Isoflurane-anaesthesia used for piglet-castration: a bacteriological assessment of the anaesthetic device.

Castration of piglets with the use of isoflurane-anaesthesia in combination with an analgesic has been proven to be a welfare-friendly approach. However, castration is performed with an equipped anaesthetic device which is not profitable for small farms. Thus, this study aimed at investigating whether sharing the anaesthetic device among farms results in an elevated risk of bacteriological contamination and further spreading in spite of a thorough disinfection. The study included two groups of organic farms. Piglets (n = 1579) were anaesthetised with isoflurane supplied from an equipped device and castrated. Stationary anaesthetic devices were used in the first group of farms, whereas farms in the second group shared one device. Each farm was visited four times and the colony forming units (CFU) of total mesophilic bacteria, Staphylococcus spp., Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli were determined. Sampling took place before castration and after disinfection, and included snout masks, retaining fixtures, pedals and wheels of the device (n = 376). The results indicated presence of Staphylococcus species in 56.5% and 40.3% of samples obtained from farms using stationary and shared devices, respectively. MRSA was detected in 2.4% of the samples and only one pathogenic Shiga toxin-producing E. coli (Stx2e, F18) could be detected. Bacterial counts were lower on the shared device than on the stationary devices (p = 0.038), particularly on restraining fixtures (p < 0.05). In both groups wheels were the most and pedals the least contaminated materials (p < 0.05). It is concluded that sharing an anaesthetic device on several farms does not increase bacteriological contamination after a thorough disinfection and thus imposing no additional hygiene risk to farms with similar hygienic conditions.

Experimental Actinobacillus pleuropneumoniae challenge in swine: comparison of computed tomographic and radiographic findings during disease.

BACKGROUND: In pigs, diseases of the respiratory tract like pleuropneumonia due to Actinobacillus pleuropneumoniae (App) infection have led to high economic losses for decades. Further research on disease pathogenesis, pathogen-host-interactions and new prophylactic and therapeutic approaches are needed. In most studies, a large number of experimental animals are required to assess lung alterations at different stages of the disease. In order to reduce the required number of animals but nevertheless gather information on the nature and extent of lung alterations in living pigs, a computed tomographic scoring system for quantifying gross pathological findings was developed. In this study, five healthy pigs served as control animals while 24 pigs were infected with App, the causative agent of pleuropneumonia in pigs, in an established model for respiratory tract disease. RESULTS: Computed tomographic (CT) findings during the course of App challenge were verified by radiological imaging, clinical, serological, gross pathology and histological examinations. Findings from clinical examinations and both CT and radiological imaging, were recorded on day 7 and day 21 after challenge. Clinical signs after experimental App challenge were indicative of acute to chronic disease. Lung CT findings of infected pigs comprised ground-glass opacities and consolidation. On day 7 and 21 the clinical scores significantly correlated with the scores of both imaging techniques. At day 21, significant correlations were found between clinical scores, CT scores and lung lesion scores. In 19 out of 22 challenged pigs the determined disease grades (not affected, slightly affected, moderately affected, severely affected) from CT and gross pathological examination were in accordance. Disease classification by radiography and gross pathology agreed in 11 out of 24 pigs. CONCLUSIONS: High-resolution, high-contrast CT examination with no overlapping of organs is superior to radiography in the assessment of pneumonic lung lesions after App challenge. The new CT scoring system allows for quantification of gross pathological lung alterations in living pigs. However, computed tomographic findings are not informative of the etiology of respiratory disease.