Adrenocortical suppression in the dog given a single intramuscular dose of prednisone or triamcinolone acetonide

Adrenocortical function was assessed in dogs given a single intramuscular dose of either prednisone or triamcinolone acetonide (TCA; or saline solution to controls) to determine the duration of adrenocortical suppression caused by 2 commonly used glucocorticoids. The glucocorticoids were administered at recommended therapeutic doses; therefore, dogs given prednisone received a greater amount of glucocorticoid activity than did in dogs given TCA. Basal and ACTH-stimulated plasma cortisol concentrations, as determined by radioimmunoassay, were obtained once a week. Total intravascular eosinophil concentration and skin responses to intradermally injected histamine phosphate were quantitated. Dogs given TCA showed suppressed basal and ACTH-stimulated plasma cortisol concentrations 1 week after injection; the latter change persisted 2 weeks after injection. Adrenocortical function in 1 of 4 dogs given TCA remained suppressed for 4 weeks. In contrast, prednisone did not significantly alter adrenocortical function. Although intravascular eosinophil concentrations did not vary among groups, skin responses to intradermally injected histamine phosphate were reduced 6 days after prednisone and TCA were given.     

New method for estimating the volume and volume fractions of the nasal structures in the goose (Anser anser domesticus) using computed tomography images

1. The conchae within the nasal cavity of poultry are important for water and energy conservation, but have not been experimentally evaluated. The aim of the present study was to determine the accuracy of volume and volume fraction estimates of the conchae, nasal septum and nasal cavity.

2. The nasal cavities of 7 adult goose heads were scanned using computed tomography (CT), with images sampled randomly at a 1/5 sampling fraction. Physical sections were obtained from the same samples, using an electric saw that had an adjustable section range, and provided 14 to 15 sections with a thickness of 2.5 mm. The section surface areas of the nasal cavity, nasal septum and conchae were estimated using the Cavalieri principle. Results obtained using the CT and physical section images were compared. Volumes and volume fractions obtained from the physical sections were accepted as the gold standard and differences in the CT images were determined.

3. Multiplication of the data obtained on the CT images with the deviation percentage of the physical sections produced normalised values. No differences were observed between the gold standard data and the CT images. While it was possible to normalise the obtained data using the gold standard values, the raw data could also be used for comparative studies because the deviations from normal would be similar for all groups.

4. Our study showed that the nasal structures could be estimated in vivo using CT images.     

Risk factors for musculoskeletal injuries in 2-year-old Thoroughbred racehorses

Musculoskeletal injuries (MSI) in racehorses have been identified as the most common cause of lost training days and weeks spent resting at pasture. Several training-, track- and horse-related risk factors have been identified. However, there is no clear understanding of the inter-relationship between these factors. The aim of this longitudinal cohort study was to investigate risk factors for MSI in 2-year-old Thoroughbred racehorses. Australian Thoroughbred trainers were convenience sampled and enrolled in a 27-month longitudinal cohort study. The study population consisted of all 2-year-old Thoroughbred racehorses trained by a participating trainer. Horses were followed from the time of enrollment until the completion of the study or until they were lost to follow-up. Trainers were visited at approximately 14-day intervals to collect training and injury data. Training days were categorised as fast days if the maximum speed during training exceeded 800 m/min. For each horse, the first training period that included one or more fast days was analysed. A multiple logistic regression model was used to determine those horse- and training-related variables that were associated with MSI. Data from 274 horses trained by 14 trainers at five racetracks were analysed. Forty percent of the horses sustained a MSI during their first fast preparation. The average distance trained at speeds >or=800 m/min and the percentages of fast days from the first fast day until the end of the preparation were the only variables associated with MSI. After accounting for these variables there were still significant differences between trainers. This suggests that there are other training-related variables such as the rate of increase in distance trained at speeds >or=800 m/min that may be risk factors for MSI. In addition, other factors such as the level of veterinary involvement and the training centre/racetrack may be risk factors for MSI. More analysis using multi-level modelling is required to determine the relationship between trainer- and track-related risk factors.     

Sarcoid granuloma-like lesions in the lungs of broiler chicks.

Sarcoid granuloma-like lesions were observed in the lungs of two broiler chicks showing depressed growth. Multinucleated giant cells in the lesions often contained foreign bodies comprising amorphous and laminated material. These were morphologically similar to Schaumann bodies found in human sarcoidosis. This is the first report of sarcoid granuloma-like lesions and Schaumann body-like material in chickens.