Duration of the persistent activity of moxidectin against Haemonchus contortus in sheep

SUMMARY Weaned lambs were infected with Haemonchus contortus 35,28,21,14 and 7 days after treatment with moxidectin at 0.2 mg/kg and 35 and 14 days after treatment with ivermectin at the same dose rate. Worm counts 14 days after infection showed that moxidectin prevented the establishment of over 99% of infective larvae for 28 days and reduced the establishment rate at 35 days by 96%, relative to ivermectin. There was no difference in the protective efficacy of ivermectin at 14 or 35 days. The persistence of moxidectin is likely to provide advantages in nematode control, particularly when used as a strategic early summer treatment or as a pre-lambing treatment to ewes. Implications of the persistent activity of moxidectin for the development of resistance during the decay phase are discussed.     

A case‐based review of a simplified quantitative approach to acid‐base analysis

Objective – To present a simplified quantitative approach to acid‐base analysis and to demonstrate its clinical utility. Data Sources – Original research articles and textbooks. Data Synthesis – A simplified quantitative approach to acid‐base analysis is presented, which is derived from the Fencl‐Stewart approach and calculates the magnitude of the effect on the standardized base excess (SBE) of 5 separate variables: (1) a free water effect (marked by sodium concentration), (2) an effect marked by the chloride concentration, (3) an albumin effect, (4) a lactate effect, and (5) a phosphate effect. Six clinical cases with acid‐base abnormalities are presented in which the quantitative approach provides information that is not apparent from the traditional approach. Conclusion – This simplified quantitative approach provides a comprehensive evaluation of complex acid‐base disorders, identifies individual processes and their relative influence on SBE, and aids in the development of an appropriate therapeutic plan.     

Concurrent Diseases and Conditions in Dogs with Splenic Vein Thrombosis

Background: Splenic venous thrombosis (SVT) is usually considered an incidental finding on abdominal ultrasound examination but can indicate the presence of underlying disease. Concurrent disease processes and conditions in dogs with SVT have not been identified previously. Objectives: To identify concurrent diseases and conditions in dogs with SVT. Animals: Eighty dogs with SVT. Methods: Retrospective review. Medical records from 1994 through 2008 were searched for dogs with SVT identified by ultrasound examination. These records were then reviewed for signalment, medical history, clinicopathologic testing, diagnostic imaging, and clinical diagnosis. Results: The most common concurrent conditions were neoplasia (54%), exogenous corticosteroid administration (43%), systemic inflammatory response syndrome (26%), disseminated intravascular coagulation (20%), pancreatitis (18%), and immune‐mediated disease (16%). The most common neoplastic disease was lymphoma, and the most common immune‐mediated disease was immune‐mediated hemolytic anemia. Protein‐losing nephropathy and naturally occurring hyperadrenocorticism were identified in <10% of the dogs. Concurrent splenic infarcts were identified in 33% of dogs, and concurrent portal vein thrombi were found in 18% of dogs. Conclusions: SVT is a sonographic finding of clinical importance, and dogs with SVT can have 1 or more coexisting diseases.     

Management and assessment of prognosis after gastrocnemius disruption in Thoroughbred foals: 28 cases (1993–2007)

Reasons for performing study: Few studies have evaluated the athletic prognosis of foals affected by gastrocnemius disruption. Objective: To examine the diagnosis and management of gastrocnemius disruption in Thoroughbred (TB) foals, determine short‐term survival rate and assess future racing performance. The hypothesis was that Thoroughbred foals with gastrocnemius disruption are able to perform as racehorses comparably to their age matched maternal siblings. Methods: The medical records of foals diagnosed with gastrocnemius muscle disruption were reviewed. Information on training and racing was acquired from published works and race records. Paired t tests were utilised to compare performance variables of affected racehorses to their maternal siblings in starts, earnings and earnings/start for their 2‐ and 3‐year‐old racing seasons. Fisher's exact tests were employed to determine the association between sex, limb affected, age on admission, degree of caudal reciprocal apparatus dysfunction, concurrent disease, antibiotic therapy, complications, abscess formation and likelihood of entering training or starting a race. Results: Sample size was too small to detect significant differences in performance variables between affected horses and controls. Of 28 foals, 17 (61%) presented with concomitant illness; foals without concurrent disease were more likely to achieve race training or start a race (P = 0.04); 23 (82%) were short‐term survivors defined as survival to discharge. Of these 23 survivors, 7 were aged <2 years at the time of the study. Eighty‐one percent (13/16) of the survivors that were of racing age were in training or had started a race. Conclusions: In this population, 82% of TB foals affected with gastrocnemius disruption were able to achieve training or start a race. Foals presenting for gastrocnemius disruption have a high prevalence of concurrent disease processes. Potential relevance: The assessment of athletic prognosis and treatment complications provides useful information to clinicians treating gastrocnemius muscle disruption in foals and making recommendations to clientele.     

The Effect of Hetastarch (670/0.75) on Urine Specific Gravity and Osmolality in the Dog

Background: Urine specific gravity (USG) is used clinically to estimate urine osmolality (UOsm). Although USG has been shown to have a linear correlation with UOsm in dogs, the relationship is altered when there are significant numbers of high molecular weight (MW) molecules in the urine.
Hypothesis: USG would no longer predict UOsm in dogs given intravenous hetastarch (670/0.75)(HES).
Animals: Eight healthy employee-owned adult dogs.
Methods: Prospective, controlled experimental study. USG and UOsm were measured every 30 minutes from t=0 minutes to t=360 minutes. Dogs were administered 20mL/kg of either NaCl 0.9% (control group, n=4) or HES (treatment group, n=8) IV over 1 hour starting at t=90 minutes.
Results: There was a decrease in UOsm in both groups starting at t=120 minutes and continuing for the study duration, and there was no significant difference in UOsm between treatment and control groups across all time points. There was an appropriate decrease in USG from t=120 minutes for the control group. In the treatment group, USG increased significantly at t=120 minutes ( P = .0006), t=150 minutes ( P = .0002), and t=180 minutes ( P = .0044). The largest increase in USG occurred at t=150 minutes with a mean USG of 1.070 ± 0.021 (range 1.038-1.104).
Conclusions and clinical importance: Urine specific gravity should not be used to estimate urine solute concentration in dogs following the administration of 20mL/kg of HES. In a clinical setting, the evaluation of USG following this dose of HES may lead to an overestimation of urine concentration.