Comparison of the welfare of layer hens in 4 housing systems in the UK.

1. The welfare of hens in 26 flocks (6 conventional cage, 6 furnished cage, 7 barn, 7 free-range) was assessed throughout the laying period using a combination of data on physical health, physiology and injurious pecking, collected by researchers on farm and during post-mortem analysis, and information submitted by producers. 2. There was an effect of housing system on 5 of the indicators recorded by researchers: gentle feather pecks given, feather damage score, proportion of hens with feather damage, proportion of the flock using perches, and faecal corticosterone. 3. Post-mortem analysis revealed several differences between housing systems in skin damage, plumage damage to the vent and abdomen, keel protrusion, bodyweight, and the proportion of hens that were vent pecked and that had old and recent keel fractures. 4. There was an effect of housing system on 5 indicators recorded by producers: proportion of egg shells with calcification spots, proportion of egg shells with blood stains, weight of hens found dead, temporal change in the proportion of egg shells with stains, and temporal change in proportion of hens found dead. 5. Each housing system had positive and negative aspects but overall, hens in barn systems had the highest prevalence of poor plumage condition, old fractures, emaciation, abnormal egg calcification, and the highest corticosterone. Hens in conventional cages sustained more fractures at depopulation than birds in other systems. Vent pecking was most prevalent in free-range flocks. The lowest prevalence of problems occurred in hens in furnished cages. 6. Although housing system had an influence on the hens' physical condition and physiological state, the high prevalence of emaciation, loss of plumage, fractures and evidence of stress is of concern across all housing systems, and suggests that the welfare of modern genotypes is poor.

Dynamic induction of the long pentraxin PTX3 in the CNS after limbic seizures: evidence for a protective role in seizure-induced neurodegeneration.

Pentraxin 3, a prototypic long pentraxin, is induced by proinflammatory signals in the brain. Inflammatory cytokines are rapidly induced in glia by epileptic activity. We show that pentraxin 3 immunoreactivity and mRNA are enhanced in the rat forebrain above undetectable control levels by limbic seizures with a dual pattern of induction. Within 6 h from seizure onset, pentraxin 3 immunoreactivity was increased in astrocytes. Eighteen to 48 h later, specific neuronal populations and leucocytes were strongly immunoreactive only in areas of neurodegeneration. This staining was abolished when neuronal cell loss, but not seizures, was prevented by blocking N-methyl-D-aspartate receptors. Pentraxin 3 -/- mice had a more widespread seizure-related neuronal damage in the forebrain than their wild-type littermates although both groups had similar epileptic activity. Our results provide evidence that pentraxin 3 is synthesized in brain after seizures and may exert a protective role in seizure-induced neurodegeneration.

Inter-dog aggression in a UK owner survey: prevalence, co-occurrence in different contexts and risk factors.

Aggression between dogs is common and can result in injury. The aims of this study were to estimate prevalence, evaluate co-occurrence with human-directed aggression, and investigate potential risk factors, using a cross-sectional convenience sample of dog owners. Aggression (barking, lunging, growling or biting) towards unfamiliar dogs was reported to currently occur, by 22 per cent of owners, and towards other dogs in the household, by 8 per cent. A low level of concordance between dog and human-directed aggression suggested most dogs were not showing aggression in multiple contexts. Aggression towards other dogs in the household was associated with increasing dog age, use of positive punishment/negative reinforcement training techniques, and attending ring-craft classes. Aggression towards other dogs on walks was associated with location of questionnaire distribution, owner age, age of dog, origin of dog, dog breed type, use of positive punishment/negative reinforcement training techniques and attending obedience classes for more than four weeks. In both, the amount of variance explained by models was low (<15 per cent), suggesting that unmeasured factors mostly accounted for differences between groups. These results suggest general characteristics of dogs and owners which contribute to intraspecific aggression, but also highlight that these are relatively minor predictors.

Pop hole use by hens with different keel fracture status monitored throughout the laying period.

The aim of this work was to study the effect of keel fractures on the extent to which free-range hens access the range through pop holes. Over two consecutive laying periods (two production years) a total of 1100 individual birds from one half of a house, divided into four separated flocks, were caught at 25, 35, 45, 55 and 65 weeks, palpated to assess the prevalence and severity of keel fractures and tagged with RFID transponders. Their use of pop holes was subsequently monitored in some cases from week 25 to end of lay at 68 to 70 weeks. At regular intervals (every 10 weeks), the tagged birds were re-caught to assess changes in keel fracture prevalence and severity. The average percentage of birds with fractured keels at 25, 35, 45, 55, 65 and at end of lay (68 to 70 weeks of age) was 5.5, 25.5, 49, 63, 66.5 and 78.5, respectively, across both production years. The effect of keel score on pop hole use was modelled statistically, adjusting for weather conditions and age of the birds. There were significant effects of most of the weather variables recorded, as well as age of the bird, on use of pop holes and also a significant effect of keel score. Higher keel scores resulted in a reduction in pop hole use. A significant statistical interaction between keel score and ambient temperature revealed an accelerated reduction in use as the temperature decreased and keel score increased. It is concluded that the occurrence of keel fractures may affect the birds' ability or willingness to utilise the outdoor range provided by free-range housing systems, thereby reducing the potential welfare advantages of this type of housing.

Evaluation of the microclimate in poultry transport module drawers during the marketing process of end-of-lay hens from farm to slaughter.

Changes in module drawer temperature and relative humidity were monitored for 24 commercial loads of hens. Mathematical models revealed significant differences in predicted drawer temperature depending on their location and the outside environmental temperature. Higher predicted temperatures were found in uppermost drawers of the top modules at the front of the lorry, and lower temperatures in drawers on the outer sides of modules and in those drawers in modules next to the back of the lorry in both the upper and lower modules during transport. In the lairage, drawer temperature generally decreased, except in drawers at the top of modules where temperatures increased. Temperature increases were most often recorded in modules which had been located at the rear of the lorry, which were generally cooler during transport. End-of-lay hens would appear to be exposed to a greater risk of cold stress rather than heat stress in the UK. Inspection of birds during transport, or upon arrival, should be directed to the bottom and side drawers of a load when looking for cold stress, and the top row of drawers (centre) of the top modules when looking for heat stress. The frequency of inspections should increase at times of high ambient temperature while the birds are being held in lairages. Adjusting the numbers of birds loaded per drawer according to bird condition and weather appears to be an effective mitigation strategy which is already in use commercially.

Levels of mortality in hens by end of lay on farm and in transit to slaughter in Great Britain.

The average mortality for end of lay hens dead on arrival (DOA) was 0.27 per cent (median 0.15 per cent) in a survey of 13.3 million hens transported during 2009. A statistical model of the data indicated main risk factors for DOA to be slaughter plant, distance travelled and external air temperature, with longer journeys and low external air temperatures increasing the risk. Other highly significant risk factors (P<0.001) related to the condition of the birds on farm, where an increased risk of DOA was positively associated with poor feather cover, lower body weight, cumulative mortality of the flock and poor health (indicated by a high proportion of the load rejected at the plant for traumatic injury and disease state). However, the data indicate that by taking risk factors into consideration it is possible to transport hens up to 960 km with low losses in temperate conditions. Mean levels of on-farm mortality, during the laying period, for a total of 1486 flocks were significantly lower in cages (5.39 per cent) than in barn (8.55 per cent), free-range (9.52 per cent) or organic flocks (8.68 per cent) according to producer records a median of seven days before depopulation, with considerable variation between flocks in all systems.

Use of radiography to identify keel bone fractures in laying hens and assess healing in live birds.

The aim of this study was to use radiography to assess and characterise naturally occurring keel bone fractures in laying hens and monitor live birds over several weeks to examine the healing process. Twenty-four Lohmann brown commercial laying hens with varying degrees of keel bone fracture were used in the study. Birds were radiographed regularly over six weeks and the radiographic features and changing appearance of keel bone fractures were evaluated. The radiographic characteristics of old and new fractures were categorised and indicated that 80 per cent of birds entering the study with new fractures had healed after 35 days and five birds had incurred new fractures irrespective of their original fracture status.

Continuous monitoring of pop hole usage by commercially housed free-range hens throughout the production cycle.

Free-range laying hens are able to move between the indoor house and range through exits termed pop holes. The aim of this study was to examine the proportion of the flock that used the pop holes and to identify patterns of movement throughout the flock cycle. Four flocks of free-range hens each of 1500 birds were studied. Ten per cent of each flock were tagged with RFID (radio-frequency identification) transponders and their pop hole activity studied throughout the production cycle. Within two weeks of tagging at 25, 35, 45, 55 and 65 weeks of age, approximately 80 per cent of the tagged birds were seen in the pop holes and 50 per cent of the tagged birds were seen on 80 per cent of the days available to them after tagging. Within the flock, subpopulations of birds could be identified: those that never ventured to the pop holes (approximately 8 per cent), those that used the pop holes very infrequently (approximately 8 per cent), those that sat in the pop holes (approximately 4 per cent), and those that used the pop holes frequently (approximately 80 per cent). There was an effect of age of the birds, time of day and daily mean temperature on pop hole usage. Additional factors affecting activity on particular days were wind speed, rainfall and hours of sunshine. The findings show that a significant proportion of the flock accesses the pop holes on a regular basis with only a very small proportion preferring to stay in the house.

Identification and expression cloning of a leptin receptor, OB-R.

The ob gene product, leptin, is an important circulating signal for the regulation of body weight. To identify high affinity leptin-binding sites, we generated a series of leptin-alkaline phosphatase (AP) fusion proteins as well as [125I]leptin. After a binding survey of cell lines and tissues, we identified leptin-binding sites in the mouse choroid plexus. A cDNA expression library was prepared from mouse choroid plexus and screened with a leptin-AP fusion protein to identify a leptin receptor (OB-R). OB-R is a single membrane-spanning receptor most related to the gp130 signal-transducing component of the IL-6 receptor, the G-CSF receptor, and the LIF receptor. OB-R mRNA is expressed not only in choroid plexus, but also in several other tissues, including hypothalamus. Genetic mapping of the gene encoding OB-R shows that it is within the 5.1 cM interval of mouse chromosome 4 that contains the db locus.