OSTEODYSTROPHIA FIBROSA IN HORSES AT PASTURE IN QUEENSLAND: FIELD AND LABORATORY OBSERVATIONS

Horses grazing manily Cenchrus ciliaris and/or Panicum maximum var. trichoglume pastures on over 30 properties in southern central Queensland developed lesions of osteodystrophia fibrosa. Horses on individual properties in coastal Queensland grazing Setaria anceps, Brachiaria mutica or Pennisetum clandestinum also developed the disease. Ill-thrift, lameness, and fibrous swellings of nasal bones, maxillae and mandibles were observed. Calcium and phosphorus levels of pasture were normal but all the above pasture species contained oxalates which were suspected of causing the disease.     

Aragonite Crystals within Codiacean Algae: Distinctive Morphology and Sedimentary Implications

Morphologic studies of single crystals of aragonite within Codiacean algae reveal characteristic crystal forms produced by two distinctly different modes of calcification. Diagnostic serrated crystals (1 micrometer in length) of aragonite originating within the extracellular sheaths of capitular filaments are incorporated into modern lime sediments and may serve as effective tracers for particles of algal origin. Intracellular calcification within Penicillus dumetosus, previously unueported, is represented by doubly terminated aragonite crystals ranging in size from 48 to 160 micrometers.     

Patterns in the modern decline of western Australia''s vertebrate fauna: Causes and conservation implications

The conservation status of terrestrial vertebrates occurring on the mainland of Western Australia was assessed. Extinctions and declines are virtually confined to non-flying mammals with mean adult body weights between 35 g and 4200 g. Variation in patterns of attrition within this critical weight range (CWR) can be explained almost entirely by a combination of regional patterns in rainfall and, to a lesser extent, species' habitat and dietary preferences. Similar patterns of mammal attrition were recognisable throughout the continent, except that the CWR was 35 to 5500 g.

Environmental changes since European settlement have emulated an increase in aridity by reducing the environmental productivity available to vertebrates. These include the diversion of environmental resources to humans and introduced species, and a reduction in vegetative cover by exotic herbivores and changed fire regimes. Our analyses support the view that the reduction in available productivity has caused CWR mammals to suffer the greatest attrition because of their limited mobility, but relatively high daily metabolic requirements. The direct elimination of confined populations of mammals by exotic predators has exacerbated this attrition. We derive priorities for the conservation of Australian mammals.     

Does Amia Calva aestivate?

During gradual air exposure, Amia calva show no reduction in oxygen consumption, no increase in plasma urea levels or in urea excretion. Blood pH remains constant, and plasma total CO₂, P_{CO 2}, HCO₃ ^-. total ammonia and NH₃ concentrations all rise significantly. Exposure to 923 μmol/l NH₄Cl does not elicit an increase in urea production or airbreathing. Aquatic hypoxia without access to air does not cause a reduction in aerobic metabolism, and moderate levels result in death. These results suggest that Amia are incapable of aestivation, due to an inability to detoxify ammonia to urea and reduce metabolism, and die following three to five days of air exposure.     

Contents of Volume 10

Volume Contents

Contents of Volume 10     

Quantitative and qualitative comparison of three scoring systems for assessing recovery quality after general anaesthesia in horses

Objective To assess the reproducibility and repeatability of two commonly used recovery quality scoring systems and compare them with those of a novel system based on a greater number of objective criteria. Animals The video‐recorded recoveries of ten client‐owned horses selected from all recovery recordings taken between September 2005 and March 2006 at the Royal (Dick) School of Veterinary Studies. Materials and methods A digital versatile disc (DVD) was produced using edited video recordings of ten horses recovering from general anaesthesia. Twelve experienced equine anaesthetists (raters) studied the DVD on three occasions, and scored the recovery quality of each horse using one of three scoring systems (P, D or E) on each occasion. The process was repeated 6 months later (t = 6) to measure intra‐observer reliability (repeatability). At first use (t = 0) raters were asked to comment on the advantages and disadvantages of each system. Results Inter‐rater variability was limited for each system: at each observation period raters accounted for 0.3–4.4% variation. System P was insensitive to differences between recoveries. In system D, score variability increased as recovery quality deteriorated. Intra‐rater variability varied with system: using system P, raters provided consistent scores between the observation periods for some, but not all horses (‘horse’ and ‘rater’ accounted for 9.7% and 1.9% of variation respectively). Raters were less consistent between t = 0 and t = 6 using system D, but each horse was scored with similar consistency. System E produced little variation at the level of horse (1.0%) and rater (1.9%). Raters broadly agreed on the principle advantages and disadvantages of the three systems. Conclusions and clinical relevance The systems examined showed reliability and reproducibility but practicality and simplicity of use appeared to be inextricably linked with imprecision. Further work is required to produce a suitable recovery quality scoring system.