Objective—To determine whether echocardiographic variables differed between successful (elite) and less successful (nonelite) Arabian endurance horses. Animals—34 Arabian horses that competed in endurance racing. Procedures—Horses were assigned to either an elite or nonelite group on the basis of results of a previous competition, and a standardized echocardiographic examination was performed on each horse within 1 to 4 weeks after that competition. Multivariable logistic regression with backward stepwise elimination was used to create a prediction model for the determination of horse status (elite or nonelite) as a function of the measured echocardiographic variables. Results—The elite and nonelite groups consisted of 23 and 11 horses, respectively. One horse in the nonelite group had a frequent ventricular dysrhythmia that could have negatively affected its performance and rider's safety, whereas none of the horses in the elite group had remarkable cardiac abnormalities. The left ventricular internal diameter during systole and diastole and left ventricular mass and stroke volume were significantly greater for horses in the elite group, compared with those for horses in the nonelite group. The final logistic regression model correctly predicted the horse status for all of the horses in the elite group and 8 of 11 horses in the nonelite group. Conclusions and Clinical Relevance—Results indicated that heart size was significantly associated with performance for Arabian endurance horses in a manner similar to findings for Thoroughbred and Standardbred racehorses in active competition.

Objective—To determine the pharmacokinetics of cefovecin sodium after SC administration to Hermann's tortoises (Testudo hermanni). Animals—23 healthy adult Hermann's tortoises (15 males and 8 females). Procedures—Cefovecin (8.0 mg/kg) was injected once in the subcutis of the neck region of Hermann's tortoises, and blood samples were obtained at predetermined time points. Plasma cefovecin concentrations were measured via ultraperformance liquid chromatography coupled to tandem mass spectrometry, and pharmacokinetic parameters were calculated with a noncompartmental model. Plasma protein concentration was quantified, and the percentage of cefovecin bound to protein was estimated with a centrifugation technique. Results—Cefovecin was absorbed rapidly, reaching maximum plasma concentrations between 35 minutes and 2 hours after administration, with the exception of 1 group, in which it was reached after 4 hours. The mean ± SD time to maximum concentration was 1.22 ± 1.14 hours; area under the concentration-time curve was 220.35 ± 36.18 h•μg/mL The mean protein-bound fraction of cefovecin ranged from 41.3% to 47.5%. No adverse effects were observed. Conclusions and Clinical Relevance—Administration of a single dose of cefovecin SC appeared to be well-tolerated in this population of tortoises. Results of pharmacokinetic analysis indicated that the 2-week dosing interval suggested for dogs and cats cannot be considered effective in tortoises; however, further research is needed to determine therapeutic concentrations of the drug and appropriate dose ranges.

Objective - To compare accuracy of a noninvasive single-plane fluoroscopic technique with radiostereometric analysis (RSA) for determining 3-D femorotibial poses in a canine cadaver with normal stifle joints. Sample- Right pelvic limb from a 25-kg adult mixed-breed dog. Procedures- A CT scan of the limb was obtained before and after metal beads were implanted into the right femur and tibia. Orthogonal fluoroscopic images of the right stifle joint were acquired to simulate a biplanar fluoroscopic acquisition setup. Images were obtained at 5 flexion angles from 110° to 150° to simulate a gait cycle; 5 cycles were completed. Joint poses were calculated from the biplanar images by use of RSA with CT-derived beaded bone models and compared with measurements obtained by use of CT-derived nonbeaded bone models matched to single-plane, lateral-view fluoroscopic images. Single-plane measurements were performed by 2 observers and repeated 3 times by the primary observer. Results- Mean absolute differences between the single-plane fluoroscopic analysis and RSA measurements were 0.60, 1.28, and 0.64 mm for craniocaudal, proximodistal, and mediolateral translations, respectively, and 0.63°, 1.49°, and 1.58° for flexion-extension, abduction-adduction, and internal-external rotations, respectively. Intra- and interobserver repeatability was strong with maximum mean translational and rotational SDs of 0.52 mm and 1.36°, respectively. Conclusions and Clinical Relevance- Results suggested that single-plane fluoroscopic analysis performed by use of CT-derived bone models is a valid, noninvasive technique for accurately measuring 3-D femorotibial poses in dogs.

Objective- To compare the mechanical properties of laryngeal tie-forward (LTF) surrogate constructs prepared with steel fixtures and No. 5 braided polyester or braided polyethylene by use of a standard or a modified suture placement technique. Sample- 32 LTF surrogate constructs. Procedures- Surrogate constructs were prepared with steel fixtures and sutures (polyester or polyethylene) by use of a standard or modified suture placement technique. Constructs underwent single-load-to-failure testing. Maximal load at failure, elongation at failure, stiffness, and suture breakage sites were compared among constructs prepared with polyester sutures by means of the standard (n = 10) or modified (10) technique and those prepared with polyethylene sutures with the standard (6) or modified (6) technique. Results- Polyethylene suture constructs had higher stiffness, higher load at failure, and lower elongation at failure than did polyester suture constructs. Constructs prepared with the modified technique had higher load at failure than did those prepared with the standard technique for both suture materials. All sutures broke at the knot in constructs prepared with the standard technique. Sutures broke at a location away from the knot in 13 of 16 constructs prepared with the modified technique (3 such constructs with polyethylene sutures broke at the knot). Conclusions and Clinical Relevance- Results suggested LTF surrogate constructs prepared with polyethylene sutures or the modified technique were stronger than those prepared with polyester sutures or the standard technique.

The objective of this study was to compare the bursting strength (BS) and mode of failure (MF) of ventral midline (VM) celiotomies closed with USP 7 polydioxanone (7PD) in 1 or 2 simple continuous sections. A bursting strength model, consisting of inserting and inflating a 200-L polyurethane bladder through a 25-cm VM celiotomy, was used on 15 fresh equine cadavers. Celiotomies were closed using 7PD in 2 separate sections (4 knots), 2 continuous sections (3 knots), or a single section (2 knots) using a simple continuous pattern. The horses’ signalment, body weight, number of total knots, MF, and BS were recorded and analyzed statistically for interactions. No difference was found between the BS of VM celiotomies closure types (P = 0.4). All celiotomy/suture constructs failed at the abdominal wall. The celiotomy closure types evaluated in this study provided a secure method of closure in VM celiotomies in vivo.

A study of Ontario swine farms positive for Porcine reproductive and respiratory syndrome virus (PRRSV) tested the association between genetic similarity of the virus and similarity of clinical signs reported by the herd owner. Herds were included if a positive result of polymerase chain reaction for PRRSV at the Animal Health Laboratory at the University of Guelph, Guelph, Ontario, was found between September 2004 and August 2007. Nucleotide-sequence similarity and clinical similarity, as determined from a telephone survey, were calculated for all pairs of herds. The Mantel test indicated that clinical similarity and sequence similarity were weakly correlated for most clinical signs. The generalized additive model indicated that virus homology with 2 vaccine viruses affected the association between sequence similarity and clinical similarity. When the data for herds with vaccine-like virus were removed from the dataset there was a significant association between virus similarity and similarity of the reported presence of abortion, stillbirth, preweaning mortality, and sow/boar mortality. Ownership similarity was also found to be associated with virus similarity and with similarity of the reported presence of sows being off-feed, nursery respiratory disease, nursery mortality, finisher respiratory disease, and finisher mortality. These results indicate that clinical signs of PRRS are associated with PRRSV genotype and that herd ownership is associated with both of these.

Susceptibility results for Pasteurella multocida and Streptococcus suis isolated from swine clinical samples were obtained from January 1998 to October 2010 from the Animal Health Laboratory at the University of Guelph, Guelph, Ontario, and used to describe variation in antimicrobial resistance (AMR) to 4 drugs of importance in the Ontario swine industry: ampicillin, tetracycline, tiamulin, and trimethoprim–sulfamethoxazole. Four temporal data-analysis options were used: visualization of trends in 12-month rolling averages, logistic-regression modeling, temporal-scan statistics, and a scan with the “What’s strange about recent events?” (WSARE) algorithm. The AMR trends varied among the antimicrobial drugs for a single pathogen and between pathogens for a single antimicrobial, suggesting that pathogen-specific AMR surveillance may be preferable to indicator data. The 4 methods provided complementary and, at times, redundant results. The most appropriate combination of analysis methods for surveillance using these data included temporal-scan statistics with a visualization method (rolling-average or predicted-probability plots following logistic-regression models). The WSARE algorithm provided interesting results for quality control and has the potential to detect new resistance patterns; however, missing data created problems for displaying the results in a way that would be meaningful to all surveillance stakeholders.

Specific contrast ultrasound is widely applied in diagnostic procedures on humans but remains underused in veterinary medicine. The objective of this study was to evaluate the use of microbubble-based contrast for rapid ultrasonographic diagnosis of thrombosis in small animals, using male New Zealand white rabbits (average weight about 3.5 kg) as a model. It was hypothesized that the use of microbubble-based contrast agents will result in a faster and more precise diagnosis in our model of thrombosis. A pro-coagulant environment had been previously established by combining endothelial denudation and external vessel wall damage. Visualization of thrombi was achieved by application of contrast microbubbles [sterically stabilized, phospholipid-based microbubbles filled with sulfur hexafluoride (SF6) gas] and ultrasonography. As a result, rapid and clear diagnosis of thrombi in aorta abdominalis was achieved within 10 to 30 s (mean: 17.3 s) by applying microbubbles as an ultrasound contrast medium. In the control group, diagnosis was not possible or took 90 to 180 s. Therefore, sterically stabilized microbubbles were found to be a suitable contrast agent for the rapid diagnosis of thrombi in an experimental model in rabbits. This contrast agent could be of practical importance in small animal practice for rapid diagnosis of thrombosis.

Objective- To compare accuracy of a noninvasive single-plane fluoroscopic analysis technique with radiostereometric analysis (RSA) for determining 3-D femorotibial poses in a canine cadaver stifle joint treated by tibial-plateau-leveling osteotomy (TPLO). Sample- Left pelvic limb from a 25-kg adult mixed-breed dog. Procedures- A CT scan of the left pelvic limb was performed. The left cranial cruciate ligament was transected, and a TPLO was performed. Radiopaque beads were implanted into the left femur and tibia, and the CT scan was repeated. Orthogonal fluoroscopic images of the left stifle joint were acquired at 5 stifle joint flexion angles ranging from 110° to 150° to simulate a gait cycle; 5 gait cycles were completed. Joint poses were calculated from the biplanar images by use of a digitally modified RSA and were compared with measurements obtained by use of hybrid implant-bone models matched to lateral-view fluoroscopic images. Single-plane measurements were performed by 2 observers and repeated 3 times by the primary observer. Results- Mean absolute differences between results of the single-plane fluoroscopic analysis and modified RSA were 0.34, 1.05, and 0.48 mm for craniocaudal, proximodistal, and mediolateral translations, respectively, and 0.56°, 0.85°, and 1.08° for flexion-extension, abduction-adduction, and internal-external rotations, respectively. Intraobserver and interobserver mean SDs did not exceed 0.59 mm for all translations and 0.93° for all rotations. Conclusions and Clinical Relevance- Results suggested that single-plane fluoroscopic analysis by use of hybrid implant-bone models may be a valid, noninvasive technique for accurately measuring 3-D femorotibial poses in dogs treated with TPLO.

Objective-To determine the pharmacokinetics of ceftiofur crystalline-free acid (CCFA) following SC administration of a single dose to sheep. Animals-9 healthy adult female Suffolk-crossbred sheep. Procedures-Each sheep was administered 6.6 mg of CCFA/kg, SC, in the cervical region once. Serial blood samples were collected at predetermined intervals for 14 days. Serum concentration of ceftiofur free-acid equivalents (CFAE) was determined by high-performance liquid chromatography. Pharmacokinetic parameters were determined by compartmental and noncompartmental methods. Results-Pharmacokinetics for CCFA following SC administration in sheep was best described with a 1-compartment model. Mean +/- SD area under the concentration-time curve from time 0 to infinity, peak serum concentration, and time to peak serum concentration were 206.6 +/- 24.8 μ•h/mL, 2.4 +/- 0.5 μg/mL, and 23.1 +/- 10.1 h, respectively. Serum CFAE concentrations ≥ 1 μg/mL (the target serum CFAE concentration for treatment of disease caused by Mannheimia haemolytica and Pasteurella multocida) were maintained for 2.6 to 4.9 days. No significant adverse reactions to CCFA administration were observed. Conclusions and Clinical Relevance-Results indicated that adequate therapeutic serum concentrations of CFAE for treatment of disease caused by M haemolytica and P multocida were achieved in sheep following SC administration of a single dose (6.6 mg/kg) of CCFA. Thus, CCFA might be useful for the treatment of common respiratory tract pathogens in sheep.