The seroprevalence of Toxoplasma gondii antibodies in a sample of 292 merino sheep farmed in a semi-intensive manner in the Overberg region of the Western Cape, South Africa, was investigated. Antibody seroprevalence was determined by enzyme-linked immunosorbent assay. Of the total sample, 23 sheep tested positive for T. gondii antibodies (8%; 95% CI: 4.7688-10.9846). There was no statistically significant relationship between seroprevalence and age of the sheep. The highest seroprevalence was found in sheep between 28 and 40 months old; a total of 19 sheep were seropositive by 40 months. No seropositive sheep were found in the age group between 16 and 28 months. The seroprevalence reported in this study is higher than what has previously been reported for the Western Cape (6%) and across South Africa on average (4.7%). As sheep farming is economically significant in South Africa, the presence of T. gondii amongst sheep may pose a production threat to the small-stock industry as well as to public health and food security. We therefore recommend further surveillance to identify high-risk animal populations so that local control measures can be put in place.

OBJECTIVE To characterize and compare gait variables in Doberman Pinschers with and without cervical spondylomyelopathy (CSM). ANIMALS 18 Doberman Pinschers (9 clinically normal dogs and 9 CSM-affected dogs). PROCEDURES A neurologic examination was performed on all dogs. The diagnosis of CSM was confirmed with MRI. Temporospatial and kinetic gait variables were measured by use of a pressure-sensitive walkway. Temporospatial variables evaluated included stance phase duration, swing phase duration, gait cycle duration, stride length, and gait velocity. Kinetic variables evaluated included peak vertical force and vertical impulse. Random-effects linear regression was used to determine the difference between CSM-affected and clinically normal dogs for each of the 7 variables. RESULTS Values for temporospatial variables were significantly smaller in the thoracic limbs of CSM-affected dogs, compared with values for the thoracic limbs of clinically normal dogs. For the kinetic variables, peak vertical force was significantly higher in the thoracic limbs than the pelvic limbs for all dogs. Vertical impulse values were higher in the thoracic limbs than the pelvic limbs. There were significant differences in mean vertical impulse between the thoracic and pelvic limbs for both groups. CONCLUSIONS AND CLINICAL RELEVANCE In this study, significant differences in temporospatial variables were identified between the thoracic limbs of clinically normal and CSM-affected dogs, with the values being smaller for the CSM-affected dogs than for the clinically normal dogs. A pressure-sensitive walkway may provide a valid, practical option for rapid, objective assessment of gait and response to treatment in dogs with CSM.

OBJECTIVE To compare effects of training on conventional and underwater treadmills on fiber properties and metabolic responses of the superficial digital flexor (SDF) and gluteal muscles to high-speed exercise in horses. SAMPLE 6 unconditioned Quarter Horse–type horses. PROCEDURES 6 horses were walked on underwater and conventional treadmills for 5 d/wk (maximum, 40 min/d) for 8 weeks in a randomized crossover design (60-day detraining period). Horses underwent a standardized exercise test (SET) at high speed before and after training. Analyte concentrations and fiber characteristics were measured in muscle biopsy specimens obtained from horses before and after each SET. RESULTS Lactate concentration increased 2- to 3-fold in SDF and gluteal muscle after SETs. No training effect was identified on muscle fiber type composition, type II fiber diameter, muscle analyte concentrations, blood lactate concentration, or heart rate responses. Maximum diameters of type I fibers decreased significantly in gluteal muscle with conventional treadmill training and decreased in SDF muscle with both types of training, with maximum diameters greater for horses after underwater versus conventional treadmill training. No change was identified in minimum fiber diameters. CONCLUSIONS AND CLINICAL RELEVANCE SETs involving near-maximal exertion resulted in an anaerobic response in SDF and gluteal muscles of horses. Eight weeks of conventional or underwater treadmill training resulted in minor changes in type I muscle fiber sizes, with no effect on muscle metabolic or heart rate responses to SETs. After rehabilitation involving underwater treadmills, training at progressing speeds is recommended for horses to develop the required fitness for speed work.

OBJECTIVE To evaluate the pharmacokinetics of hydrocodone (delivered in combination with acetaminophen) and tramadol in dogs undergoing tibial plateau leveling osteotomy (TPLO). ANIMALS 50 client-owned dogs. PROCEDURES Dogs were randomly assigned to receive tramadol hydrochloride (5 to 7 mg/kg, PO, q 8 h; tramadol group) or hydrocodone bitartrate–acetaminophen (0.5 to 0.6 mg of hydrocodone/kg, PO, q 8 h; hydrocodone group) following TPLO with standard anesthetic and surgical protocols. Blood samples were collected for pharmacokinetic analysis of study drugs and their metabolites over an 8-hour period beginning after the second dose of the study medication. RESULTS The terminal half-life, maximum serum concentration, and time to maximum serum concentration for tramadol following naïve pooled modeling were 1.56 hours, 155.6 ng/mL, and 3.90 hours, respectively. Serum concentrations of the tramadol metabolite O-desmethyltramadol (M1) were low. For hydrocodone, maximum serum concentration determined by naïve pooled modeling was 7.90 ng/mL, and time to maximum serum concentration was 3.47 hours. The terminal half-life for hydrocodone was 15.85 hours, but was likely influenced by delayed drug absorption in some dogs and may not have been a robust estimate. Serum concentrations of hydromorphone were low. CONCLUSIONS AND CLINICAL RELEVANCE The pharmacokinetics of tramadol and metabolites were similar to those in previous studies. Serum tramadol concentrations varied widely, and concentrations of the active M1 metabolite were low. Metabolism of hydrocodone to hydromorphone in dogs was poor. Further study is warranted to assess variables that affect metabolism and efficacy of these drugs in dogs.

OBJECTIVE To determine the effect of dantrolene premedication on various cardiovascular and biochemical variables and recovery in isoflurane-anesthetized horses. ANIMALS 6 healthy horses. PROCEDURES Each horse was anesthetized twice with a 21- to 28-day washout period between anesthetic sessions. Food was not withheld from horses before either session. During each session, dantrolene (6 mg/kg in 2 L of water) or water (2 L) was administered via a nasogastric tube 1 hour before anesthesia was induced. Anesthesia was maintained with isoflurane for 90 minutes, during which blood gas analyses and lithium-dilution cardiac output (CO) measurements were obtained every 10 minutes. Serum creatine kinase activity was measured before and at 4, 8, and 12 hours after anesthesia. RESULTS When horses were premedicated with dantrolene, CO at 25, 35, and 45 minutes after induction of anesthesia was significantly lower than that when horses were premedicated with water after which time difficulty in obtaining valid measurements suggested a continued decrease in CO; plasma potassium concentration progressively increased during anesthesia, whereas serum creatine kinase activity remained fairly stable and within reference limits through 12 hours after anesthesia; and 2 of 6 horses developed cardiac arrhythmias that required medical intervention. The quality of anesthetic recovery was slightly better when horses were premedicated with dantrolene versus water, although the time required for recovery did not differ significantly between treatments. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that dantrolene premedication prevented muscle damage without affecting anesthetic recovery but impaired CO and precipitated hyperkalemia and cardiac arrhythmias in healthy isoflurane-anesthetized horses.

OBJECTIVE To generate reference intervals for ECG variables in clinically normal chimpanzees (Pan troglodytes). ANIMALS 100 clinically normal (51 young [< 10 years old] and 49 adult [≥ 10 years old]) wild-born chimpanzees. PROCEDURES Electrocardiograms collected between 2009 and 2013 at the Tchimpounga Chimpanzee Rehabilitation Centre were assessed to determine heart rate, PR interval, QRS duration, QT interval, QRS axis, P axis, and T axis. Electrocardiographic characteristics for left ventricular hypertrophy (LVH) and morphology of the ST segment, T wave, and QRS complex were identified. Reference intervals for young and old animals were calculated as mean ± 1.96•SD for normally distributed data and as 5th to 95th percentiles for data not normally distributed. Differences between age groups were assessed by use of unpaired Student t tests. RESULTS Reference intervals were generated for young and adult wild-born chimpanzees. Most animals had sinus rhythm with small or normal P wave morphology; 24 of 51 (47%) young chimpanzees and 30 of 49 (61%) adult chimpanzees had evidence of LVH as determined on the basis of criteria for humans. CONCLUSIONS AND CLINICAL RELEVANCE Cardiac disease has been implicated as the major cause of death in captive chimpanzees. Species-specific ECG reference intervals for chimpanzees may aid in the diagnosis and treatment of animals with, or at risk of developing, heart disease. Chimpanzees with ECG characteristics outside of these intervals should be considered for follow-up assessment and regular cardiac monitoring.

Meadow voles (Microtus pennsylvanicus) are permissive to chronic wasting disease (CWD) infection, but their susceptibility to other transmissible spongiform encephalopathies (TSEs) is poorly characterized. In this initial study, we intracerebrally challenged 6 meadow voles with 2 isolates of sheep scrapie. Three meadow voles acquired a TSE after the scrapie challenge and an extended incubation period. The glycoform profile of proteinase K-resistant prion protein (PrPres) in scrapie-sick voles remained similar to the sheep inocula, but differed from that of voles clinically affected by CWD. Vacuolization patterns and disease-associated prion protein (PrPSc) deposition were generally similar in all scrapie-affected voles, except in the hippocampus, where PrPSc staining varied markedly among the animals. Our results demonstrate that meadow voles can acquire a TSE after intracerebral scrapie challenge and that this species could therefore prove useful for characterizing scrapie isolates.

OBJECTIVE To evaluate pharmacokinetics of ammonium tetrathiomolybdate (TTM) after IV and oral administration to dogs and effects of TTM administration on trace mineral concentrations. ANIMALS 8 adult Beagles and Beagle crossbreds (4 sexually intact males and 4 sexually intact females). PROCEDURES Dogs received TTM (1 mg/kg) IV and orally in a randomized crossover study. Serum molybdenum and copper concentrations were measured via inductively coupled plasma mass spectrometry in samples obtained 0 to 72 hours after administration. Pharmacokinetics was determined via noncompartmental analysis. RESULTS For IV administration, mean ± SD terminal elimination rate constant, maximum concentration, area under the curve, and half-life were 0.03 ± 0.01 hours−1, 4.9 ± 0.6 μg/mL, 30.7 ± 5.4 μg/mL•h, and 27.7 ± 6.8 hours, respectively. For oral administration, mean ± SD terminal elimination rate constant, time to maximum concentration, maximum concentration, area under the curve, and half-life were 0.03 ± 0.01 hours−1, 3.0 ± 3.5 hours, 0.2 ± 0.4 μg/mL, 6.5 ± 8.0 μg/mL•h, and 26.8 ± 8.0 hours, respectively. Oral bioavailability was 21 ± 22%. Serum copper concentrations increased significantly after IV and oral administration. Emesis occurred after IV (2 dogs) and oral administration (3 dogs). CONCLUSIONS AND CLINICAL RELEVANCE Pharmacokinetics for TTM after a single IV and oral administration was determined for clinically normal dogs. Absorption of TTM after oral administration was variable. Increased serum copper concentrations suggested that TTM mobilized tissue copper. Further studies will be needed to evaluate the potential therapeutic use of TTM in copper-associated chronic hepatitis of dogs.

OBJECTIVE To evaluate the impact of gentamicin, silver, or both additives in polymethylmethacrylate (PMMA) beads on methicillin-resistant Staphylococcus pseudintermedius (MRSP) biofilm formation in vitro. SAMPLE 4 preparations of PMMA beads (formed with no additive [control], gentamicin, silver, and gentamicin and silver). PROCEDURES Beads from each group were exposed to 10 MRSP isolates known to be strong biofilm formers. Following incubation, the beads were rinsed to remove planktonic bacteria, then sonicated to dislodge biofilm-associated bacteria. Resulting suspensions were serially diluted, plated on blood agar, and incubated overnight; CFUs were counted. Variance of mean CFU counts following log10 transformation was analyzed among PMMA groups. RESULTS None of the PMMA additives tested completely inhibited MRSP biofilm formation. There was a significant effect of gentamicin and gentamicin plus silver on this variable, compared with controls, but not of silver alone. There was no difference between gentamicin and gentamicin plus silver. When only isolates not susceptible to gentamicin were evaluated, there were no significant differences among PMMA additive groups. Within gentamicin-susceptible isolates, there was an impact of gentamicin and gentamicin plus silver, but no impact of silver alone and no difference between gentamicin and gentamicin plus silver. CONCLUSIONS AND CLINICAL RELEVANCE Gentamicin-impregnated PMMA was effective at reducing biofilm formation of gentamicin-susceptible MRSP isolates but had no effect on isolates not susceptible to gentamicin. Silver-impregnated PMMA had no effect on MRSP biofilm formation. Results suggested that gentamicin-impregnated PMMA may not be effective in vivo against MRSP isolates not susceptible to gentamicin. Antibacterial efficacy of silver should not be assumed without proper testing of the target bacteria and specific silver compound.