This study assessed the welfare of rats (Rattus norvegicus) poisoned with a lethal dose of the methaemoglobin (MetHb) inducing compound para-aminovalerophenone (PAVP). Twenty rats were orally gavaged with either PAVP (treated) or the vehicle only (control). Spontaneous and evoked behaviours were recorded and blood samples collected post mortem for analysis of MetHb%. Female and male rats received a mean (± SEM) dose of 263 (± 3) and 199 (± 6) mg PAVP kg−1, respectively. Mean (± SEM) time to death was 67 (± 16) and 354 (± 71) min for female and male rats, respectively. Control animals did not show any signs of intoxication. The time to death from methaemoglobinaemia in rats was significantly shorter than that reported for anticoagulants and there were no obvious signs of distress or pain.

The study examined cattle farmers' and veterinarians' opinions of pain-induced distress associated with disbudding and attitudes towards non-steroidal anti-inflammatory drugs (NSAIDs). An emphasis was placed on investigating pain perception, veterinary-client communication and factors influencing analgesic use. Data were collected from an online questionnaire, links to which were published in professional periodicals, promoted by industry organisations and distributed on private practice mailing lists. A total of 110 veterinarians and 116 farmers who regularly disbud calves completed the questionnaires. Of the respondents, 56% of veterinarians and 14% of farmers routinely use NSAIDs for disbudding. Respondents perceived disbudding to be severely painful without medication and 82% of veterinarians and 43% of farmers perceived post-procedural pain to persist beyond 24 h. There was a significant difference between female and male veterinarians' pain scores for disbudding without medication. Veterinarians underestimate the influences of welfare and analgesic duration and effectiveness on farmers' decisions and overrated cost impact. The study highlights that improvements in veterinarian-farmer communication regarding calf disbudding analgesia are required; both in terms of refining veterinarians' understanding of farmers' priorities and guiding clients on methods to improve calf welfare.

The culling of injured and non-viable pigs (Sus scrofa) (neonate to breeding stock) is a routine and necessary procedure on most farms. Usually, pigs are culled using one of the following methods: blunt-force trauma (manual and mechanical), captive-bolt stunners, electrical stunning and electrocution or carbon dioxide. Manual blunt-force trauma is one of the most widely used methods due to its low or absent operational and investment costs. However, as a method, it has serious limitations, which include the risk of incomplete concussion, pain, and distress. Manual blunt-force trauma is also aesthetically unpleasant to operators and wider society. To address these issues there has been significant recent research into the development of alternatives to manual blunt-force trauma, these include: captive-bolt stunners, on-farm, gas-based controlled atmosphere systems, low atmospheric pressure systems and electrical stunning. Some of these are currently in commercial use while others are still in the developmental phase. This review brings together the relevant research in this field, evaluating the methods in terms of mechanism of action (mechanical and physiological), effectiveness and animal welfare.

Recent developments related to quantitative analysis of the electroencephalogram (EEG) have allowed the experience of pain to be assessed more directly than has hitherto been possible. Variables derived from the EEG of animals anaesthetised using our minimal anaesthesia model respond to noxious stimulation in a manner similar to those from conscious animals. This methodology has been used in a variety of applications including the evaluation of analgesic options for painful husbandry procedures and investigation of developmental aspects of the perception of pain. We have now applied the minimal anaesthesia model to the question of the slaughter of calves by ventral-neck incision. A series of studies evaluated the magnitude of EEG response to the noxious stimulus of ventral-neck incision and the physiological mechanisms that underlie this response. We also investigated the EEG effects of stunning by non-penetrating captive bolt and the ability of such stunning to ameliorate the response to ventral-neck incision. The results demonstrate clearly, for the first time, that the act of slaughter by ventral-neck incision is associated with noxious stimulation that would be expected to be painful in the period between the incision and subsequent loss of consciousness. These data provide further support for the value of stunning in preventing pain and distress in animals subjected to this procedure. We discuss the development of the minimal anaesthesia model and its adaptation for use in the investigation of slaughter by ventral-neck incision as well as considering the contributions of these studies to the ongoing development of international policy concerning the slaughter of animals.

This paper summarises the findings from five studies in eight countries on over 1,500 cattle slaughtered commercially by the halal or shechita methods without stunning. It reports the number of cuts applied to the neck, the cutting methods and the frequency of complications during the bleeding period. Complications during the bleeding period that occurred in some cattle included: (i) delay in the time to collapse, which was interpreted as late loss of consciousness; (ii) premature arrest of bleeding from the carotid arteries due to false aneurysm formation; and (iii) blood entering the respiratory tract during bleeding. These features are important as they determine or reflect the duration of consciousness following the cut and the potential for protracted suffering from wound nociception or blood irritating the respiratory tract. When cattle were not restrained following the halal cut, they took on average 20 s to collapse. Fourteen percent stood up again after an initial collapse, and 1.5% took more than 4 min before their final collapse. Eight percent took 60 s or longer to collapse, and those animals were more likely to have false aneurysms in the severed ends of the carotid arteries. False aneurysms, which were at least 3 cm in diameter, formed in the severed cardiac ends of the carotid arteries in 10% of cattle slaughtered by halal or shechita. Some false aneurysms formed in the severed ends of the carotid arteries within 7 s of the halal cut, and in 10% of the cattle bloodflow came to a halt in one of the arteries within 10 s. On average, the false aneurysms developed within 21 s. Nineteen percent of cattle slaughtered by shechita and 58% of cattle slaughtered by halal had blood lining the mucosa of the trachea. All animals had blood lining the glottis. In both situations there could be a sense of respiratory tract irritation from the blood. It is proposed that severing the carotids at the position in the neck which corresponds to C1 will reduce the frequency of false aneurysm formation and subsequent arrested bloodflow from the severed arteries, and it will deafferent the respiratory tract reducing the transmission of potentially unpleasant sensory signals associated with blood contaminating the upper and lower parts of the tract. Most cattle subjected to halal and shechita have the neck cut at a position which corresponds to C2 to C4, and changing to a cut at C1 could partly reduce the potential for suffering during slaughter without stunning.

The current study aims to make welfare-based recommendations for gun/cartridge combinations and shooting positions that will ensure death of the sheep (horned, unhorned, rams and ewes), without the need for either sticking or pithing. The study examined the pathophysiology of captive-bolt gun (CBG) injuries that result in incomplete concussion leading to death. Behavioural, brainstem and cranial/spinal responses were examined along with gross pathology in 489 animals (116 polled ewes, 134 horned ewes, 117 polled rams and 122 horned rams) following a variety of CBG-cartridge combinations. Shooting horned rams was more challenging than unhorned sheep, partly because minor movements of the head at the time of shooting can result in deflection of the gun by the horns. Marksmanship was the definitive factor: 100% of animals that showed signs of incomplete concussion were found to have been shot incorrectly. The findings will have application when it is necessary to kill sheep on farms for disease control or euthanasia purposes.

In a series of experiments the welfare of para-aminovalerophenone (PAVP) sub-lethally poisoned rats (Rattus norvegicus) was assessed. The experiments: (i) examined the acute methaemoglobin (MetHb) profile over time; (ii) refined the LD50 estimate for PAVP in adult female rats; (iii) developed and validated three neurological tests; and (iv) assessed rats for neurological deficit following prolonged methaemoglobinaemia. The results from the first three experiments were used to refine the sub-lethal study. In the sub-lethal experiment 20 rats were gavaged with a single dose of 40 mg kg−1 PAVP (based on an LD50 estimate of 43.3 mg kg−1). Control rats (n = 10) were treated with the carrier only. Eleven (surviving) PAVP-treated rats and controls were assessed over a two-week period. Rats were tested for forelimb grip strength, stability on an inclined plane and the ability to remove tape wrapped around a forepaw in order to determine deficits in motor functions and sensorimotor integration. Signs of recovery began 3-6 h post-dosing, with all animals showing no outward signs of poisoning within 48 h, and over the 14-day post-treatment monitoring period they gained weight and increased their food consumption. There was no significant overall difference in performance between PAVP-treated and control rats in any of the three neurological tests. In the inclined plane test, performance of sub-lethally PAVP-poisoned rats appeared to be temporarily impaired with treated animals slipping at a lower angle than controls on day two. During the tape removal test, four PAVP-treated rats failed to remove the tape within the 3-min time limit on one occasion each (4/77 occasions) up to seven days post-dosing. The severity and duration of signs following acute sub-lethal PAVP poisoning appeared to be lower than those reported for existing rodenticides. It is likely that the results presented in this study extend to other MetHb-inducers.