male and female piglets. In addition, effects depend on the period of cortisol administration.

Improved housing for laying hens may start from the translation of their behavioral needs into welfare-based design parameters for laying hen houses. The objective of our research was to gain insights into the facility usage and behavioral needs of the hen over 24 h when there are no obvious restraints. Twenty ISA Brown commercial laying hens (Gallus domesticus) that were 18 wk old and not beak trimmed, were accommodated in a pen (4 x 6 m) at 19 + 2 degrees C on a light-dark cycle of 10L:14D. The pen providing nest boxes, drinkers, feeders, perches, sand, and wood shaving was designed to accommodate the hens for the experimental period. Video recordings were made for 10 d. Behavioral analyses were conducted on 5 birds for 5 d. Time spent on each behavior, log survivor analysis of events and inter-event intervals, bout analysis, diurnal pattern in events and bouts, occurrence of behavior in different segments and the corridor of the pen, and sequence analysis were performed to gain insights into the temporal and sequential structures of behavior. Hens spent 97% of the day on nest use, preening, drinking, feeding, still, walking, perching, and resting; 43% on commodity-dependent behavior; and 57% not on commodity-oriented behaviors. Behavioral events were short (around 70% event2 min) and frequent (around 70% inter-event intervals40s). The pen corridor was the preferred place for attack, escape, flying, resting, walking, and wing flapping. Feeding-drinking-feeding, preening-resting-preening, scratching-resting-scratching, dust bathing-resting-preening, or dust bathing-resting-wing stretching-dust bathing were the preferred sequences of behavior. Although hens interrupted ongoing behaviors and changed behaviors frequently, they nonetheless clustered behavioral events.

The object of this research was to study the relationship between feather pecking and open-field activity in laying hens at two different ages. A population of 550 birds of a laying hen cross was subjected to an open-field test at 5 and 29 weeks of age and to a social feather pecking test at 6 and 30 weeks of age. Factor analysis was used to identify underlying factors for each test: pecking behavior ( social test) and open-field activity (open-field test). In young birds, a positive phenotypic correlation of 0.24 was found between high open-field activity and high levels of pecking behavior ( ground pecking, preening, gentle feather pecking, and wall pecking). In adults, a similar genetic correlation of 0.62 was found. At adult age, the factor pecking behavior consisted mainly of gentle and severe feather pecking. Between ages, a strong, negative genetic correlation of - 0.65 was found between open-field activity at young age and pecking behavior at adult age, indicating that open-field activity levels in young birds may predict pecking behavior in adult hens.

Poor physical abilities of broilers may prevent them from performing behaviours for which they are motivated. The aim of this study was to measure the influence of physical ability and motivation on the performance of broilers in short physical tasks. We tested birds from a fast- and a slow-growing broiler strain in a runway to 12 weeks of age. To manipulate motivation, half of the birds of each strain was feed deprived for 3 h and the other half for 24 h before testing. Each bird was tested in a control and a slalom runway test once a week. With a similar motivation, slow growers had a shorter latency to start walking and walked faster through the runway than fast growers in both tests. In fast growers walking speed decreased faster with age than in slow growers. Slow growers vocalised more in both tests. In the slalom test, 24 h deprived birds vocalised more than 3 h deprived birds. Although the fast and slow growers have a different genetic background, the results indicated that motivation is the dominant determinative factor for walking in birds with a low body weight, while physical ability is the dominant determinative factor for walking in birds with a high body weight.

Several recent studies in juvenile pigs demonstrated a relationship between the degree of resistance displayed early in life in a so-called "backtest" and parameters of cell-mediated and humoral immunity. Some of the immune characteristics were reported to depend on the interaction between backtest classification and housing system. In the present study, the effects of backtest classification and housing condition on immune reactivity in adult gilts were examined. 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) or low resisting (LR) were selected and housed in groups of six gilts. At 7 months of age, half of the gilts were housed in individual stalls. At 12 months of age, gilts were challenged by immunization with DNP-KLH. Control gilts were treated similarly with a placebo. Blood samples were drawn prior to immunization (Day 0) and weekly thereafter until Day 28. No significant effects of backtest type on cellular and Immoral responses against KLH were found. Furthermore, being housed in stalls as compared to groups had no consequences for the immune response and did not induce differences between HR and LR gilts. Differences in behavior and physiology found previously between HR and LR gilts, particularly in gilts in stall housing, may thus be of relatively little importance for immune-related health. (C) 2003 Elsevier Inc. All rights reserved.

Both restricted feeding and barren housing have a negative influence on sow welfare. The aim of this study was to test whether sows that have to search for their feed in a substrate on the floor show less stereotyped (and other abnormal) behaviour and have a lower physiological stress response. In three batches, 96 gilts were housed individually in two rooms in 3.1 m2 pens with 1.9 m2 solid floor. In a 2×2 factorial design either wood shavings (S) or no substrate (NS) were provided on the floor, and 900 g of feed was provided twice daily (06:30 and 15:00 h) either in a trough (T) or on the floor (F). In weeks 8–12, behaviour was scan-sampled once in the periods 07:00–09:00 h (P1), 10:00–12:00 h (P2), and 13:00–15:00 h (P3). Data from the 5 weeks were pooled per animal. Video recordings (24 h) in week 12 or 13 were scan-sampled for ‘standing’. Saliva samples were taken in week 11 at 2 h intervals during 24 h and measured for cortisol. Spontaneously voided morning-urine was sampled in weeks 2, 7 and 12 or 13 for determination of ratios of adrenaline (A) and noradrenaline (NA) with creatinine (CR). Most effects that were found were due to substrate presence. Main findings were that compared with S-animals, NS-animals stood more during the dark period (4.8% versus 3.0%; P

In the European Union, legislation concerning animal housing is becoming stricter because of animal welfare concerns. Feather pecking (FP) in large group housing systems is a major problem. It has been suggested that corticosterone (CORT) response to manual restraint as a measure for stress is associated with FP behavior. The aim of the current study was to identify QTL involved in FP behavior and stress response in laying hens. An F-2 population of 630 hens was established from a cross between two commercial lines of laying hens differing in their propensity to feather peck. The behavioral traits, measured at 6 and 30 wk of age, were gentle FP, severe FP, and aggressive pecking. Toe pecking was measured at 30 wk of age and CORT response to manual restraint was measured at 32 wk. All animals were genotyped for 180 microsatellite markers. A QTL analysis was performed using a regression interval mapping method. At 6 wk of age, a suggestive QTL on GGA10 was detected for gentle FP. At 30 wk of age, suggestive QTL were detected on GGA1 and GGA2 for gentle FP. A significant QTL was detected on GGA2 for severe FP. At 32 wk of age, a suggestive QTL was detected on GGA18 for CORT response to manual restraint. In addition, a suggestive QTL was detected on GGA5 with possible maternal parent-of-origin effect for CORT response.

Background The decline noticed in several fertility traits of dairy cattle over the past few decades is of major concern. Understanding of the genomic factors underlying fertility, which could have potential applications to improve fertility, is very limited. Here, we aimed to identify and study those genes that associated with a key fertility trait namely estrous behavior, among genes expressed in four bovine brain areas (hippocampus, amygdala, dorsal hypothalamus and ventral hypothalamus), either at the start of estrous cycle, or at mid cycle, or regardless of the phase of cycle. Results An average heat score was calculated for each of 28 primiparous cows in which estrous behavior was recorded for at least two consecutive estrous cycles starting from 30 days post-partum. Gene expression was then measured in brain tissue samples collected from these cows, 14 of which were sacrificed at the start of estrus and 14 around mid cycle. For each brain area, gene expression was modeled as a function of the orthogonally transformed average heat score values using a Bayesian hierarchical mixed model. Genes whose expression patterns showed significant linear or quadratic relationships with heat scores were identified. These included genes expected to be related to estrous behavior as they influence states like socio-sexual behavior, anxiety, stress and feeding motivation (OXT, AVP, POMC, MCHR1), but also genes whose association with estrous behavior is novel and warrants further investigation. Conclusions Several genes were identified whose expression levels in the bovine brain associated with the level of expression of estrous behavior. The genes OXT and AVP play major roles in regulating estrous behavior in dairy cows. Genes related to neurotransmission and neuronal plasticity are also involved in estrous regulation, with several genes and processes expressed in mid-cycle probably contributing to proper expression of estrous behavior in the next estrus. Studying these genes and the processes they control improves our understanding of the genomic regulation of estrous behavior expression.

The sow's breeding value for mothering ability (EBVma) can be estimated as the genetic effect of the foster sow on piglet survival at weaning. Sows with a high EBVma have litters with a short average interval from birth until first colostrum intake. In the present study, it was investigated whether sows with a high EBVma show differences in maternal behaviour during parturition. It was hypothesized that during parturition, sows with a high EBVma and/or weaning survival were less active (increased durations of lying laterally and lying ventrally, decreased durations of standing and sitting and less postural transitions) than sows with a low EBVma. These behaviours were observed from birth of first piglet until birth of last piglet using 25 sows with known EBVma. It was found that during parturition sows with high weaning survival showed longer durations of sitting and shorter durations of standing than sows with low weaning survival. These results indicate that maternal behaviour during parturition has an effect on piglet survival at weaning. No effect of EBVma on maternal behaviour during parturition was found. In conclusion, EBVma of sows did not show a relationship with their maternal behaviour during parturition. This would suggest that the previously found difference in interval until first colostrum intake of piglets from sows with varying EBVma, is not related to differences in maternal behaviour during parturition, although this should be specifically tested in future experiments. The results from this study can be used as a starting point for future research to eventually provide breeding companies with tools to select sows for pre-weaning survival of piglets.

Improving dairy cow fertility by means of genetic selection is likely to become increasingly important, since it is now well established that declining fertility cannot only be arrested by improved management. Profit margins per kg milk produced are decreasing, therefore farmers need to reduce cost and increase herd size. This restricts the labor input per cow and the disposable cost of getting a cow pregnant, whilst at the same time hormone treatments have become less acceptable. This makes it unlikely that additional management interventions will maintain fertility at acceptable levels in the near future. Genetic improvement seems the obvious solution. Effective selection tools are available in most Western countries using traditional breeding value estimation procedures. Also, in addition to gene assisted selection using individual genes or QTL, high throughput Single Nucleotide Polymorphism (SNP) technology allows genetic improvement of fertility based on information from the whole genome (tens of thousands SNP per animal), i.e. genomic selection. Simulation studies have shown that genomic selection improves the accuracy of selecting juvenile animals compared with traditional breeding methods and compared with selection using information from a few genes or QTL only. Research in the areas genomics and proteomics promise to make genetic selection even more effective. The genomic and proteomics technologies combined with the bioinformatics tools that support the interpretation of gene functioning and protein expression facilitate an exciting starting point for the development of new management strategies and tools for the improvement of reproductive performance.

International audience; Measuring HPA axis activity is the standard approach to the study of stress and welfare in farm animals. Although the reference technique is the use of blood plasma to measure glucocorticoid hormones (cortisol or corticosterone), several alternative methods such as the measurement of corticosteroids in saliva, urine or faeces have been developed to overcome the stress induced by blood sampling itself. In chronic stress situations, as is frequently the case in studies about farm animal welfare, hormonal secretions are usually unchanged but dynamic testing allows the demonstration of functional changes at several levels of the system, including the sensitization of the adrenal cortex to ACTH and the resistance of the axis to feedback inhibition by corticosteroids (dexamethasone suppression test). Beyond these procedural aspects, the main pitfall in the use of HPA axis activity is in the interpretation of experimental data. The large variability of the system has to be taken into consideration, since corticosteroid hormone secretion is usually pulsatile, follows diurnal and seasonal rhythms, is influenced by feed intake and environmental factors such as temperature and humidity, age and physiological state, just to cite the main sources of variation. The corresponding changes reflect the important role of glucocorticoid hormones in a number of basic physiological processes such as energy metabolism and central nervous system functioning. Furthermore, large differences have been found across species, breeds and individuals, which reflect the contribution of genetic factors and environmental influences, especially during development, in HPA axis functioning. Usually, these results will be integrated with data from behavioral observation, production and pathology records in a comprehensive approach of farm animal welfare.

Each year, millions of dogs worldwide are abandoned by their owners, relinquished to animal shelters, and euthanised because of behaviour problems. Nutrition is rarely considered as one of the possible contributing factors of problem behaviour. This contribution presents an overview of current knowledge on the influence of nutrition on canine behaviour and explores the underlying mechanisms by which diet may affect behaviour in animals. Behaviour is regulated by neurotransmitters and hormones, and changes in the availability of their precursors may influence behaviour. Tryptophan, the precursor of serotonin, may affect the incidence of aggression, self-mutilation and stress resistance. The latter may also be influenced by dietary tyrosine, a precursor to catecholamines. As diet composition, nutrient availability and nutrient interactions affect the availability of these precursors in the brain, behaviour or stress resistance may be affected. PUFA, especially DHA, have an important role as structural constituents in brain development, and dietary supply ofn-3 andn-6 PUFA could modify aspects of the dopaminergic and serotonergic system and, consequently, cognitive performance and behaviour. Finally, persistent feeding motivation between meals can increase stereotyped behaviour and aggression and decrease resting time. This feeding motivation may be altered by dietary fibre content and source. At present, few studies have been conducted to evaluate the role of nutrition in canine (problem) behaviour through the above mentioned mechanisms. Studies that explore this relationship may help to improve the welfare of dogs and their owners.

High milk production in dairy cattle can have negative side effects on health and fertility traits. This paper explores the genetic relationship of milk yield with health and fertility depending on herd environment. A total of 71,720 lactations from heifers calving in 1997 to 1999 in the Netherlands were analyzed. Herd environment was described by 4 principal components: intensity, average fertility, farm size, and relative performance indicating whether herds had good (poor) health and fertility despite a high (low) production. Fertility was evaluated by days to first service and number of inseminations (NINS); somatic cell score was used as a measure of udder health. Data were analyzed with a multitrait reaction norm model. Genetic correlation within traits across environments ranged from 0.84 to unity. Genetic correlations of the 3 traits with milk yield were antagonistic but varied over environments. Genetic correlation of milk yield with days to first service varied from 0.30 in small herds to 0.48 in herds with low average fertility. Correlations with NINS varied from 0.18 in large herds to 0.64 in high fertility herds, and with somatic cell score from 0.25 in herds with a high fertility relative to production to 0.47 in herds with a relative low fertility. Selection in environments of average value resulted in different predicted responses over environments. For example, selection for a decrease of NINS of 0.1 in an average production environment decreased milk yield by 35 kg in low production herds, but by 178 kg in high production herds.

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.

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.

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

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.

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.

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.

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.

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.

A study was conducted to compare activity, oral behaviour and slaughter data of veal calves kept in three different housing systems: (1) individual housing (IH) where calves are kept in individual crates; (2) group housing (GH) where calves are kept in individual crates during the first 8 weeks and thereafter in groups of five to seven individuals, and (3) Peter's Farm ® (PF) a housing system where calves are kept in large groups fed via an automatic feeding station. Six commercial farms with Holstein–Friesian bull calves for each housing system were selected ( n =18). Behavioural observations were done at weeks 2, 3, 6, 12 and 24 after arrival of the calves at the farm to measure time budget in the morning and 30min after feeding, and 24h activity. All farms were assessed by the animal needs index (ANI) at week 12. The 24h activity pattern of calves in IH and in GH showed peaks around feeding time. The activity of calves in PF was distributed equally over the day. Calves in PF were standing less and lying more ( P P P P P P Overall, the measured parameters gave some indication that welfare has improved in PF during the first 6 weeks of life. At a later age, these parameters indicated that in PF a similar welfare existed as in IH and GH. Food but not housing conditions seems to be the determinative factor at that age. IH and GH were not different for many parameters.

The possible advantage of using multiple phospho-specific antibodies to study changes in brain activity was assessed. For this purpose, rats were injected intraperitoneally with either a control treatment or 15 mg/kg pentylenetetrazol. The sub-convulsive dose of pentylenetetrazol did not induce marked behavioural effects. Ten minutes after treatment, the rats were perfused and the brains were dissected. Adjacent brain sections were immunohistochemically stained for phosphorylated cyclic-AMP response element-binding protein and phosphorylated mitogen-activated protein kinase. Opposite effects of pentylenetetrazol treatment were observed on the immunoreactivity of these two antibodies within the hypothalamic paraventricular nucleus, the supraoptic nucleus and the arcuate nucleus. In these regions, pentylenetetrazol treatment increased phosphorylated mitogen-activated protein kinase immunoreactivity, but decreased phosphorylated cyclic-AMP response element-binding protein immunoreactivity. These findings show that changes in the activity of a brain nucleus can be accompanied by differential changes in the activity of two signal transduction pathways, which can be detected immunohistochemically. Therefore, the use of multiple phospho-specific antibodies may enhance our potential to monitor changes in brain activity.

In order to keep a high level of welfare an animal has to interact with the environment. Predictability and controllability of environmental stimuli seem to be of major importance. Loss of predictability and loss of controllability have a detrimental effect on animals. We hypothesised that both loss of predictability and loss of controllability would, among other behavioural effects of frustration, lead to an increase in the number of gakel-calls in laying hens. The gakel-call, expressed during the thwarting of behaviour, presumably is an indicator of frustration in laying hens. Predictability of reward was offered by a classical conditioning procedure, controllability of reward by operant conditioning. Assuming that controllability is predictability plus added control we also hypothesised that loss of controllability would lead to higher levels of gakel-calls than loss of predictability. Twenty hens of two commercial strains of laying hens, 10 ISA Brown Warrens and 10 ISA White Leghorns, were used. These strains of hens are known to differ in their reaction to frustration. They were subjected to frustration during a classical and an operant conditioning situation in a counterbalanced design. We found that in both conditioning situations the hens gave more gakel-calls in the frustration treatment than in the control treatment. No difference in levels of gakel-calls during frustration between classical and operant conditioning was found. Both loss of predictability and loss of controllability seem to impair a laying hen's welfare. The results suggest that the strains differ in behavioural strategy during frustration. When using the gakel-call as measure for welfare this difference in behavioural strategy should be taken into account.

Multiparous sows that had been tethered during lactation were put in two different housing conditions after weaning (Day 0); the sows were either tethered by neck chain, or individually housed in a pen of approximately 6 m2. After two months, ten tethered and eleven loose housed sows were used to assess stress and reproductive parameters. Stereotypic behaviour after the afternoon feeding was assessed from Day 18 onwards; at Day 53 stereotypic behaviour tended to occur during a higher percentage of time in the tethered sows (P = 0.11) and at Day 66, the differences were significant (tethered, 78 +/- 5 vs. loose-housed, 40 +/- 10% of time (mean +/- sem); P = 0.03). At Day 35 and 55, cortisol profiles after afternoon feeding were similar for the two groups of sows (P > 0.10). Around oestrus (approximately Day 64), the profiles of oestradiol-17 beta, luteinizing hormone and progesterone were measured and proved to be similar for both treatment groups (P > 0.10). The duration of oestrus was shorter in the tethered sows (42 +/- 4 vs. 63 +/- 2 h; P < 0.001) and, consequently, the timing of ovulation during oestrus (h after onset of oestrus) was advanced in the tethered sows (28 +/- 2 vs. 41 +/- 2; P < 0.001). The duration of ovulation did not differ (tethered, 2.9 +/- 0.5 vs. loose-housed, 2.1 +/- 0.2 h; P = 0.16). The sows were sacrificed at Day 5 after ovulation; ovulation rate, fertilization rate, embryo development and embryo diversity were similar for the two groups, as were adrenal weight and size of adrenal cortex. Duration of oestrus and the levels of stereotypies at Day 60 tended to be negatively related in the tethered sows (P = 0.07), but not in the loose-housed sows (P = 0.65). In conclusion, sows that had been tethered during pregnancy and lactation, and were housed loose or were tethered again at weaning within two months differed both in stereotypic behaviour and in duration of oestrus, without apparent effects on reproductive hormones.