A molecular epidemiologic investigation of Salmonella from a meat source to the feces of captive cheetah (Acinonyx jubatus).

Low cheetah (Acinonyx jubatus) birth rates were observed for a long time in a captive breeding facility in which Salmonella, which was possibly present in contaminated beef, was isolated from still-born lion (Panthera leo) cubs. Salmonella, including 14 isolates of Salmonella serovar typhimurium and 19 isolates of Salmonella serovar muenchen, was subsequently isolated 47 times from 378 meat samples at the facility during a 13-mo period. Salmonella, including 26 isolates of S. serovar typhimurium, 10 of S. serovar muenchen, and 11 other serovars, also was isolated 54 times from 119 fecal samples. Only three plasmid profiles were identified in 59 S. typhimurium isolates from both meat and fecal samples. Although random-amplified polymorphic DNA fingerprinting using different primers in the polymerase chain reaction was able to distinguish between S. typhimurium and S. muenchen and to demonstrate similar chromosomal DNA fingerprints in some of the isolates from meat and feces, the results were not consistent enough to prove that the Salmonella in the feces originated from contaminated meat. However, the predominance of only two serovars in the meat fed to carnivores and in the feces of these animals suggests that the meat was the source of the Salmonella organisms in the feces.     

Chloramphenicol 3. Clinical pharmacology of systemic use in the horse

The use of chloramphenicol in the horse is now prohibited as horses are classified as food-producing animals. However, chloramphenicol has until recently been widely available for oral, intramuscular or intravenous administration. A critical appraisal of the published literature on the use of chloramphenicol in the horse clearly demonstrates that there are sound pharmacokinetic and microbiological reasons for concluding that chloramphenicol is not an appropriate antibiotic for systemic use. The short half-life of chloramphenicol in the horse, together with the broad range of minimum inhibitory concentrations of target pathogens, preclude the use of practical dosage regimens. It can be concluded that the withdrawal of chloramphenicol will have no adverse effects on chemotherapy in the horse.     

Pharmaceutical evaluation of compounded trilostane products

Compounded trilostane capsules (15 mg, 45 mg, or 100 mg) were purchased from eight pharmacies and assayed for content and dissolution characteristics. Capsules made in-house containing either inert material or 15 mg of the licensed product and proprietary capsules (30 mg and 60 mg) served as controls. Findings were compared with regulatory specifications for the licensed product. Altogether, 96 batches of compounded trilostane and 16 control batches underwent analysis. In total, 36 of 96 (38%) compounded batches were below the acceptance criteria for content. The average percentage label claim (% LC) for each batch ranged from 39% to 152.6% (mean, 97.0%). The range of average % LC for the controls was 96.1-99.6% (mean, 97.7%). The variance in content of the purchased compounded products was substantially greater than for the controls (234.65 versus 1.27; P<0.0001). All control batches exceeded the acceptance criteria for dissolution, but 19 of 96 batches (20%) of purchased compounded products did not. Mean percent dissolution for the purchased compounded products was lower than for controls (75.96% versus 85.12%; P=0.013). These findings indicate that trilostane content of compounded capsules may vary from the prescribed strength, and dissolution characteristics may not match those of the licensed product. The use of compounded trilostane products may therefore negatively impact the management of dogs with hyperadrenocorticism.     

Genetic parameters for resistance to Haemonchus contortus in Merino sheep in South Africa

Resistance to natural infections of Haemonchus contortus (wireworm) was studied in Merino sheep. From February 1995 to July 1996 data were collected from the OTK Merino Stud on the farm Wildebeesfontein near Hendrina in Mpumalanga province. From March 1998 to January 2000 another Merino flock at Irene in Gauteng province was included in the study. In both cases, 50 randomly-chosen animals from each group of lambs weaned were sampled weekly for faecal egg count (FEC) until a mean of 2500 eggs per gram faeces (epg) was reached. At this stage, all lambs in the group were sampled for FEC, packed cell volume (PCV) and live mass in the case of the Wildebeesfontein flock. Animals were monitored from weaning to about 1 year of age. Data from 5 different groups of lambs (583 animals and 1722 records in total) with genetic links were accumulated and analysed. Variance components and resulting heritabilities for logFEC and PCV were estimated using a bivariate animal model with repeated records. The estimated heritabilities were 0.24 +/- 0.02 for logFEC and 0.14 +/- 0.02 for PCV. A strong negative correlation (-0.84 +/- 0.06) existed between the 2 traits. The genetic correlation between PCV and live mass for the Wildebeesfontein flock was low (0.28 +/- 0.09), while that between logFEC and live mass was negative, although not significantly different from zero (-0.13 +/- 0.09). These results suggest that FEC can be used as a selection criterion for resistance to H. contortus infections in Merino sheep.     

Pharmacokinetics, stability, and retrospective analysis of use of an oral gel formulation of the bovine injectable enrofloxacin in horses

In many cases of equine infectious disease, long-term administration of antimicrobial drugs is required. Oral agents are preferred because of the relative ease of administration compared with other routes. Enrofloxacin has been shown to be effective against a variety of equine pathogens, but oral administration of this drug has proved difficult in horses. An oral gel formulation made from the injectable cattle product produces blood levels sufficient to resolve infections caused by a variety of common equine pathogens.     

Pharmacokinetics of carprofen and firocoxib for medication control in racing greyhounds

Animals used in sport should be treated as required to ensure animal welfare but any such use of medication should also be controlled to ensure integrity. Pharmacokinetic studies on groups of six greyhounds were performed to measure plasma and urine levels of carprofen and firocoxib to inform medication control advice. Using the standard methodology for medication control the Irrelevant Plasma Concentration was determined as 20 and 2 ng/mL for carprofen and firocoxib, respectively. The Irrelevant Urine Concentration was also determined as 0.3 and 2 ng/mL for carprofen and firocoxib, respectively. These Irrelevant Plasma and Urine Concentrations will allow laboratory Screening Limits, Detection Times and Withdrawal Time advice to be determined and publicised by regulators of greyhound racing. The Screening Limits will also inform Recommended Limits of Detection if meat-containing residues of these medications are fed to greyhounds.     

Antagonism of detomidine with tolazoline in isoflurane-anaesthetised ponies

The effects of tolazoline (4.0 mg/kg iv) antagonism of detomidine (0.02 mg/kg iv) were evaluated in isoflurane-anaesthetised, ventilated ponies. Each of 6 ponies received both tolazoline and saline treatment during separate anaesthetic episodes only (no surgery was performed). Detomidine administration produced an increase in blood pressure, decrease in heart rate and decrease in P_aO₂ Tolazoline treatment transiently increased heart rate while blood pressure returned to baseline after both treatments. Arterial oxygenation decreased further after tolazoline treatment while oxgenation recovered towards baseline with saline treatment. No other cardiopulmonary effects were detected. Recovery from anaesthesia tended to be more rapid when detomidine was antagonized. The potential benefit of antagonizing detomidine-induced bradycardia with tolazoline, during isoflurane anaesthesia should be weighed against the potential to produce a decrease in arterial oxygenation. The mechanism for this effect is not clear.