Jl McKinstry

Influence of housing system and design on bone strength and keel bone fractures in laying hens

The main objectives of the study were to provide an accurate assessment of current levels of old breaks in end-of-lay hens housed in a variety of system designs and identify the important risk factors. Sixty-seven flocks housed in eight broad subcategories were assessed at the end of the production period. Within each flock, the presence of keel fractures was determined and the tibia, humerus and keel bones dissected for measurement of breaking strength. For each house, variations in internal design and perching provision were categorised and the effective heights of the differing structures recorded. All systems were associated with alarmingly high levels of keel damage although variation in mean prevalence between systems was evident with flocks housed in furnished cages having the lowest prevalence (36 per cent) despite also having significantly weaker bones and flocks housed in all systems equipped with multilevel perches showing the highest levels of damage (over 80 per cent) and the highest severity scores.

Potential contamination of beef carcases with brain tissue at slaughter.

EXPERIMENTAL strain typing of variant Creutzfeldt-Jakob disease (VCJD) has shown that the transmissible agent responsible for this disorder is identical to that in bovine spongiform encephalopathy (BSE), providing further evidence to support the hypothesis that exposure to the BSE agent, presumably through the diet, is the cause of VCJD (Ironside 1998). Most cattle are stunned with a captive bolt gun (CBG) before slaughter and because of the suggested link between BSE and VCJD, the possibility that the use of CBGS may contaminate the carcase with brain tissue has raised concern for public health. Garland and others (1996) previously reported the finding, at necropsy, ofbrain tissue in the lungs of cattle slaughtered in the USA after being stunned with a pneumatically activated, penetrating CBG that introduced air intracranially. However, the validity and relevance of the Garland report was questioned (Taylor 1996) and similar studies carried out on 210 cattle in UK abattoirs failed to confirm this observation (Munro 1997). The UK Meat and Livestock Commission issued

Methods for detection of haematogenous dissemination of brain tissue after stunning of cattle with captive bolt guns.

Because of concern that the stunning of cattle with captive bolt guns (CBGs) could, if used on an animal with bovine spongiform encephalopathy (BSE), cause embolism of infective brain tissue and carcass contamination, the Ministry of Agriculture, Food and Fisheries commissioned research to assess the risk of haematogenous dissemination of CNS material after stunning. We have devised two methods to investigate this risk. The first involves the concentration of embolic tissue in buffy coat Cytoblocks that can be embedded for sectioning, microscopy and immunocytochemistry. The second method is an ELISA for the presynaptic protein, syntaxin 1B. The methods were validated by analysis of several bovine tissues, including blood samples deliberately contaminated with brain. We then studied jugular venous blood obtained before and after the stunning of 60 cattle with CBGs. Samples obtained, after stunning, from five of the cattle contained CNS tissue within the Cytoblocks and yielded positive syntaxin assays. Syntaxin was also detected in samples from one other animal that had been stunned with a pneumatically operated CBG. The described methods should allow an assessment of the risk of neuroembolism associated with different types of CBG and may also be useful in other contexts.

A bespoke management package can reduce levels of injurious pecking in loose-housed laying hen flocks.

This study investigated the protective effects of an on-farm management package designed to reduce injurious pecking (IP) in loose-housed laying hens. A systematic review of scientific literature generated 46 potentially protective management strategies. Bespoke management packages were designed for treatment flocks (TF) using these management strategies. IP in 53 TFs was compared with IP in 47 control flocks (CF) where the management package was not employed. Scoring of plumage damage (PD) and observations of gentle and severe feather pecking (GFP; SFP), and vent and cannibalistic pecking (VP) were completed, and management strategy use was recorded, at 20, 30 and 40 weeks of age. Differences between treatment and CF were examined using multilevel modelling. Compared with CF, TF employed more management strategies (P<0.001), had lower PD (P=0.003) and SFP (P=0.019). Regardless of treatment or control flock status, the more of the 46 management strategies that were employed the lower was the PD (P=0.004), GFP (P=0.021), SFP (P=0.043), mortality at 40 weeks (P=0.025), and the likelihood of VP (P=0.021). Therefore, the provision of a bespoke management package was protective against the majority of forms of IP in commercial laying hen flocks.

Jugular venous emboli of brain tissue induced in sheep by the use of captive bolt guns

Emboli of central nervous tissue were detected in the jugular venous blood of two of 15 sheep stunned with a conventional cartridge-operated captive bolt gun and in two of 15 sheep stunned with a pneumatically activated gun. No emboli were detected in arterial blood from these sheep or in venous blood from sheep stunned electrically. Emboli from an animal with BSE could transmit the disease to people.

Humane euthanasia of neonates I: validation of the effectiveness of the Zephyr EXL non-penetrating captive bolt euthanasia system on neonate piglets up to 10.9 kg live-weight

To determine if mechanical blunt force trauma using a non-penetrating captive bolt was a viable method of producing an immediate stun/kill in neonate piglets (Sus scrofa domesticus) as an alternative to manual blunt force trauma, piglets (n=60) were acquired from a local producer and allocated to one of 5 weight ranges Birth weight to 3 kg (n = 12), 3 to 5 kg (n = 11), 5 to 7 kg (n = 13), 7 to 9 kg (n = 13) and 9 to 11 kg (n = 11). These piglets, with an average liveweight of 6.1 kg, were anaesthetized and electroencephalogram (EEG) recording electrodes inserted subdermally over the right cranium to allow recording of Visual Evoked Potentials (VEPs). Following recording of baseline VEPs in the anaesthetized state the piglet was shot once in the frontal-parietal position with a Bock Industries Zephyr EXL non-penetrating captive bolt powered by 120 psi air pressure. Movement scoring, behavioural indices of loss of brain function and VEPs were monitored throughout. VEPs were lost immediately in all piglets shot when the head was resting on a hard surface. This experiment demonstrates that mechanical blunt force trauma using a single shot non-penetrating captive bolt, such as the Zephyr EXL, provides for an immediate stun kill in neonate piglets up to 10.9 kg liveweight. This immediacy of action, combined with reproducible effects will improve the welfare of piglets to be subjected to on-farm euthanasia due to disease, ill-thrift or other commercial concerns.

The evaluation of two commercial electric sheep stunning systems: current applied and the effect on heart function

The maintenance of head-only minimum stunning currents for sheep to ≥ 1.0 Amp as per current legislation was examined in two trials in a commercial abattoir. In the first trial, a Jetco MS100 stunner failed to maintain the current to > 1.0 Amp in 118 of the 228 sheep. In a second trial, a Jetco MS105 delivered sufficient current in all sheep (n = 275) to meet the legislative requirement, apart from a single animal. Recorded electrocardiograms showed a regular heartbeat, with no evidence of ventricular fibrillation, in all animals in both trials following stunning and neck-cut. Only one of the two stun units may therefore be considered to meet the statutory requirements but both may meet the requirements for halal slaughter where pre-stun is considered acceptable.

Government vets' involvement in veterinary education.

GOVERNMENT veterinary surgeons (GVS) have had considerable involvement in veterinary education at the schools of veterinary science within the UK. With funding from Defra, the University of Bristol has recently embarked on a research project to establish the extent of GVS staff involvement in veterinary education, its effectiveness and efficiency. This project will …