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Copyright of Canadian Veterinary Journal / Revue Vétérinaire Canadienne is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Negative emotional states, or negative affect, resulting from concussion is of increasing concern in both civilian and military populations. Evidence of repeated concussion resulting in depression and anxiety is mounting. Studies currently used to test negative affect following concussion in animals, such as the elevated plus maze and Morris water maze, have yielded conflicting results. In the current study, we developed a model to investigate negative affect following multiple concussions induced by the projectile concussive injury (PCI) model. 22 kHz ultrasonic vocalizations are associated with negative affective stimuli in rats. Forty-eight hours post-injury, negative affect was examined using the air-puff induced negative vocalization test. Animals were placed into a clean acrylic box. A 5min baseline recording was followed by 15 air puffs (55 psi) spaced 30 sec apart aimed at the upper back and neck. Recording continued until vocalization was terminated for 1min. Total 22 kHz vocalizations, duration of vocalization, and threshold (number of puffs needed to elicit response) were significantly different between injured animals and shams (p < 0.05). Injured animals produced on average 153.5 - 55.13 more vocalizations. Additionally, injured animals vocalized to fewer air-puffs, exhibiting a 1.5 fold lower threshold for the expression of negative affect. They also vocalized on average 4 min longer than shams, demonstrating that the same stimulus induced a more negative state in injured animals. Negative vocalizations are an indication of general negative affect and do not alone denote a specific type of negative state (e.g. sadness, anxiety, fear). However, it is likely that injured animals in the current study show greater fear and anxiety and perhaps have a lower threshold for negative environmental stimuli. Further studies are underway to examine these possibilities. Here we show that the air-puff vocalization test is an innovative, non-invasive, straightforward approach to assessing negative affect resulting from mild brain injury that can be utilized to evaluate novel therapies for the treatment of negative affect following concussive injury. [ABSTRACT FROM AUTHOR]

Infectious enterocolitis is a significant cause of mortality in meat rabbits. Disease risk is enhanced by intensive rearing practices and poor on-farm biosecurity. This investigation was undertaken in farmed meat rabbits during an Ontario-wide outbreak of enteritis with high mortality to determine the prevalence of causative agents. A survey evaluating on-farm biosecurity practices was also conducted to identify potential means of pathogen contamination and zoonotic risks. Gross and microscopic pathology evaluations combined with microbiologic testing were conducted on 95 rabbits over spring and winter months. Escherichia coli and Clostridium spiroforme were most commonly associated with enteritis in rabbits regardless of age or season and lesions were significantly more severe in mature does ( P < 0.0001). The survey results demonstrated a lack of consistent on-farm biosecurity practices. The infectious nature of enteric disease of rabbits combined with poor biosecurity practices may contribute to disease transmission within and between farms.