Lucía Améndola

We evaluated the convergence between the facial vein and the submental/labialis-inferior as an alternative site to the facial vein in the submental region for blood collection in mice. Three groups of CD1 female mice ( n = 10 mice/group) were used for three blood collection occasions from the convergence site. A fourth blood collection was performed from the convergence site for one group and the facial vein for the other two. Total blood removed, collection success rate, and clinical signs were evaluated. Total blood removed, and collection success rate was stable across collection occasions at the convergence site. When compared with the facial vein, the convergence site showed milder tissue damage, a higher collection success rate and a larger amount of total blood removed. Results indicate that the convergence site is more effective than the facial vein site for bleeding mice, but has an increased risk of overcollection, thus is recommended for a target volume of less than 10% of circulating blood volume.

Case studies can be valuable tools in veterinary curricula to help students develop critical thinking skills. Little research has investigated how cases can affect student attitudes on complex animal welfare issues. The objectives were to determine if a role-play case on piglet castration would affect veterinary students’ (a) ability and confidence in recalling scientific concepts regarding identification and management of pain in animals; (b) attitudes toward pigs, animal pain, and pain management; and (c) self-reflection on different viewpoints on pain and pain management in animals. First-year veterinary students enrolled in a core animal welfare course participated in a 4-week piglet castration case that included group assignments and role-playing. Students completed pre- and post-case quizzes and surveys ( n = 128), as well as a written reflection after the case ( n = 133). The effects of the case were assessed using quantitative (paired t-tests and Cochran's Q tests for quiz and survey responses) and qualitative (thematic analysis of written reflections) analyses. Students scored 8.6% higher on their post-case quiz and had slightly more positive attitudes toward pigs and the practicality of providing pain management for pigs after the case. Qualitative analysis of the written reflections revealed four main themes, including student preconceptions about pain in animals, flexibility or resistance to change their views on pain management, challenges associated with navigating different perspectives, and key takeaways from the case. Results indicate that role-play cases may help veterinary students learn about, and reflect on, complex animal welfare issues such as pain management.

Within veterinary education, case studies promote critical thinking and provide an opportunity for students to solve problems they may encounter after graduation. Cases are useful for many disciplines within veterinary medicine, but are particularly beneficial for teaching complex, multidisciplinary topics such as animal welfare. There are several resources within the literature describing methods for creating effective cases for a wide variety of educational disciplines. However, animal welfare educators are not often provided guidance on how to develop their own cases and seldom get the opportunity to receive feedback on cases they have created. The goal of this article is to provide animal welfare educators with a resource they can use when creating their own case studies for veterinary students. Our specific objective is to describe the process used to develop and evaluate farm animal welfare case studies for veterinary students.

Here we document how rats separate their living space into different functional regions. Five groups of four female Sprague Dawley rats were housed in caging systems that consisted of two standard cages connected by a tube. Both cages were provided with the same amount of bedding and nesting materials, but only one contained food and water. Nesting cover and weight of each cage were measured once a week for five weeks during cage cleaning. We found that the cages with food and water had 9% less nesting material coverage but had gained 90% more weight when compared with cages where food and water were absent. These results indicate that, when provided with separate spaces, rats move nesting materials away from the cage containing food and water sources, but preferentially excrete in the cage with water and food.

Laboratory mice are commonly euthanised with carbon dioxide (CO₂); however, there is ample evidence that this gas is aversive. Previous work suggests that sedation achieved via injection with benzodiazepines prior to CO₂ administration could reduce aversive behaviours during euthanasia. We explored the potential of using a voluntarily ingested sedative (tiletamine-zolazepam, Zoletil^®) prior to euthanasia. Male and female C57BL/6 mice were allocated into one of the five experimental groups, which differed in the dose of Zoletil: 0, 10, 20, 40, 80 or 100 mg/kg. A dose of 20 mg/kg was found to achieve mild sedation prior to euthanasia; mice which received this dose numerically reared and walked on the cage lid less, and showed ataxia, immobility and recumbency for longer than mice that received a lower dose. During euthanasia, mice that received 20 mg/kg showed fewer aversive responses to CO₂. Doses of 40 to 100 mg/kg were associated with signs of moderate to severe sedation, but resulted in an incomplete intake of the sedative, which made the interpretation of the aversiveness to CO₂ difficult. Voluntary oral administration of a sedative is an effective, affordable, and easy way to minimize the stress of mice to euthanasia with CO₂.

Evidence indicates that carbon dioxide (CO₂) induces negative affective states (including anxiety, fear and distress) in laboratory rodents, but many countries still accept it for euthanasia. Alternative methods (e.g. inhalant anaesthetic) may represent a refinement over CO₂ but are not widely adopted. We conducted an online survey of Canadian and European laboratory animal professionals and researchers ( n = 592) to assess their attitudes towards the use of CO₂ and alternative methods for rodent euthanasia using quantitative 7-point scale (from 1 (= strongly oppose) to 7 (= strongly favour) and qualitative (open-ended text) responses. CO₂ was identified as the most common method used to kill rodents, and attitudes towards this method were variable and on average ambivalent (mean ± SD score on our 7-point scale was 4.4 ± 1.46). Qualitative analysis revealed four themes relating to participant attitude: (a) the animal’s experience during gas exposure; (b) practical considerations for humans; (c) compromise between the animal’s experience and practical considerations; and (d) technical description of the procedure or policies. Many participants (51%) felt that there were alternatives available that could be considered an improvement over CO₂, but perceived barriers to implementing these refinements. Qualitative analysis of these responses revealed five themes: (a) financial constraints; (b) institutional culture; (c) regulatory constraints; (d) research constraints; and (e) safety concerns. In conclusion, concerns regarding the use of CO₂ often focused on the animal’s experience, but barriers to alternatives related to operational limitations. New research is now required on to how best to overcome these barriers.

Feelings of fear, anxiety, dyspnea and panic when inhaling carbon dioxide (CO₂) are variable among humans, in part due to differences in CO₂sensitivity. Rat aversion to CO₂consistently varies between individuals; this variation in aversion may reflect CO₂sensitivity, but other personality traits could also account for individual differences in aversion. The aims of this study were to 1) assess the stability of individual differences in rat aversion to CO₂, 2) determine if individual differences in sweet reward motivation are associated with variation in aversion to CO₂, and 3) assess whether variation in aversion to CO₂is related to individual differences in motivation to approach gains (promotion focus) or maintain safety (prevention focus). Twelve female Sprague Dawley rats were exposed multiple times at three different ages (3, 9 and 16 months old) to CO₂in approach-avoidance testing to assess motivation to avoid CO₂against motivation to gain sweet rewards. Rats were also tested for motivation to find hidden sweet rewards, and for their motivation to approach rewards or darkness. Tolerance to CO₂increased with repeated exposures and was higher at older ages. Individual differences in aversion to CO₂were highly repeatable but unrelated to motivation for sweet rewards or the strength of promotion and prevention focus. These results indicate that individual differences in aversion to CO₂reflect variation in CO₂sensitivity.

Carbon dioxide (CO₂) gradual-fill is commonly used to kill laboratory rats, but this use remains controversial due to a lack of agreement between studies. Inconsistencies may arise from differences in behaviors measured (e.g. active versus passive behaviors), in how rats cope with threats, or in rat sensitivity to CO₂. The aims of the current study were to 1) describe active and passive responses during CO₂ forced exposure, 2) determine if these responses are consistent within individuals and across aversive stimuli, 3) assess individual differences in aversion to CO₂ in aversion-avoidance and approach-avoidance tests and 4) determine how responses in aversion tests relate to individual differences in behavior during forced exposure. Twelve Sprague Dawley female rats were exposed twice to three treatments: CO₂, oxygen (O₂), and fox scent, and were exposed to CO₂ twice in each aversion test. The change in behavior from baseline was higher for rearing and locomotion when rats were exposed to CO₂ than when exposed to O₂ and fox scent. Responses varied among rats but were consistent across multiple tests within rats. For example, rearing was consistent within individuals between two exposures to CO₂. Similarly, the strength of aversion was consistent within individuals across multiple exposures to CO₂ in aversion-avoidance and approach-avoidance testing. Latency to avoid CO₂ in aversion-avoidance tests was negatively correlated with rearing during CO₂ forced exposure. Collectively, these results indicate that rat responses to CO₂ vary between (but are consistent within) individuals, suggesting that rats vary in CO₂ sensitivity. However, even the less responsive rats avoided CO₂ concentrations far below those necessary to achieve unconsciousness, indicating that all rats likely experience negative states when euthanized with CO₂.