Anaesthetic and cardiorespiratory effects of a constant rate infusion of fentanyl in isoflurane-anaesthetized sheep.

OBJECTIVE: To determine the anaesthetic and cardiorespiratory effects of a constant rate infusion of fentanyl in sheep anaesthetized with isoflurane and undergoing orthopaedic surgery. STUDY DESIGN: Prospective, randomised, 'blinded' controlled study. ANIMALS: Twenty healthy sheep (weight mean 41.1 ± SD 4.5 kg). METHODS: Sheep were sedated with intravenous (IV) dexmedetomidine (4 µg kg(-1) ) and morphine (0.2 mg kg(-1) ). Anaesthesia was induced with propofol (1 mg kg(-1)  minute(-1) to effect IV) and maintained with isoflurane in oxygen and a continuous rate infusion (CRI) of fentanyl 10 µg kg(-1)  hour(-1) (group F) or saline (group P) for 100 minutes. The anaesthetic induction dose of propofol, isoflurane expiratory fraction (Fe'iso) required for maintenance and cardiorespiratory measurements were recorded and blood gases analyzed at predetermined intervals. The quality of recovery was assessed. Results were compared between groups using t-tests or Mann-Whitney as relevant. RESULTS: The propofol induction dose was 4.7 ± 2.4 mg kg(-1) . Fe'iso was significantly lower (by 22.6%) in group F sheep than group P (p = 0). Cardiac index (mean ± SD mL kg(-1)  minute(-1) ) was significantly (p = 0.012) lower in group F (90 ± 15) than group P (102 ± 35). Other measured cardiorespiratory parameters did not differ statistically significantly between groups. Recovery times and recovery quality were statistically similar in both groups. CONCLUSIONS AND CLINICAL RELEVANCE: Fentanyl reduced isoflurane requirements without clinically affecting the cardiorespiratory stability or post-operative recovery in anaesthetized sheep undergoing orthopaedic surgery.

Hypervitaminosis D has no positive effects on goat tuberculosis and may cause chronic renal lesions.

BACKGROUND: There is evidence for a link between vitamin D deficiency and active tuberculosis (TB). In human beings, several trials have evaluated the role of vitamin D supplementation in TB treatment with conflicting results. However, the role of vitamin D supplementation in animal TB control has received less attention. The authors evaluated the benefit of vitamin D supplementation for preventing mycobacterial infection or reducing TB lesions (TBL) in a controlled trial with goats naturally exposed to Mycobacterium caprae. METHODS: Two groups of goats, a vitamin D-supplemented group and a non-supplemented control group, were housed for 10 months in direct contact with M caprae-infected adult goats. Upon contact with the infected adult goats, all animals were TB-tested every two months. RESULTS: No experimental evidence of a protective effect of vitamin D supplementation based on M caprae culture prevalence, TBL prevalence, median TBL score or the proportion of single versus multiple organs presenting TBL was observed. CONCLUSION: The results indicate that, in the conditions used in this study, vitamin D supplementation in goats does not reduce TB infection risk nor the diffusion and severity of TBL. In addition, vitamin D-supplemented goats presented hyperphosphataemia and renal injury with calcifications suggestive of vitamin D intoxication.