Commercial slaughter methods used on Atlantic salmon: determination of the onset of brain failure by electroencephalography

This study investigated the effect of exsanguination without prior stunning, or carbon dioxide narcosis followed by exsanguination, or percussive stunning or spiking the brain, on the time taken to abolish the visual evoked responses (VERS) of farmed Atlantic salmon. Only percussive stunning and spiking killed the fish immediately and the other two methods resulted in aversive reactions by the fish. The VERS were lost between 148 and 440 seconds after exsanguination without stunning, and between 300 and 554 seconds after carbon dioxide narcosis followed by exsanguination. During both these procedures the fish showed strong aversive behaviour. In contrast, percussive stunning and spiking the brain could result in the immediate loss of VERS and no aversive reactions from the fish if the stun was applied correctly.     

Longer journeys to processing plants are associated with higher mortality in broiler chickens.

1. The number of broilers recorded as dead on arrival (DOA) in 1113 journeys to a poultry processing plant was related to the length of the journeys. The average journey time was 3.3 h and the maximum recorded was 9 h. 2. Overall, 0.194% of 3.2 million birds were DOA. Mortality was higher for journeys which took longer. For journeys lasting less than 4 h the incidence of dead birds was 0.156%; for longer journeys the incidence was 0.283%. 3. There was some evidence that it was time of journey, rather than distance travelled, that was more important in determining mortality.     

Evaluation of effectiveness and efficiency of wild bird surveillance for avian influenza

This study aimed to assess which method of wild waterbird surveillance had the greatest probability of detecting highly pathogenic avian influenza (HPAI) H5N1 during a period of surveillance activity, the cost of each method was also considered. Lake Constance is a major wintering centre for migratory waterbirds and in 2006 it was the site of an HPAI H5N1 epidemic in wild birds. Avian influenza surveillance was conducted using harmonised approaches in the three countries around the lake, Austria, Germany and Switzerland, from 2006–2009. The surveillance consisted of testing birds sampled by the following methods: live birds caught in traps, birds killed by hunters, birds caught in fishing nets, dead birds found by the public and catching live Mute Swans (Cygnus olor); sentinel flocks of Mallards (Anas platyrhynchos) were also used. Scenario tree analysis was performed including sensitivity analysis, followed by assessment of cost-effectiveness. Results indicated that if HPAI H5N1 was present at 1% prevalence and assuming HPAI resulted in bird mortality, sampling dead birds found by the public and sentinel surveillance were the most sensitive approaches despite residual uncertainty over some parameters. The uncertainty over the mortality of infected birds was an influential factor. Sampling birds found dead was most cost-effective, but strongly dependent on mortality and awareness of the public. Trapping live birds was least cost-effective. Based on our results, we recommend that future HPAI H5N1 surveillance around Lake Constance should prioritise sentinel surveillance and, if high mortality is expected, the testing of birds found dead.     

Duration of wing flapping in chickens shackled before slaughter

Shackling can induce wing flapping in chickens. In this survey of 30 chicken processing plants the proportion of birds flapping their wings had usually subsided to less than 0.5 per cent after the birds had been conveyed 2 m away from the shackling area. Thereafter, there were many causes of wing flapping, of which the following were thought to be important; tight fitting shackles on the birds' shanks, electric shocks at the water bath stunner before stunning, sudden bright sunlight, bends in the line, temporary loss of visual contact between neighbouring birds, and unevenness in the line which jolted the birds. If it is decided that legislation is required to prescribe a minimum 'hang-on' period before stunning it is suggested that birds should not be put through the stunner less than 12 seconds after shackling because after this time 99.7 per cent of the birds had stopped flapping.     

Causes of trauma in broilers arriving dead at poultry processing plants.

A post mortem examination was made on 1324 broiler carcases which arrived dead after being transported to six processing plants. The carcases were dissected and evaluated for trauma and obvious cause of death. Of the birds sent to the plants on the day of collection 0.19 per cent arrived dead and 35 per cent of these were thought to have died as a result of trauma. Haemorrhage associated with dislocation of the femur at the hip was the most common cause of trauma. Ruptured livers and crushed heads were other important traumatic injuries.     

The effects of two non‐steroidal anti‐inflammatory drugs on the mobility of laying hens with keel bone fractures

ObjectiveInvestigate the effects of administration of meloxicam and carprofen on the mobility of hens with and without keel fractures.Study designWithin each of two experiments a ‘blinded’ randomised cross over design whereby birds received either the test drug (carprofen or meloxicam) or saline.AnimalsTwo groups of Lohman Brown hens with and without keel bone fractures.MethodsThe first group (n = 63) was treated with carprofen 25 mg kg⁻¹ and saline subcutaneously, twice. The second group (n = 40) was treated with meloxicam (5 mg kg⁻¹) and saline subcutaneously. The latency of birds to fly down from perches 50, 100 and 150 cm above the ground was measured after each treatment. Data from experiment 1 and 2 were analysed separately; the effects of drug treatment compared with saline on landing time for birds with and without keel bone fractures were evaluated using MLwiN.ResultsIn both experiments latency to fly down from perches was longer in hens with keel fractures and there was a significant interaction between perch height and fracture status. For carprofen, at the 50 cm, 100 cm and 150 cm perch heights, birds with fractures took (mean ± SD) 2.5 ± 2.9, 6.8 ± 9.7 and 11.5 ± 13.2 seconds respectively to fly down compared with 1.3 ± 0.5, 2.3 ± 1.2 and 4.2 ± 3.1 seconds for birds without fractures. For meloxicam, at the 50 cm, 100 cm and 150 cm perch heights, birds with fractures took 2.9 ± 2.5, 49.8 ± 85.4 and 100.3 ± 123.6 seconds respectively compared with 0.7 ± 0.5, 2.5 ± 7.1 and 3.0 ± 4.6 seconds to fly down for birds without fractures. There was no significant effect of carprofen or meloxicam treatment.Conclusion and clinical relevanceThese data provide further confirmation that keel fractures reduce the willingness of birds to move from perches.     

Salmonella enterica subspecies enterica serotype Typhimurium and Escherichia coli O86 in wild birds at two garden sites in south-west Scotland

Salmonella enterica subspecies enterica serotype Typhimurium and Escherchia coli O86:K61:NM are two bacteria that can cause outbreaks of mortality in garden birds visiting bird tables and other feeding stations. Two sites in south-west Scotland were monitored for the two organisms for 12 months. At site A, large numbers of birds fed throughout the year, and at site B smaller numbers of birds fed only in the winter months. Samples of composite faeces were collected from the feeding stations and screened for the organisms, and any dead birds were also screened. S Typhimurium definitive type (DT) 56 (variant) was found to be endemic at site A, and was recovered from 48 per cent of samples of composite faeces collected from the bird table, from 42 per cent of composite faeces from underneath a hanging feeder, and from 33 per cent of composite faeces from below a roost used by house sparrows; the organism was also isolated from the carcases of six wild birds found dead at the site. In contrast, S Typhimurium (DT41) was recovered only once at site B, from 2 per cent of the composite faeces from below a hanging feeder, and no dead birds were recovered from the site. E coli O86 was not recovered from the faeces collected from either site, but was isolated from a bird that died from trauma at site A.     

Behavioural responses of poultry during kosher slaughter and their implications for the birds' welfare

Measurements were made during Shechita (kosher) slaughter of 692 meat chickens, including the behaviour of the birds during the procedure and the times from their removal from the crate, to neck cutting, bleed-out and shackling. Four of 100 birds showed a mild physical response to neck cutting but the others showed no response. Approximately 60 per cent of the birds showed a physical response to touching the eye or eyelid at up to 5 seconds after neck cutting, but by 15 seconds none showed this response. The birds became unable to retain their posture and suffered involuntary muscular contractions at 12 to 15 seconds after neck cutting and had lost approximately 40 per cent of their total blood volume by 30 seconds after neck cutting.     

Slaughter methods: electroencephalographic (EEG) studies on spinal cord section, decapitation and gross trauma of the brain in lambs

By means of electroencephalograms (EEG), attempts were made to determine when insensibility could be presumed in five lambs, two subjected to immobilisation by the punctilla method, two decapitated and one shot by a captive bolt in the poll region. Section of approximately 80% of the spinal cord by the punctilla method had no apparent effect on sensibility and the technique was considered to be inhumane. The EEG obtained from a decapitated bead showed no obvious change in pattern for eight seconds and subsequent changes were similar to those associated with exsanguination only. Thus no evidence was obtained to indicate that decapitation causes immediate insensibility, neither was the belief substantiated that severance of the spinal cord, during the slaughter of sheep, hastens the onset of insensibility. These results also provide additional evidence on the inhumane nature of punctilla slaughter of cattle. The animal shot with a captive bolt in the poll region, as opposed to the frontal region, showed EEG activity for 78 seconds.     

Necrotic Enteritis in Broiler Chickens II. Pathology and Proposed Pathogenesis

The intestines from 124 dead, sick and normal broiler chickens from 24 cases of necrotic enteritis were subjected to histological examination. Tissue sections from the duodenum, jejunum, ileum and ceca from each broiler were examined histologically for lesions of necrotic enteritis and the presence of coccidia. Lesions of necrotic enteritis were present in one or more areas of the intestine in all but six of 94 dead or sick birds and they were most common and severe in the jejunum. Coccidia were found in only small numbers in both diseased and normal birds.

Brown and Brenn stained sections showed Gram-positive bacilli intimately associated with early necrotic lesions on the tips of villi. Tissue sections from the intestines of sick birds permitted a proposed pathogenesis for this disease with the lesion starting at the tips of villi.

The similarity in pathogenesis and pathological lesions in this disease of broilers and Clostridium perfringens type C enteritis in baby pigs is discussed.

     

The effect of the duration and type of stress on some serum enzyme levels in pigs.

The effects of blood sampling from the ear vein, jugular vein and collection on exsanguination, on serum CK, LDH, GOT and PK activities were investigated. The activities of LDH and PK were higher in ear vein vena cava samples. The effect of pre-slaughter handling was also investigated. In general there was a significant progressive increase in serum enzyme activities from farm to slaughter, although the magnitude of the change varied for different enzymes.     

An Outbreak of Marek's Disease in Chickens in Central Ethiopia

A study was conducted on an outbreak of Marek's disease in a commercial poultry farm containing 8500 chickens in central Ethiopia. On repeated visits, farm and flock history was collected, sick birds were examined and clinical signs and daily mortality were recorded. A total of 80 (27 sick and 53 dead) birds 12-22 weeks old, were collected, autopsied and examined. The mortality rate was 46% for the first 14 weeks of the outbreak. Acute and chronic (classical) forms of the disease, the respective occurrence of which varied significantly (p<0.01) in young (14.6% vs 85.4%) and adults (48.7% vs 51.31%) were manifested. All the autopsied birds had gross and microscopic lesions indicative of Marek's disease in the peripheral nerve(s) and/or visceral organs. Lesions involving peripheral nerves and visceral lymphomas were recorded mainly in adults (28/35, 80%) and young birds (34/45, 75%), respectively. These differences in the two age groups were statistically significant (p<0.01). Young birds seem to be highly susceptible to the acute disease. Poor management, overstocking and lack of vaccination might have favoured the outbreak. Marek's disease causes considerable economic loss and is a major threat to poultry production in Ethiopia. This report emphasizes that Marek's disease should be considered as a disease of economic significance in chicken production in Ethiopia and warrants due attention.     

DIELDRIN POISONING AND BOTULISM IN AUSTRALIAN PELICANS (PELECANUS CONSPICILLATUS)

SUMMARY Autopsies and laboratory examinations of material from 24 Australian pelicans found sick or dead in southern coastal Queensland in 1977 to 1979 revealed dieldrin poisoning in 8 from the Brisbane region and botulism in 8 from Brisbane. Bundaberg and Gladstone. In those diagnosed as dieldrin poisoning, brain and liver samples contained 12.1 to 27.4 and 34.0 to 48.1 mg/kg dieldrin respectively. All of these birds were emaciated, 2 had convulsed and 1 had muscle tremors. Low and probably insignificant residues of DDE were detected in many birds. Type C botulism was confirmed in 4 of the 6 birds tested with specific antiserums. A large number of parasites including mites, lice, nematodes, cestodes, trematodes, coccidia and Sarcocystis sp were found but were thought to have had only a limited effect on the health of these birds.     

First report of an infectious bursal disease outbreak in a vaccinated chicken flock in Anambra State, Nigeria.

Infectious bursal disease was reported in a flock of 7-week old vaccinated chickens. Clinical findings and post-mortem changes were classical as well as the microscopic pathology of the bursa. Bursal homogenates from dead birds were positive for IBD virus antigen in agar gel diffusion test (AGDT). Convalescent sera obtained from birds 14 days following the onset of clinical signs were also positive for IBD virus antibody in AGDT. Seven-week old susceptible birds, each infected i/m with 0.1 ml of a bursal preparation from the outbreak, showed clinical signs of IBD on the 3rd day and were all dead by the 6th day. Their bursae were also positive for IBD virus antigen in AGDT. This is the first recorded outbreak of IBD in Southern Nigeria following inoculation with a locally produced vaccine.     

A geographic study of West Nile virus in humans,dead corvids and mosquitoes in Ontario using spatial scan statistics with a survival time application

Surveillance of West Nile virus (WNv) in Ontario has included passive reporting of human cases and testing of trapped mosquitoes and dead birds found by the public. The dead bird surveillance programme was limited to testing within a public health unit (PHU) until a small number of birds test positive. These dead corvid and mosquito surveillance programmes have not been compared for their ability to provide early warning in geographic areas where human cases occur each year. Spatial scan statistics were applied to time‐to‐event survival data based on first cases of WNv in found dead corvids, mosquitoes and humans. Clusters identified using raw data were compared to clusters based on model‐adjusted survival times to evaluate whether geographic and sociodemographic factors influenced their distribution. Statistically significant (p < .05) space–time clusters of PHUs with faster time to detection were found using each surveillance data stream. During 2002–2004, the corvid surveillance programme outperformed the mosquito programme in terms of time to WNv detection, while the clusters of first‐positive mosquito pools were more spatially similar to first human cases. In 2006, a cluster of first‐positive dead corvids was located in northern PHUs and preceded a cluster of early human cases that was identified after controlling for the influence of geographic region and sociodemographic profile.     

An evaluation of the effectiveness of handheld stunners for stunning chickens

Two experiments were conducted in which the spontaneous physical behaviour, spontaneous electroencephalogram (EEG) and somatosensory evoked potentials were examined in chickens stunned with a handheld, head-only stunner operating at 117 v. Thirteen of 14 birds lost their evoked potentials after stunning, and when they were exsanguinated within 15 seconds they did not regain them before they died. The remaining bird appeared to have evoked potentials after stunning but there was a movement artifact in its EEG and it is possible that they were not genuine responses. When head-only stunning was applied to 50 birds for one second the birds appeared to be stunned instantaneously, in terms of their spontaneous physical behaviour. However, they recovered more rapidly than 40 birds which were stunned for seven seconds. It was concluded that the handheld stunner can stun a bird effectively, and provided that the bird's neck is cut promptly, can kill it humanely.     

禽流感病毒番鸭分离株对不同禽类致病性的研究

将禽流感病毒番鸭分离株ZM的感染性鸡胚尿囊液静脉或肌肉接种不同禽类,同时设鸡源JC株对照,以了解毒株的致病特点。结果显示ZM株与同期分离JC株致病能力相当,两毒株均对鸡、鹅、番鸭、鹌鹑和鹧鸪显示了很强的致病能力,致死率50％-100％,死亡禽类的肝、肾、肺、脾、胰腺等多个组织器官均存在严重的损伤。鸽子,肉鸭和绍鸭(除zM株致死一只绍鸭外)均未发生死亡,外观健康。     

Effect of carprofen on lameness in broiler chickens.

Lameness is prevalent among broiler chickens and there is concern that it is chronically painful. The administration of an analgesic has been frequently used to identify pain in lame farm animals. Therefore, in this study the ability of lame and normal broiler chickens to traverse an obstacle course was tested after treatment with the analgesic, carprofen, a placebo saline injection or a control handling procedure. Sound birds traversed the course in approximately 11 seconds, irrespective of treatment. Lame birds took approximately 34 seconds to traverse the course, unless they received carprofen, which reduced their completion time to 18 seconds. Thus, carprofen substantially increased the speed of lame birds, providing evidence that birds with moderate lameness suffer pain when they walk.     

Carcase downgrading of broiler chickens

1. Data were collected (1981‐82) from four commercial processing plants in different states of Australia. Total downgrading was classified into damage occurring on the farm, bruising and processing plant damage.

2. The average proportion of birds downgraded each day (TDG) for the four plants varied from 9·6 to 15·7% of production and the largest component was the proportion bruised (3·5 to 8·0% of daily production).

3. The distribution of bruises was similar for the four plants, with breast and leg bruises predominating.

4. There was no correlation between the processing plant line speed and the TDG.

5. No correlation was found between the Performance Indication Factor, a measure of efficiency of food utilisation, and the TDG.

6. Records were available for 77 flocks processed over two consecutive working days. Correlation was low (r = 045) between the TDG for the first and the second day's processing suggesting that farm practices were unlikely to affect the incidence of bruising.