In the expanding salmon industry, many farmers use production methods that could result in poor welfare of the fish at various points of their lifecycle. We have reviewed methods used for producing salmon for food with the aim of identifying and drawing attention to factors likely to affect farmed Atlantic salmon (Salmo salar) welfare. In addition to water conditions and high stocking density at sea, other issues are important for fish welfare. Handling and transport of salmon between fresh- and seawater phases and before slaughter can have severe negative effects and research should continue to seek improved methods. Stocking densities in fresh- or seawater have substantial effects on the welfare of salmon and a reduction in densities should be considered in order to reduce fin damage in particular. Currently used feeding systems result in starvation for some fish and fin damage for others, hence new systems should be developed. Some on-demand feeding systems improve welfare. All farmed fish should be stunned prior to slaughter, not left to die of asphyxia. Carbon dioxide and electrical stunning methods do not always stun salmon humanely. The widely used methods of percussive stunning, manual or automatic, must be precise to effectively stun large numbers of fish. Welfare outcome indicators, such as fin damage, morbidity and mortality rate, should be used in standards and laws relating to salmon welfare.

Small laboratory animals are commonly euthanased via intraperitoneal (IP) injection of sodium pentobarbital. However, there is concern that animals may experience pain prior to loss of consciousness with this delivery route. The present study investigated electroencephalographic (EEG) nociceptive responses of anaesthetised pigs to IP sodium pentobarbital injection using an established minimal anaesthesia model. Thirty commercial white line entire male pigs aged 10-15 days were minimally anaesthetised with halothane in oxygen. Following 10 min of baseline EEG data collection, pigs had their tails docked using side-cutters and, after a further 5-min interval, were euthanased via IP injection of sodium pentobarbital (250 mg kg-1). The summary variables median frequency (F50), 95% spectral edge frequency (F95) and total power (PTOT) were derived from the EEG data. For each variable in each pig, means were calculated for the following 60-s periods: immediately prior to tail-docking (baseline 1); immediately prior to pentobarbital injection (at least 4 min after docking; baseline 2); and for two consecutive 60-s periods immediately following pentobarbital injection (P1 and P2). Statistical analyses revealed no differences between the two baseline periods, indicating that transient EEG changes induced by tail-docking had resolved prior to pentobarbital injection. IP pentobarbital injection induced a significant increase in F50 and decrease in PTOT of the EEG during P1. This response is characteristic of acute nociception, indicating that conscious pigs likely perceive IP sodium pentobarbital as painful in the period prior to loss of consciousness.

Exposure to high concentrations of CO2 is a common means of stunning and killing laboratory rodents. However, there is concern regarding the potential for animals to have aversive experiences, such as pain or breathlessness, prior to loss of awareness. This preliminary study evaluated the electroencephalographic (EEG) responses of rats (Rattus norvegicus) to CO2 inhalation, using a method based on a minimal anaesthesia model previously used to assess nociception in mammals. Fifteen adult female Sprague-Dawley rats were anaesthetised with halothane in oxygen and maintained at a minimal plane of anaesthesia. EEG was continuously recorded throughout a 10-min baseline period followed by sequential exposure to 5, 15, 30 and 50% CO2. The EEG summary variables median frequency (F50), 95% spectral edge frequency (F95) and total power (PTOT) were derived from the raw EEG. The F50 of the EEG, a sensitive indicator of nociception, increased significantly above baseline during exposure to 15% CO2, suggesting this concentration was noxious to rats. This is consistent with behavioural aversion in rats at around the same CO2 concentration. Stimulation of the rat mucosal nociceptors only occurs at CO2 concentrations of 37% or greater; therefore, it is hypothesised that the observed response was a result of what would have been CO2-induced aversive respiratory sensation in conscious animals, rather than pain. This study provides some evidence that an anaesthesia model may be utilised to study the nocuous effects of low-moderate CO2 exposure in rodents.

Humane euthanasia of cattle under field conditions presents special challenges for veterinarians and producers. The purpose of this study was to evaluate the effectiveness of the CASH Dispatch Kit captive-bolt system combined with improved shot placement landmarks as a single-step euthanasia method for cattle. Cattle destined for euthanasia for reasons unrelated to the study were utilised. Adult (> 2 years), young (6-24 months) and neonatal (< 1 month) cattle each received a single shot from the CASH penetrating captive-bolt pistol. An additional group of neonatal animals was shot with a non-penetrating muzzle attachment. The shot was placed on midline halfway between the top of the poll and an imaginary line connecting the lateral canthus of each eye. Following the shot, the animals were immediately assessed for loss of consciousness based upon: i) immediate collapse (if standing); ii) loss of eye reflexes with a centered, dilated pupil; iii) lack of co-ordinated respiration; iv) lack of vocalisation; and v) lack of a righting reflex. Lack of consciousness and heartbeat were assessed at 1-min intervals until cardiac arrest. All animals were adequately stunned by a single shot. Euthanasia via a single shot was successful in 28/31, 17/19, 8/10, and 9/10 adult, young, neonate (penetrating) and neonate (non-penetrating) animals, respectively. Reasons for failure included return of co-ordinated respiration and prolonged time until cardiac arrest. A single shot from the CASH Dispatch captive-bolt system will humanely euthanase most animals. However, the results of this study indicate that application of a follow-up step to ensure death is still needed in certain instances.

Concerns over elephant welfare in UK zoos have implications for their future in captivity. To monitor improvements made to elephant welfare in UK zoos, non-invasive, valid and reliable indicators of welfare are needed. Using a rapid review strategy and critical appraisal tool, we aimed to appraise evidence from peer-reviewed literature on potential welfare indicators for captive elephants. Scopus, Web of Knowledge and Ovid were searched in January 2014 using terms relevant to captive elephants and welfare assessment. Inclusion and exclusion criteria were applied and remaining articles were critically appraised against a specially designed welfare indicator appraisal tool. Thirty-seven unique indicators of welfare were extracted from 30 peer-reviewed papers which met the inclusion criteria. Behavioural measures of welfare (n = 21) were more common than either physical (n = 11) or physiological (n = 5) measures. Stereotypies were the most frequently used behavioural measure, glucocorticoids were the most frequently used physiological measure and body condition scores were the most frequently used physical measure. There was most support for the following indicators of improved welfare state: reduced stereotypies, reduced glucocorticoids and improved body condition scores. Additional measures which require further validation but had strong associations with the most supported measures, and thus have potential use in welfare assessment, were: increased lying rest and positive social interactions. Further validation of the described measures is needed, but this information forms a crucial part of the knowledge required to efficiently monitor and improve the welfare of elephants in captivity.

Undesirable behaviours (UBs) are common in dogs and can jeopardise animal and human health, leading to dog abandonment and euthanasia. Dogs exhibiting UBs may have compromised welfare from underlying emotional motivations for the behaviour (eg anxiety) or from the methods used by owners to resolve the problem (eg aversive techniques). The objective of this study was to estimate proportional mortality due to UBs and risk factors for death due to UBs, including death from road traffic accidents, in dogs under three years of age attending primary-care veterinary practices in England from 2009-2014. Cases were identified by searching de-identified electronic patient records from primary-care veterinary practices participating in the VetCompass Programme. The findings highlight that dogs under three years of age are at a proportionately high risk of death due to UBs (33.7%) compared with other specific causes of death (eg gastrointestinal issues: 14.5%). Male dogs had 1.40x the odds of death from UB compared with females. The proportional mortality from UB for male dogs where information on the cause of death was available was 0.41. Neutered dogs had 1.94x the odds of death due to a UB compared with entire dogs. Aggression was the most prevalent UB overall. Veterinarians had recommended referral in 10.3% of cases where dogs died due to exhibiting a UB and had dispensed nutraceutical, pheromone or pharmacological treatment to 3.0% of the UB cases that died. This study shows that undesirable behaviours require better preventive measures and treatment, through further research and education of veterinarians, other professionals within the dog industry and owners.

This study aimed to refine bird-soiling as a broiler chicken (Gallus gallus domesticus) welfare indicator, and to develop and test two additional indicators, namely contact dermatitis on the breast and abdominal areas and carcase scratches. We constructed a questionnaire with pictures of birds presenting different indicator levels for classification as absent, low, moderate or severe. The questionnaire was sent to 146 invited experts for the first round and 88 for the second, in a Delphi process. Visual scales were built for the target indicators, which were tested by three assessors in ten flocks on-farm (n = 1,303 birds) and at the slaughterhouse (n = 1,631 birds). High concordance was observed among groups of Delphi respondents and among assessors. A total of 90.7% of the birds were either moderately or severely soiled, 99.9% were poorly feathered, 73.4 and 90.0% presented erythaema and carcase scratches, respectively. The correlations between litter quality and all outcomes assessed on-farm, and between bird-soiling and contact dermatitis on the breast and abdominal areas, were moderate. Results suggest that adoption of the proposed scales may improve our ability to assess broiler chicken welfare, since relevant problems were prevalent and measurement consistency acceptable. Substantial concordance observed among assessors encourages application of these animal-based indicators to assess broiler chicken welfare in a wide range of poultry houses, in a variety of different countries, thereby allowing the scales to be tested in a host of animal welfare conditions.

The housing condition of pig (Sus scrofa) fattening farms are increasingly receiving criticism, because they are associated with impaired animal welfare. Consumers view the increase in farm sizes critically, even though scientifically based knowledge on the relationship between farm size and welfare is still limited. Therefore, the aim of this study was to assess the welfare level of conventional fattening pig farms in Germany and to evaluate the relationship between farm size and animal welfare level. In total, the Welfare Quality® protocol (WQ) for pigs was applied on 60 farms. Farms were classified according to their size into small (< 1,500 pigs per farm), medium (1,500-3,000 pigs per farm) and large (> 3,000 pigs per farm). Independent of the farm size, the overall WQ classifications ‘excellent’ and ‘not classified’ were not recorded in any of the farms, while ‘enhanced’ and ‘acceptable’ was achieved by 80 and 20% of the farms, respectively. Farm sizes had no effect on any of the four principles ‘good feeding’, ‘good housing’, ‘good health’ or ‘appropriate behaviour’. Overall, moderate bursitis (35%) was found to be the most prevalent indicator of welfare-related problems. However, it did not differ between farm sizes. Another highly prevalent indicator, moderately soiled body, increased from 11.1% in small-to 20.8% in large-sized farms. In conclusion, our findings show that none of the farm sizes were superior in terms of animal welfare. Overall, acceptable or enhanced scores were achieved for many of the criteria, however the need for improvement in other criteria such as ‘expression of other behaviour’ and ‘positive emotional state’, was clear.