Parallel Sequencing Reveals Campylobacter spp. in Commercial Meat Chickens Less than 8 Days Old.

Campylobacter from contaminated poultry meat is a major source of human gastroenteritis worldwide. To date, attempts to control this zoonotic infection with on-farm biosecurity measures have been inconsistent in outcome. A cornerstone of these efforts has been the detection of chicken infection with microbiological culture, where Campylobacter is generally not detectable until birds are at least 21 days old. Using parallel sequence-based bacterial 16S profiling analysis and targeted sequencing of the porA gene, Campylobacter was identified at very low levels in all commercial flocks at less than 8 days old that were tested from the United Kingdom, Switzerland, and France. These young chicks exhibited a much greater diversity of porA types than older birds testing positive for Campylobacter by culture or quantitative PCR (qPCR). This suggests that as the bacteria multiply sufficiently to be detected by culture methods, one or two variants, as indicated by porA type, dominate the infection. The findings that (i) most young chicks carry some Campylobacter and (ii) not all flocks become Campylobacter positive by culture suggest that efforts to control infection, and therefore avoid contamination of poultry meat, should concentrate on how to limit Campylobacter to low levels by the prevention of the overgrowth of single strains. IMPORTANCE Our results demonstrate the presence of Campylobacter DNA among fecal samples from a range of commercially reared meat chicks that are less than 8 days of age, consistent across 3 European countries. The recently developed, sensitive detection method indicates that infection occurs on commercial farms much earlier and more widely than previously thought, which opens up new opportunities to control Campylobacter contamination at the start of the food chain and reduce the unacceptably high levels of human disease.

Early warning of footpad dermatitis and hockburn in broiler chicken flocks using optical flow, bodyweight and water consumption.

Footpad dermatitis and hockburn are serious welfare and economic issues for the production of broiler (meat) chickens. The authors here describe the use of an inexpensive camera system that monitors the movements of broiler flocks throughout their lives and suggest that it is possible to predict, even in young birds, the cross-sectional prevalence at slaughter of footpad dermatitis and hockburn before external signs are visible. The skew and kurtosis calculated from the authors' camera-based optical flow system had considerably more power to predict these outcomes in the 50 flocks reported here than water consumption, bodyweight or mortality and therefore have the potential to inform improved flock management through giving farmers early warning of welfare issues. Further trials are underway to establish the generality of the results.

Influence of rearing and lay risk factors on propensity for feather damage in laying hens.

1. Feather pecking is one of the major problems facing the egg industry in non-cage systems and is set to become even more of an issue with the European Union ban on the keeping of laying hens in barren battery cages which comes into force in 2012 and the prospect of a ban on beak-trimming. Reducing feather pecking without resorting to beak treatment is an important goal for the poultry industry. 2. We report here a longitudinal study that included over 335,500 birds from 22 free range and organic laying farms. Accelerated failure time models and proportional hazards models were used to examine the effects of a wide range of factors (management, environment and bird) on development of substantial feather damage in lay. Particular emphasis was placed on risk factors during rear and on practices that could feasibly be changed or implemented. 3. The age at which a flock exhibits substantial feather damage could be predicted both by factors in the environment and by early symptoms in the birds themselves. Factors that were associated with earlier onset of severe feather damage included the presence of chain feeders, raised levels of carbon dioxide and ammonia, higher sound and light levels, particularly in younger birds. Increased feather damage (even very slight) in birds at 17-20 weeks of age was also highly predictive of the time of onset of severe feather damage during lay. Increased feed intake also indicated that a flock was at risk of early severe feather damage. 4. Birds that stayed on the same farm for rearing and lay showed later onset of serious feather damage than those that experienced a change in farm from rearing to lay. However, an increased number of changes between rearing and lay (feeder type, drinker type, light intensity etc) was not associated with earlier onset of serious feather damage. Further research needs to be done on the role of the transition from rearing to lay as a risk factor for FP in lay.

Effect of environment on Pekin duck behaviour and its correlation with body condition on commercial farms in the UK.

1. Forty-six flocks of commercially-reared Pekin ducks were studied to determine the effects of housing system and environment on the behaviour of farmed ducks and its correlation with physical condition. Houses differed predominantly in their ventilation, drinking, feeding and brooding systems, and were indicative of systems currently in use in the UK. 2. At 41 d of age ducks spent 15% of the time feeding, 67% drinking, 42% rooting and 155% dry preening. They spent large amounts of time relatively inactive, 435%, or performing comfort behaviours, 17%. On average 46% of their time was spent walking and only 18% wet preening. 3. A greater proportion of the maximum number of ducks able to use the drinker at any one time used the trough; nipple use was least and Plasson use intermediate. The proportion of ducks wet preening was not affected by drinker type but increased with increasing drinker space (mm/bird). 4. Duck behaviour was little affected by commercial production system and was influenced more by environment, age and physical condition. Activity at an older age incorporated more of the behaviours associated with thermal comfort (panting) and maintenance of plumage condition (dry and wet preening). These behaviours increased with increasing temperature, relative humidity and atmospheric ammonia. Poor walking ability was correlated to increased frequency of panting, reduced activity at the drinker, and longer resting bouts.

Environment and management factors affecting Pekin duck production and welfare on commercial farms in the UK.

1. Forty-six flocks of commercially-reared Pekin ducks were studied in 23 houses differing in their ventilation and brooding systems, and water and feed resources, in order to identify factors affecting duck welfare in commercial practice. 2. A wide range of environmental variables were measured, together with the physical and plumage condition of the ducks at two ages, whilst companies supplied mortality and growth rate data. 3. At 23 d, more than 98% of ducks had clean eyes, nostrils and feathers and an upright posture, and 86% had no gait abnormalities. By 41 d, body condition had deteriorated slightly with 84% of ducks having clean eyes, 67% clean feathers and 79% no gait abnormalities. 4. Gait worsened with increasing temperature and litter moisture, and atmospheric ammonia concentrations. The incidence of foot pad lesions was 10% (moderate) and 3% (severe) and was positively correlated with increasing humidity and ammonia. 5. Average mortality rates were 52% for ducks reared to 335 kg at 48 d with average growth rates of 603 to 813 g/d. High temperatures correlated with high mortality and reduced growth rate; growth rate was not related to poor gait. 6. Controlling the ducks' environment, particularly temperature, humidity, litter moisture and ammonia is crucial to duck welfare. Effective ventilation systems, high quality straw and access to some form of open water were considered important for duck welfare.

Environmental and management factors affecting the welfare of chickens on commercial farms in the United Kingdom and Denmark stocked at five densities.

Data from a large commercial-scale experiment in which 10 major broiler producer companies stocked whole houses of birds at 30, 34, 38, 42, and 46 kg/m2 were analyzed to identify 1) temperature and humidity profiles achieved throughout the growth cycle, 2) management practices and equipment that contributed to observed variation in environmental conditions, and 3) the extent to which environmental variables affected bird welfare. The study involved a total of 2.7 million birds in 114 houses on commercial farms with measurement of a wide range of environmental and bird variables. Much of the variation in broiler health and welfare was associated with the percentage of time a company could maintain house temperature and RH within limits recommended by the breeder company. RH in the first week of life was particularly important to later health, suggesting that better control of humidity might lead to improved welfare. Key management factors affecting bird welfare were those relating to good ventilation and air control such as the type of ventilation, type of drinker, numbers of stockmen, and litter type. Controlling the environment, particularly temperature, humidity, and air and litter quality, is crucial to broiler chicken welfare. This does not mean that stocking density is unimportant, but lowering stocking density on its own, without regard to the environment the birds experience, is not sufficient. Genuine improvements in bird welfare will come from setting standards that combine stocking density, safeguards on the environment, and the genetic makeup of the birds.

Pattern recognition and active vision in chickens.

Recognition of objects or environmental landmarks is problematic because appearance can vary widely depending on illumination, viewing distance, angle of view and so on. Storing a separate image or 'template' for every possible view requires vast numbers to be stored and scanned, has a high probability of recognition error and appears not to be the solution adopted by primates. However, some invertebrate template matching systems can achieve recognition by 'active vision' in which the animal's own behaviour is used to achieve a fit between template and object, for example by repeatedly following a set path. Recognition is thus limited to views from the set path but achieved with a minimal number of templates. Here we report the first evidence of similar active vision in a bird, in the form of locomotion and individually distinct head movements that give the eyes a similar series of views on different occasions. The hens' ability to recognize objects is also found to decrease when their normal paths are altered.

Predator discrimination error and the benefits of Müllerian mimicry.

Müllerian mimicry has traditionally been thought to benefit both unpalatable mimic and model species but recently its existence has been questioned. Even if both mimic and model species are unpalatable, they are unlikely to be equally unpalatable. It has been argued that the more unpalatable species will suffer a cost of increased predation because the presence of the more palatable mimic will increase its perceived palatability (by the predator), similar to that experienced by a model in Batesian mimicry. Yet, previous models of Müllerian mimicry have assumed that a predator can discriminate perfectly between available prey. We argue that this is not the case and that discrimination error is an important factor in determining the nature of mimetic relationships. Using computer simulations we show that the nature of a mimetic relationship will depend on the trade-off between the cost of an increase in perceived palatability and the benefits of a reduction in predator discrimination error. We show that mimicry can be unequivocally Müllerian, with both species benefiting, and propose that palatability should no longer be used as the sole defining characteristic of a mimetic relationship. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Evolution and animal welfare.

Animal welfare is a topic often thought to reside outside mainstream biology. The complexity of the methods used to assess welfare (such as health, physiology, immunological state, and behavior) require an understanding of a wide range of biological phenomena. Furthermore, the "welfare" of an animal provides a framework in which a diversity of its responses can be understood as fitness-enhancing mechanisms. Different methods for assessing animal welfare are discussed, with particular emphasis on the role of an animal's own choices and reinforcement mechanisms. No part of biology is as yet able to explain consciousness, but by confronting the possibility that nonhuman animals have conscious experienced of suffering, animal welfare studies force a consideration of even this hardest problem of all biological phenomena in a particularly direct and evolutionary way.

Dermatomyositis: a dermatology-based case series.

BACKGROUND: Dermatomyositis is associated with significant morbidity and occasional mortality. Currently there is no consensus on treatment for patients with dermatomyositis. OBJECTIVE: Our purpose was to review the clinical features and response to therapy of patients with dermatomyositis and compare these data with previous series of patients with dermatomyositis/polymyositis. METHODS: Clinical characteristics of 65 patients seen during a 10-year period were reviewed retrospectively. Twenty-one of these patients were enrolled in a prospective, uncontrolled study of treatment with high-dose prednisone followed by slow tapering. RESULTS: Clinical features were similar to those previously described; however, muscle strength at diagnosis was on average greater in patients in this series than in patients previously reported. Malignancy was present in 5 of 43 adult patients (12%), but was not found in patients with juvenile dermatomyositis. Another connective tissue disease was present in 19% of patients. Twelve patients had dermatomyositis sine myositis. Eighteen of 21 patients (85%) in the prednisone study group had resolution of myositis. CONCLUSION: Patients with dermatomyositis in this series had less active myositis at presentation, but were otherwise similar to patients with dermatomyositis/polymyositis previously reported. Treatment with high-dose daily prednisone followed by slow tapering was effective.

Cognitive ecology: the evolutionary ecology of information processing and decision making.

edited by Reuven Dukas, University of Chicago Press, 1998. $95.00/£75.95 hbk, $30.00/£23.95 pbk (x+420 pages) ISBN 0 226 16932 4 (hbk), 0 226 16933 2 (pbk).

Distance and the presentation of visual stimuli to birds

Artificial visual stimuli in the form of photographs, video sequences and computer-generated images are increasingly being used to explore the visual world of birds but their use is controversial as it is still not clear whether birds see them in the same way that humans do. While differences between bird and human colour vision may be one problem with using such artificial images, another and potentially even more important difficulty is the distance at which stimuli are presented. An experiment is described in which hens, Gallus gallus domesticuswere trained to move towards one of two real objects viewed at two different distances. Even for real objects, discrimination levels were better when the hens were allowed to view the stimuli from 5-25 cm than when they were forced to choose at 120 cm and this correlated with their ability to transfer to photographs of the same objects at different distances. In a colour discrimination at a short distance, five out of seven hens showed 100% correct responses when first shown photographs of real objects that they had previously learnt to discriminate. The results suggest that photographs can be used as substitutes for real stimuli but that care should be taken over the distance at which they are presented. The results are discussed in relation to the visual behaviour of birds and differences in functioning of their frontal and lateral visual fields.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour

Drug use and violent crime among adolescents.

This study examines the extent to which alcohol and other drug use is related to violent and nonviolent criminal activity among adolescents males. Based on data collected from 312 youthful offenders at a public juvenile facility, the findings reveal that in comparison to marijuana and heroin, alcohol use is more strongly and consistently associated with both violent and nonviolent offenses. When other factors are introduced into the analysis, the results show that while an adolescent's criminal history and racial identity are relatively more important in predicting criminal activity overall, the effect of substance use (especially alcohol and marijuana) continues to be present.

Peck orders and group size in laying hens: `futures contracts' for non-aggression.

We analyse a simple model of the establishment and maintenance of dominance hierarchies in hens. To be beneficial, dominance relationships require that the probability of meeting the same individual repeatedly is high, otherwise costs of establishing the dominance relation are never recouped. Winners and losers benefit from dominance relationships, not necessarily from changing the rate at which they acquire resources but by avoiding costly contests over them in future encounters. We show that so-called `loser effects', in which animals base their strategies for contesting resources solely upon their past experiences of winning or losing dominance fights and not upon who their opponent is, cannot work - these strategies (`pragmatists') must additionally involve either individual or status category recognition. As alternatives to dominance relationships, we show that signals of status or fighting ability that determine access to contested resources are expected to evolve in species with typically large groups because in such conditions the costs of establishing dominance relations are not recouped. Such signals do not depend upon recognizing others individually, but rather upon general category recognition. Status signals are not expected in small groups because dominance relationships are likely to be cheaper and just as effective. The results of the model have implications for the welfare of hens kept in large groups.

Discrimination and recognition of photographs of places by homing pigeons.

Operant studies on pigeons using slide-projected images suggest that photographs of geographical locations might be used as a research tool to study the importance of visual landmarks in homing. Before using this method, however, it is necessary to show that pigeons do see photographic slides as representing real world locations. After reviewing the evidence for picture-to-object correspondence for geographical locations in pigeons, we report the results of an experiment designed to test whether outdoor experience at a location affected homing pigeons' ability to categorise slides of that versus another location displayed in an operant set-up. Four birds visited one location immediately before each experimental session; four birds visited an irrelevant location. No effect of outdoor experience was found on acquisition, or transfer to novel stimuli. The possible reasons for limitations on picture-to-object correspondence are discussed.

An exaggerated preference for simple neural network models of signal evolution?

Recently, simple neural network models have been used to explain the evolution of important phenomena in animal signalling, such as extravagant ornamentation and symmetrical signals, as responses to inevitable 'hidden preferences' of recognition systems. We argue that these very simple models may be misleading because they may not behave in important ways like the recognition systems of real animals and so cannot justify their claim to demonstrate general principles of perception in a signalling context. We show that the way in which these simple models respond to exaggerated signals may not be, as is claimed, a close parallel to the phenomena of peak shift or supernormal responses. We also argue that the preference for symmetrical patterns shown by the models is unlikely to reflect the way computationally that real animals solve problems of pattern invariance and may be an artefact of the particular way the models have been set up. Whereas more sophisticated neural net models do capture known properties of real visual systems and are consequently of great use in understanding perception, the same cannot be said of very simple one-dimensional models with small numbers of units and connections. Given the far reaching explanatory claims made of these simpler models their limitations should be more widely recognized.