Ultrasonographic Appearance of Dandy Walker-Like Syndrome in a Boston Terrier

Congenital cerebellar disorders can be caused by in utero or neonatal infections, genetic aberrations causing malformations, and neurodegenerative processes. Most congenital cerebellar disorders are diagnosed definitively with histopathology. However, antemortem diagnosis of cerebellar malformations can be made by imaging the brain. This paper describes the antemortem appearance of a congenital cerebellar malformation in a Boston Terrier puppy on ultrasound images. This appearance was compared with the postmortem findings that were comparable to Dandy Walker Syndrome in humans. A previous report of this syndrome in Boston Terriers suggests the problem may be inherited in this breed.     

A survey on bloat in southern Australian beef production systems

Frothy bloat, associated predominantly with grazing legume-based pastures, is considered the second most costly disease in beef cattle in southern Australia, costing $84.4 M annually. It frequently results in the sudden death of cattle. In response to concerns from cattle producers, an online survey was conducted in southern Australia in late 2020 to determine the impact of bloat, identify risk factors and determine the efficacy of current preventive measures. For 217 responses, over two-thirds (70%) of producers reported bloat occurring in the previous 12 months, with estimated morbidity and mortality rates of 3.7% and 5.0% respectively. Bloat was associated with clover or clover-dominant paddocks (79%) and was not associated with grass or grass-dominant pastures or low clover pastures (92%) nor grazing crops (27%). For bloat that occurred in the past 12 months, cattle were very commonly grazing on clover or clover-dominant paddocks (90%) and occasionally lucerne-dominated paddocks (7%). Two-thirds of producers reported having preventive measures in place when losses occurred. Bayesian Network analysis confirmed that grazing clover-based pastures for more than 7 days, yearling cattle and the months of July–September were the main risk factors for bloat occurrence, with pasture type (clover) being the most important. Conversely, no clear relationship between weather conditions and bloat occurrence was evident. This survey highlights the known risk of clover-based pastures for causing bloat in cattle, and that losses occur in many cases despite preventive measures being used. This suggests that current methods for preventing bloat in cattle are suboptimal.     

DOPPLER MEASUREMENT OF HEPATIC ARTERIAL FLOW IN DOGS: TECHNIQUE AND PRELIMINARY FINDINGS

The common hepatic artery in 10 healthy adult beagles, 20 healthy pups (13 Deerhounds and seven Irish Wolfhounds), and seven dogs with either a congenital or acquired hepatic disorder was examined by duplex-Doppler ultrasonography. Peak systolic velocity (Vs), resistive index (RI), pulse rate, angle of insonation, and sample volume depth were recorded. Measurements in Beagles were made after a 24 h fast and repeated 2 h after feeding. The mean Vs and RI in fasted Beagles were 1.5 m/s (range 1.1-2.3 m/s) and 0.68 (range 0.62-0.74), respectively. Postprandially, there were no significant differences in any of these variables. Mean Vs and RI were lower in pups: 1.0 m/s (range 0.8-1.3 m/s) and 0.59 (range 0.46-0.65), respectively (P < .001). Two dogs with congenital arterioportal fistula had higher mean Vs (P < .001) and lower mean RI (P < .05) than normal pups. No significant differences were detected between normal Beagles, three dogs with portal vein thrombosis, and two dogs with acquired hepatic insufficiency. Differences in measured hepatic blood flow in dogs of different age or breed will complicate diagnostic use of hepatic arterial Doppler measurements.     

Absorption of enrofloxacin and marbofloxacin after oral and subcutaneous administration in diseased koalas (Phascolarctos cinereus)

Griffith, J.E., Higgins, D.P., Li, K.M., Krockenberger, M.B., Govendir, M. Absorption of enrofloxacin and marbofloxacin after oral and subcutaneous administration in diseased koalas (Phascolarctos cinereus). J. vet. Pharmacol. Therap. 33 , 595–604. Koalas (n = 43) were treated daily for up to 8 weeks with enrofloxacin: 10 mg/kg subcutaneously (s.c.), 5 mg/kg s.c., or 20 mg/kg per os (p.o.); or marbofloxacin: 1.0–3.3 mg/kg p.o., 10 mg/kg p.o. or 5 mg/kg s.c. Serial plasma drug concentrations were determined on day 1 and again at approximately 2 weeks, by liquid chromatography. The median (range) plasma maximum concentrations (C_max) for enrofloxacin 5 mg/kg s.c. and 10 mg/kg s.c. were 0.83 (0.68–1.52) and 2.08 (1.34–2.96) μg/mL and the median (range) T_max were 1.5 h (1–2) and 1 h (1–2) respectively. Plasma concentrations of orally dosed marbofloxacin were too low to be quantified. Oral administration of enrofloxacin suggested absorption rate limited disposition pharmacokinetics; the median (range) C_max for enrofloxacin 20 mg/kg p.o. was 0.94 (0.76–1.0) μg/mL and the median (range) T_max was 4 h (2–8). Oral absorption of both drugs was poor. Plasma protein binding for enrofloxacin was 55.4 ± 1.9% and marbofloxacin 49.5 ± 5.3%. Elevations in creatinine kinase activity were associated with drug injections. Enrofloxacin and marbofloxacin administered at these dosage and routes are unlikely to inhibit the growth of chlamydial pathogens in vivo.     

Effect of Recombinant Bovine Somatotropin on Plasma Concentrations of Insulin‐like Growth Factor I,Insulin and Membrane Integrity of Bull Spermatozoa

This study aimed to evaluate the effect of the exogenous recombinant bovine somatotropin (rbST) on plasma concentrations of insulin‐like growth factor I (IGF‐I), insulin and semen quality of bulls. Twenty bulls (Aberdeen Angus and Brangus) were divided by breed into two groups. Placebo group was injected with NaCl 0.9% (s.c.) and treatment group with rbST (s.c., 500 mg) at days 0 and 14 of the experiment. Immediately after semen collection, blood samples were taken on days 0, 14, 28, 42 and 56 of the experiment. Semen was also collected on day 70 of the experiment. Evaluation of sperm motility was performed at pre‐freezing and post‐thawing stage, whereas assessment of sperm membrane integrity was performed after freezing and thawing. Analysis of data revealed that the effect of treatment and treatment‐by‐collection day on plasma concentrations of IGF‐I and insulin was not significant. However, mean plasma concentrations of IGF‐I and insulin were affected (p < 0.0001) by days of blood sampling. Effect of treatment and treatment‐by‐collection day on motility of spermatozoa was similar (p > 0.05) at pre‐freezing and post‐thawing stage. Intactness of plasmalemma and tail membrane of spermatozoa at post‐thawing stage was higher (p < 0.05) in rbST‐treated group than in control. In conclusion, rbST did not affect plasma concentrations of IGF‐I and insulin, however, it did improve post‐thaw sperm membrane integrity.     

Pharmacokinetics of meloxicam in koalas (Phascolarctos cinereus) after intravenous,subcutaneous and oral administration

The pharmacokinetic profile of meloxicam in clinically healthy koalas (n = 15) was investigated. Single doses of meloxicam were administered intravenously (i.v.) (0.4 mg/kg; n = 5), subcutaneously (s.c.) (0.2 mg/kg; n = 1) or orally (0.2 mg/kg; n = 3), and multiple doses were administered to two groups of koalas via the oral or s.c. routes (n = 3 for both routes) with a loading dose of 0.2 mg/kg for day 1 followed by 0.1 mg/kg s.i.d for a further 3 days. Plasma meloxicam concentrations were quantified by high‐performance liquid chromatography. Following i.v. administration, meloxicam exhibited a rapid clearance (CL) of 0.44 ± 0.20 (SD) L/h/kg, a volume of distribution at terminal phase (V_z) of 0.72 ± 0.22 L/kg and a volume of distribution at steady state (V_ss) of 0.22 ± 0.12 L/kg. Median plasma terminal half‐life (t_1/2) was 1.19 h (range 0.71–1.62 h). Following oral administration either from single or repeated doses, only maximum peak plasma concentration (C_max 0.013 ± 0.001 and 0.014 ± 0.001 μg/mL, respectively) was measurable [limit of quantitation (LOQ) >0.01 μg/mL] between 4–8 h. Oral bioavailability was negligible in koalas. Plasma protein binding of meloxicam was ~98%. Three meloxicam metabolites were detected in plasma with one identified as the 5‐hydroxy methyl derivative. This study demonstrated that koalas exhibited rapid CL and extremely poor oral bioavailability compared with other eutherian species. Accordingly, the currently recommended dose regimen of meloxicam for this species appears inadequate.