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101.
Digital dermatitis is a worldwide disease causing lameness in cattle, especially when housed. Despite its widespread nature there are relatively few peer-reviewed articles providing experimental data concerning its treatment and control. At the risk of descending to anecdote, this review attempts to summarise the current state of knowledge. Three approaches to digital dermatitis treatment have been used: (1) systemic antibiotics, (2) individual topical treatment, and (3) mass topical therapy using a footbath. Systemic antibiotics have become a rare treatment because of their cost and perceived lack of efficacy. Individual topical treatment, mainly with antibiotic preparations, is the most commonly reported method. It is widely considered the treatment of choice by virtue of reliable information about efficacy, the advantage of precise targeting of antibiotic usage and the requirements of legislation. However, at least in the UK, mass treatment of digital dermatitis by foot bathing is commonly used on many farms. In some cases, for example with antibiotic footbath solutions, these treatments create legislative, health and safety and environmental difficulties. Despite the widespread use of many different treatments, there is a lack of good comparative data and the consequence is a very variable and somewhat anecdotal approach in the field. There is a pressing need for well-researched treatment strategies for different herd situations.  相似文献   
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Polioencephalomalacia was diagnosed histologically in cattle from two herds on the Darling Downs, Queensland, during July–August 2007. In the first incident, 8 of 20 18-month-old Aberdeen Angus steers died while grazing pastures comprising 60% Sisymbrium irio (London rocket) and 40% Capsella bursapastoris (shepherd's purse). In the second incident, 2 of 150 mixed-breed adult cattle died, and another was successfully treated with thiamine, while grazing a pasture comprising almost 100% Raphanus raphanistrum (wild radish). Affected cattle were either found dead or comatose or were seen apparently blind and head-pressing in some cases. For both incidents, plant and water assays were used to calculate the total dietary sulfur content in dry matter as 0.62% and 1.01% respectively, both exceeding the recommended 0.5% for cattle eating more than 40% forage. Blood and tissue assays for lead were negative in both cases. No access to thiaminase, concentrated sodium ion or extrinsic hydrogen sulfide sources were identified in either incident. Below-median late summer and autumn rainfall followed by above-median unseasonal winter rainfall promoted weed growth at the expense of wholesome pasture species before these incidents.  相似文献   
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Objective To investigate the therapeutic and prophylactic efficacy of an ivermectin controlled-release capsule against nasal bots (Oestrus ovis) in sheep.
Design Trial 1 – A pen study with controls. Trial 2 – A field study with controls.
Animals Trial 1 – Forty Merino wethers with natural infestations of nasal bot were used. Trial 2 – One hundred nasal bot-free wethers were used.
Procedure Trial 1 – Ten randomly selected animals were slaughtered and the heads split and examined to confirm bot infestation. Fifteen animals were allocated to untreated controls and 15 to treatment with a controlled-release capsule delivering ivermectin at ≥ 20 μg/kg/day for 100 days. Twenty-nine days after treatment the sheep were killed and examined for nasal bots. Trial 2 – Nasal bot-free sheep were allocated to two groups of 45 animals. One group was untreated the other sheep were treated with capsules as above. The sheep were grazed as a single group exposed to natural challenge from O ovis . Ninety days after treatment the animals were slaughtered and examined for nasal bot infestation.
Results Trial 1 – Live O ovis larvae were recovered from 60% of control sheep. No live larvae were collected from treated sheep. Trial 2 – Forty-one percent of untreated sheep harbored nasal bot infestations. No live larvae were collected from any treated animal.
Conclusion Treatment with a single ivermectin controlled-release capsule was 100% effective against existing infestations of O ovis and as a prophylactic treatment for this parasite.  相似文献   
105.
Objective The objective of this work was to perform a comprehensive phenotypic characterisation of 16 isolates of bacteria previously identified as Actinobacillus equuli.
Design The 16 isolates that had been obtained from Australian animals – 15 from horses and one from a rabbit – were compared with reference strains of A equuli, A capsulatus, Pasteurella caballi and Bisgaard Taxa 9 and 11.
Results The characterisation study demonstrated that only nine of the isolates were A equuli . The other isolates were identified as A capsulatus (the isolate from rabbit), P caballi (one isolate), Bisgaard Taxon 11 (two isolates) and Bisgaard Taxon 9 (one isolate). The final two isolates could not be assigned to any recognised species or taxa.
Conclusion This study has highlighted the importance of a complete characterisation of Actinobacillus -like organisms isolated from horses and rabbits. The study represents the first time that A capsulatus, P caballi and Bisgaard Taxa 9 and 11 have been recognised as being present in Australia.  相似文献   
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Peridotite xenoliths from the Cascade arc in the United States and in the Japan arc have neodymium and osmium isotopic compositions that are consistent with addition of 5 to 15 percent of subducted material to the present-day depleted mantle. These observations suggest that osmium can be partitioned into oxidized and chlorine-rich slab-derived fluids or melts. These results place new constraints on the behavior of osmium (and possibly other platinum group elements) during subduction of oceanic crust by showing that osmium can be transported into the mantle wedge.  相似文献   
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Parthenogenetic activation using zona‐free oocytes offers an alternative model that could be applied to develop protocols for the activation of reconstructed embryos for cloning. The aim of this study was to compare the efficacy of different methods for the activation of zona‐free buffalo oocytes in terms of their effects on the developmental competence of parthenogenetic embryos. The effects of zona removal on parthenogenetic activation and in vitro developmental competence of metaphase II oocytes were also examined. All activation methods were followed by incubation of 2 mm 6‐dimethylaminopurine (6‐DMAP) for 4 h. Out of three different pulse strengths (1.2, 2.1 or 3.3 kV/cm) used, 2.1 kV/cm resulted in the highest blastocyst rate (25.3%). On comparing different chemical agents and electric pulse, highest blastocyst rate was observed for calcium ionophore (CaI) (28.6%) followed by ethanol (25.0%), electric pulse (22.5%) and combined CaI and ethanol treatment (16.7%) although differences among them were not significant. Furthermore, a significantly reduced developmental potential was observed in zona‐free oocytes when compared to zona‐intact ones up to the blastocyst stage (44.3% vs 27.1%). In conclusion, zona‐free buffalo oocytes can be successfully activated for parthenogenetic development using chemical or electrical stimulation. Out of different agents examined, CaI followed by 6‐DMAP resulted in the highest blastocyst rate.  相似文献   
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