An investigation was performed to determine whether high concentrations of carbon dioxide (CO 2 ) at 70-98% in atmospheric air are a suitable alternative for stunning rabbits compared to conventional approaches such as electronarcosis. Aversion to the gas and efficacy in causing prolonged unconsciousness and death were studied in a total of 480 rabbits by means of behavioural parameters, physiological indicators (presence of rhythmic breathing and corneal reflex) and electroencephalography (EEG, brain function). The use of any of the 4 studied concentrations of the gas caused more nasal discomfort and vocalisations than the use of atmospheric air (P<0.001). EEG activity confirmed that loss of posture is a good indicator of the onset of unconsciousness in rabbits exposed to CO 2 , occurring earlier (P<0.05) at 90 and 98% than at 70 and 80%. Rabbits showed signs of aversion for 15 s before the onset of unconsciousness, which occurred around 30 s after the beginning of the exposure to the gas, similar to species such as swine in which high concentrations of CO 2 are also used for stunning. CO 2 at 80 to 98% is suggested as a reasonable concentration range to induce a long state of unconsciousness and death in rabbits, while 70% CO 2 is not recommended because it requires too long duration of exposure (more than 360 s) to ensure effectiveness. Despite the advantages in terms of pre-stun handling and irreversibility, CO 2 is not free of animal welfare concerns. In consequence, a debate is necessary to ascertain if CO 2 can be considered a suitable alternative to stun rabbits, considering the advantages and drawbacks cited, quantified in the present study as 15 s of aversion (nasal discomfort and vocalisations) before losing posture.
Rabbits are the third species in terms of number of animals reared for meat production in the world. However, in comparison to other species, very few studies have focused on their welfare. The aim of the present study is to implement an animal welfare-assessment protocol developed through a multidimensional approach and containing a number of animal-based measures for bucks, does, and kit rabbits. Thirty Spanish farms with conventional cages in the first year of integration in an animal welfare certification scheme were visited during 2019 and audited by the same auditor. The protocol is divided into four principles and 11 criteria. The Good Feeding principle includes eight parameters (one animal-based), Good Housing includes 15 parameters (six animal-based), Good Health includes 26 parameters (16 animal-based), and Appropriate Behavior contains nine parameters (four animal-based). In general, the main problems found were the absence of platforms, low space allowance and low height of the cage, inappropriate systems for performing emergency killing, insufficient protection of does from other adjacent does when housed individually, and absence of enrichment material. To a minor degree, but also found in an important number of farms, was a lack of temperature data records, high replacement rates of does, and lack of mortality-rate data records. However, in general, most of the farms obtained a good overall score, the maximum found being 73 out of 100 points. Nevertheless, none of the farms reached an excellent score, and four farms were scored below the 55 points required in the animal welfare certification scheme. The Good Feeding principle obtained the highest score, reaching excellent in all farms, and Appropriate Behavior the lowest one, with values ranging from 21 to 41 points out of 100. The results probably show how, for years, rabbit producers have been very focused on feeding needs and very little attention has been paid to behavioral needs.
This study assessed aversion, stunning effectiveness, and product quality of nitrogen and carbon dioxide (CO2) mixtures used for stunning pigs. A total of 1852 slaughter pigs divided into two similar batches was assessed during routine slaughter in a Swedish commercial abattoir using either hypercapnic-hypoxia (20% CO2 and less than 2% O2; 20C2O) or hypercapnia (90% CO2; 90C) gas mixtures. Behavioral indicators of aversion and discomfort were recorded. After exposure, the stunning quality was assessed through brainstem reflexes. After slaughter, the pH and electric conductivity of carcasses were assessed to estimate the incidence of pale, soft, and exudative (PSE) pork, and the presence of ecchymosis were inspected. Compared to 90C, pigs exposed to 20C2O showed a later (p < 0.05) onset of behaviors indicative of aversion, and a lower (p < 0.01) incidence of breathlessness. However, unconsciousness (i.e., losing posture) appeared earlier (p < 0.01) in 90C compared to 20C2O. In 90C, all (100%) pigs were adequately stunned, whereas in 20C2O a 7.4% of pigs showed signs of poor stunning, especially when oxygen concentrations were >2% (p < 0.001). The percentage of PSE carcasses was higher (p < 0.01) in 20C2O than 90C. In conclusion, compared to 90C, 20C2O reduced aversion and discomfort but showed lower stun effectiveness, especially when O2 was above 2%, and a slightly poorer pork quality.
The objective of the present study is to present an animal welfare assessment protocol for growing-rabbits for discussion after its implementation in 32 farms from Spain and Portugal. The protocol comprises the principles of Good Feeding, Good Housing, Good Health and Appropriate Behaviour of the Welfare Quality protocols and includes 36 welfare parameters. Overall, the protocol showed a good capacity for discrimination between farms, with scores ranging 44 to 82 points. The protocol seems reliable for the assessment of animal welfare after proper training of auditors. However, for the criteria social behaviour and other behaviours, further research is needed to ascertain if the methodology and times of observation used are appropriate. Some farms had high mortality rates with a low prevalence of health problems, while others had low mortality rates with high prevalence of health problems due to different managements of culling. The protocol should be improved, to impede farms with high mortality rates but a low prevalence of health issues the day of the audit from obtaining better scores than the second type of farms, by limiting the compensation in key measures. The main points to be solved in the growing-rabbit farms were: to provide more space to the animals; register the number of animals culled accurately; change cervical dislocation for another killing method and provide the farmers training in animal welfare.
The aim of the present study was to compare intramuscular injection with a needle and intradermic needle-free vaccinations against porcine reproductive and respiratory syndrome (PRRS) in piglets at 28 days old by studying behavioral and physiological reactions. A total of 72 piglets divided into 2 sex-balanced batches were assessed. Within each batch, the piglets were divided into three treatments, which were Hipradermic (0.2 ml of UNISTRAIN® PRRS vaccine administered with an intradermic needle-free device), Intramuscular (IM, 2.0 ml of vaccine), and Control (not vaccinated). Before the vaccination, the piglets were trained to cross a 4-m-long raceway to perform an aversion learning test. The day of vaccination, the time taken to cross the raceway was registered for each piglet at different times: prior to the vaccination and 10 min, 2, 24, 48, and 72 h after the vaccination, to measure variations in these times as signs of aversion to the vaccination process. Vocalizations, as potential signs of pain, were recorded as well at the end of this raceway to analyze their frequency (Hz), duration, and level of pressure (dB) at the moment of vaccination. Salivary cortisol, as a sign of the HPA-axis activity, was assessed 10 min after the vaccination. In addition, activity budgets, local reaction to the vaccine, and serological titer were also considered in the study. Ten minutes after the vaccination, the IM piglets took longer (p < 0.001) to cross the raceway than did the Hipradermic and Control piglets. Vocalizations were significantly different between the three treatments: the Control piglets produced vocalizations with the lowest frequency (p < 0.001) and level of pressure (p < 0.001), and IM with the highest, with Hipradermic in a significant intermediate position (p < 0.001). Accordingly, the day of the vaccination, IM and Hipradermic animals were lying on the side of the vaccine administration a greater proportion of time than were the Control piglets (10, 11, and 6%, respectively; p = 0.027). Salivary cortisol was not significantly different between treatments. The serum titer of antibodies against the PRRS was higher (p < 0.001) in both vaccinated treatments in comparison to the Control piglets. It is concluded that the Hipradermic needle-free vaccination may result in a less aversive experience in piglets than did intramuscular vaccination.
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