Programs for surveillance and monitoring of antibacterial residues in Australia, 1989 to 1993

SUMMARY The development of a State-based confirmatory testing capability for antibiotic residues in meat in Australia has allowed the rapid feedback to producers failing to comply with antibiotic maximum residue limits. The identification of problem areas in various categories of livestock, and subsequent focused surveillance programs, has reduced the prevalence of antibacterial residues in both domestic and export meat products. Failure to observe withholding periods of antibacterial drugs after treatment is the most significant cause of non-compliance. In the period July 1991 to June 1993 the compliance rate for antibacterial residues for all species was 99.9%.     

Lymphangiomatosis of the pelvic limb in a Maltese dog

A case of lymphangiomatosis is described affecting the right pelvic limb of an 18-month-old, female Maltese dog. A progressive swelling around the stifle had developed subsequent to a routine tibial crest transposition. The swollen area eventually progressed to involve the entire limb circumferentially, to end abruptly in the mid-metatarsal region. The skin of the affected area was deep red in colour, devoid of hair, and had numerous large, thin-walled vesicles that were easily ruptured and from which a serosan-guineous fluid exuded. The swelling pitted on digital pressure and showed fluctuant mobility. The microscopic appearance of biopsied and post mortem material mimicked that of lymphangioma. However, the signalment, clinical presentation and histological features are consistent with a diagnosis of the recently reported variant of human lymphangiomatosis, lymphangiomatosis of the limb.     

The pathophysiology of ovine fascioliasis: studies on the feed intake and digestibility, body weight and nitrogen balance of sheep given rations of hay or hay plus a pelleted supplement

The effect of Fasciola hepatica on feed intake and digestibility, body weight and nitrogen balance was measured during the course of experimental infections in sheep given a diet of hay or hay with 'concentrate'. A system of paired feeding was used to allow comparisons between infected and control animals. After the sixth week the appetites and body weights of all infected animals declined but both features were more prominent in the group given the diet of hay alone. By week 14 these animals became moribund and were necropsied whereas those given hay with concentrate which had the same fluke burdens, survived until week 20. At necropsy, the loss of weight in both groups was comparable but greater than in their pair-fed uninfected controls, suggesting that inappetence was not solely responsible. Measurements of feed digestibility revealed few differences between infected and control animals on either diet, but nitrogen retention was markedly lower in the infected animals after the eighth week, and sufficient to account for their inferior weight performance. Reduced nitrogen retention was primarily a reflection of a high urinary excretion in the infected animals, faecal excretion remaining unaltered despite the loss of substantial amounts of nitrogen into the gut as a result of the parasites' haematophagic activities.     

INTERNATIONAL STUDY ON Artemia:1 XXI. INVESTIGATIONS INTO WHY SOME STRAINS OF Artemia ARE BETTER FOOD SOURCES THAN OTHERS. FURTHER NUTRITIONAL WORK WITH LARVAE OF THE MUD CRAB,Rhithropanopeus harrisii

In a series of studies conducted by members of the International Study on Artemia, differences in nutritional quality were documented between geographical strains of the brine shrimp Artemia. Concomitant with, and possibly related to nutritional effectiveness are differences in biometric traits and biochemical composition. Since these initial experiments could only hint at causal relationships, a series of experiments were carried out to further our understanding of cause and effect. In one experiment we tried to ascertain whether the factors responsible for poor survival in larvae fed some brine shrimp strains are cumulative throughout larval development or whether there are critical periods when larvae are more sensitive. Our results indicate that the factors contributing to poor growth and survival are cumulative. In a second experiment, we contaminated Brazil Artemia with diel-drin, chlordane and combinations of the two and fed them to mud crab (Rhithropanopeus harrisii) larvae. The levels of contamination were chosen to approximate those suspected of contributing to the poor food value of some brine shrimp strains. In this experiment, however, diel-drin and chlordane contamination appeared to have no effect on growth and survival of R. harrisii larvae. In a third experiment, we fed Utah strain Artemia on Isochrysis galbana for 24 hours and then fed these brine shrimp to mud crab zoeae. Previous work had shown that this regime made Utah Artemia more suitable as a food source for a prawn. However, in our experiments, it did not improve survival of R. harrisii.     

Rates of Tidal Sedimentation from Records of Industrial Pollution and Environmental Magnetism: The Tees Estuary,North-East England

The geochemical and magnetic properties of four sediment cores from Greatham Creek in the Tees estuary, north-east England, provide a record of industrial pollution in the intertidal zone. The peak magnetic concentrations, as interpreted from down-core profiles of χ, SIRM, χ_ARM, and Soft magnetisation, provide a rapid and non-destructive proxy for geochemical analyses. In the absence of variation in grain size or post-depositional migration of sediment pollution, differences in the depth of synchronous peak metal and magnetic concentrations between cores can be attributed to the period and frequency of tidal inundation and, hence, accretion rate. Peak Pb and Zn concentrations can be related to the maximum influx from mining activity in the Tees catchment c. AD 1880 or to industrial activity within the Tees estuary during the 20th Century. The former provides rates of tidal sedimentation of approximately 1, 2, 3 and c. 10 mm yr^-1 for the upper saltmarsh, the lower saltmarsh, the mudflats and a tidal sandflat, respectively, whilst the latter gives corresponding accretion rates of 4, 10, 12 and c. 25 mm yr^-1.     

Possible effects when two deficient essential elements are applied simultaneously

With assumptions of a possitive response of a plant to essential element “A”; and positive response also obtained when essential element “B”; is added without any application of element “A”; (either in soil medium or medium without absolute absence of both elements further assumed), five different types of responses are postulated and plotted. Additive, antagonistic and synergistic effects are included.     

Tibial tuberosity advancement in 92 canine stifles: initial results,clinical outcome and owner evaluation

Objective To investigate the clinical outcomes, complications and owners' evaluation of the tibial tuberosity advancement (TTA) procedure in canine stifles. Methods A retrospective study of hospital records was performed to identify dogs diagnosed with partial or complete cranial cruciate ligament (CCL) rupture that had undergone TTA repair. Information obtained included signalment, period of lameness, surgical report, evidence of meniscal injury, postoperative recovery and peri-operative complications. Owners were asked to assess the long-term outcome. Results In a total of 72 dogs (median age, 6 years; median body weight, 34.8 kg), TTA was performed in 92 stifles. Twenty breeds were represented, with Labrador Retrievers and Rottweilers the most common. The period of lameness ranged from 3 days to 24 months. The median pre-operative lameness score was 3/4 and meniscal injury was present in 51 stifles. Minor complications occurred in 29% of cases. Major complications occurred in 6.5% of cases and consisted of meniscal injury and two tibial tuberosity fractures. All were successfully managed, with good limb function when subsequently assessed. In the owner evaluation, 96% reported moderate to great improvement postoperatively, with no lameness at rest and mild to no lameness after vigorous exercise. Conclusion Clinical outcome and owner evaluations in this case series indicate favourable results can be expected when CCL-deficient stifles are treated with TTA.     

Vascular distribution of contrast medium during intraosseous regional perfusion of the distal portion of the equine forelimb

OBJECTIVE: To describe the vascular distribution pattern of contrast medium during intraosseous regional perfusion (IORP) of the distal portion of the equine forelimb. SAMPLE POPULATION: 13 cadaveric forelimbs from 12 horses without forelimb diseases. PROCEDURES: Serial lateromedial radiographic views were taken of the distal portion of 10 heparinized cadaveric forelimbs at 0, 1, 2, 6, 15, and 30 minutes during IORP of the third metacarpal bone (MCIII) by use of iodinated contrast medium and a tourniquet placed over the proximal portion of MCIII. Vascular regions of interest (ROI) were created for each radiograph. Reviewers identified the presence or absence of contrast medium-induced opacified vessels in all ROI on radiographs. This information was summarized to identify vessel-filling patterns over time. Vessel identification was verified by use of computed tomography angiography and latex perfusion studies on the distal portion of separate cadaveric forelimbs. RESULTS: During IORP, contrast medium filled the medullary cavity of the MCIII; exited via transcortical vessels; and diffused distally to the remaining arteries and veins of the forelimb, distal to the tourniquet. Maximum vessel and soft tissue opacification occurred in most specimens at 6 and 30 minutes, respectively. Serial radiography vessel patterns matched those of computed tomography images and dissected specimens. CONCLUSIONS AND CLINICAL RELEVANCE: IORP provides a repeatable pattern of vascular distribution in the distal portion of the equine forelimb. To our knowledge, our study provides the first documentation of arterial perfusion by use of IORP; results of previous reports indicate that IORP delivers medications to only the venous vessels of the perfused forelimb.