Skin disease affecting the conservation of the western swamp tortoise (Pseudemydura umbrina)

Objective To review the present position of the western swamp tortoise ( Pseudemydura umbrina ) as an endangered species and significant health issues affecting efforts to save it from extinction.
Procedure A retrospective analysis of the husbandry, hospital and pathology records of the western swamp tortoise captive breeding program at Perth Zoo.
Results In 1987 a captive breeding project was developed to prevent the extinction of the western swamp tortoise but an outbreak of a necrotising dermatitis in 1989 threatened the survival of the captive bred hatchlings. Less severe outbreaks occurred in 1990 and 1993, with isolated cases in between. Of 283 tortoises that were born in captivity or came into captivity from the wild, 37 (13.1%) were affected, comprising 37% of all males, 26% of all females and 13% of animals of unknown gender. Of the affected animals, 70% were less than 2 years of age and 29% were older. Males were 1.6 times more likely to be infected than females but this difference was not statistically significant (P = 0.27). Culture of the lesions consistently yielded unidentified Pseudomonas sp.
Conclusion Improved husbandry, such as strict maintenance of water quality and temperature conditions similar to that of the animal's natural habitat, and monitoring the health of individual tortoises have successfully controlled skin disease in the captive breeding of the western swamp tortoise.     

禽用活疫苗SPF化现状及对兽用生物制品企业的影响

目前,禽病防疫仍以疫苗免疫接种为主,疫苗安全性直接影响疫病防控效果,优质疫苗能预防疾病,提高家禽的生产性能,创造经济效益。相反,劣质疫苗可能对动物造成伤害,对环境造成污染,乃至威胁人类的健康。因此,选择安全高效的优质疫苗是做好家禽疫病防疫的关键。为保证疫苗质量安全,实行禽用活疫苗SPF化已经势在必行。     

Use of Vaginal Electrical Resistance to Diagnose Oestrus,Dioestrus and Early Pregnancy in Synchronized Tropically Adapted Beef Heifers

The primary objective of this study was to determine whether a single measurement of intravaginal electrical resistance (VER), using the commercially available Ovatec^® probe, can discriminate between dioestrus and oestrus in Bos indicus females, which had been treated to synchronize oestrus. Santa Gertrudis heifers (n = 226) received one of three oestrous synchronization treatments: double PGF_2α 10 days apart, 8‐day controlled internal drug release (CIDR) treatment or CIDR pre‐synchronization + PGF_2α 10 days after CIDR removal. The heifers were inseminated within 12 h following observed oestrus, or, if not observed, at a fixed time approximately 80 h, following the last synchronization treatment. They were palpated per rectum for signs of pregnancy 9 weeks after artificial insemination (AI). Vaginal electrical resistance measurements were taken at the completion of synchronization treatments (presumed dioestrus), immediately prior to AI (oestrus), and then at 3 and 9 weeks post‐AI. Mean VER differed between presumed dioestrus and oestrus (113.7 vs 87.4, p < 0.001). The area under the receiver operating characteristics (ROC) curve was 0.925, indicating that VER was highly discriminatory between dioestrus and oestrus. Vaginal electrical resistance at time of AI was negatively associated with odds of conception when all inseminations were included in the analyses [odds ratio (OR) = 0.97; 95% CI 0.95–1.00; p = 0.018], but not when fixed time AIs were excluded (OR = 1.00; 95% CI 0.97–1.03; p = 0.982). Mean VER readings differed between pregnant and non‐pregnant animals at both 3 weeks (120.5 vs 96.7, p < 0.001) and 9 weeks (124.0 vs 100.3, p < 0.001) post‐AI. However, 3‐ and 9‐week VER measurements were not highly discriminatory between pregnancy and non‐pregnancy (area under ROC curve = 0.791 and 0.736, respectively). Mean VER at time of AI for animals diagnosed in oestrus differed between each of the oestrous synchronization treatments (84.7, 73.6 and 78.9, groups 1–3 respectively, p < 0.001). These findings suggest that measurement of VER may improve accuracy of oestrus diagnoses when selecting cattle for AI following oestrous synchronization programmes involving tropically adapted cattle.     

Evidence that moxidectin is a greater risk factor than ivermectin in the development of resistance to macrocyclic lactones by Ostertagia spp in sheep in south eastern Australia

AIM: To determine associations between resistance of Ostertagia (= Teladorsagia) spp to macrocyclic lactone (ML) anthelmintics and history of use of anthelmintics, by type, on commercial sheep farms in temperate regions of southern South Australia and Victoria, Australia.

METHODS: Faecal egg count reduction tests (FECRTs) were conducted during a 2.5-year period (from August 2001 to January 2004) and records of the type of anthelmintic used in the 5 years preceding the FECRTs were collected from commercial sheep farms (n=103) in southern South Australia and Victoria, and data analysed retrospectively. ML resistance was defined as <95% reduction of Ostertagia spp 10–14 days after treatment with ivermectin (IVM), orally, at half the manufacturer's recommended dose rate. Use of anthelmintics in the preceding 5 and 10 years on each property was classified according to the nett number of years each of the following classes of drug had been used: IVM oral liquid (IVO), IVM controlled-release capsules (CRCs), abamectin (ABA), moxidectin (MOX) or a non-ML an- thelmintic. The prevalence of ML resistance, by property, was analysed for associations with prior use of anthelmintics.

RESULTS: Resistance by Ostertagia spp to ML anthelmintics was evident on 51/103 (49.5%) properties. The prevalence of resistance was lowest (23%) on properties on which MOX had not been used, and was significantly higher (64–77%) on properties on which MOX had been used for ≥2 of the preceding 5 years (p<0.001). In contrast, the prevalence of resistance was highest (70–74%) on the properties on which IVM, or IVM and/ or ABA, had not been used in the previous 5 years (on which the use of MOX was predominant), and was markedly lower (20– 42%) on properties that had used IVM or IVM and/or ABA for at least one of the preceding 5 years. Prevalence of resistance was higher for properties on which the only ML anthelmintic used was MOX (19/29=66%) than for those on which the only ML used was IVO (2/19=11%; p<0.001). Properties on which the only ML used was MOX were 2.72 times more likely to have resistance than properties on which the only ML used was IVO (95% confidence interval (CI) = 1.01–5.08).

CONCLUSION: Use of MOX for ≥2 of the preceding 5 years was associated with a higher prevalence of resistance to ML by Ostertagia spp on sheep farms in south eastern Australia than the use of IVO.     

Visualization of three-dimensional chaos

Most chaotic mixing experiments have been restricted to two-dimensional, time-periodic flows, and this has shaped advances in theory as well. A prototypical, bounded, three-dimensional flow with a moderate Reynolds number is presented; this system lends itself to detailed experimental observation and allows for high-precision computational inspection. The flow structure, captured by means of cuts with a laser sheet (experimental Poincare section), was visualized with the use of continuously injected fluorescent dye streams and revealed detailed chaotic structures with high-period islands.     

Management of a stingray barb laceration and suspect envenomation in a dog

This case report describes the successful management of a stingray laceration and suspected envenomation using a combination of opioid analgesia, heat compression, antimicrobial therapy, surgical debridement and closure. Stingray envenomation in the dog is a rare clinical presentation and is yet to be documented in the Australian veterinary literature. Envenomation can be markedly painful and may cause swelling and local tissue necrosis. No consensus on treatment guidelines has been published. Diagnostics and treatments performed are outlined with recommendations on a management plan for future cases.     

Use of Density Centrifugation for Delayed Cryopreservation of Stallion Sperm: Perform Sperm Selection Directly after Collection or after Storage?

Equipment for cryopreservation of stallion sperm is not always available. In such cases, diluted semen can be shipped to a facility for later cryopreservation. The aim of this study was to evaluate if selection of sperm via density centrifugation yields higher survival rates when cryopreservation is to be delayed (i.e. carried out after 1 day of storage at 5°C). Two‐layer iodixanol as well as single‐layer Androcoll density centrifugation were tested and compared with samples prepared with standard centrifugation. Special emphasis was placed on comparing centrifugation on the day of semen collection with centrifugation after 1‐day refrigerated storage. Sperm morphology and motility as well as membrane and chromatin integrity were evaluated before and after centrifugation. Sperm motility and membrane integrity were also assessed after cryopreservation. It was found that both two‐ and single‐layer density centrifugation processing resulted in higher percentages of morphologically normal and motile sperm with higher membrane and chromatin integrity, as compared to standard centrifugation or diluted samples. Differences were only in the order of magnitude of 5%. Recovery rates after density centrifugation were only approximately 30–40%. When cryopreservation was carried out after 1‐day refrigerated storage, centrifugation processing of sperm directly after semen collection resulted in higher percentages of plasma membrane intact sperm post‐thaw as compared to performing centrifugation processing of stored sperm just prior to cryopreservation. No significant differences in progressively motile sperm post‐thaw were seen. Taken together, for delayed cryopreservation, it is best to perform density centrifugation directly after collection rather than immediately prior to cryopreservation.     

A history of canine parvovirus in Australia: what can we learn?

Canine parvovirus (CPV) has been reported throughout the world since the late 1970s. Published information was reviewed to draw insights into the epidemiology, pathogenesis, diagnosis, treatment and outcomes of CPV disease in Australia and the role of scientific research on CPV occurrence, with key research discoveries and knowledge gaps identified. Australian researchers contributed substantially to early findings, including the first reported cases of parvoviral myocarditis, investigations into disease aetiopathogenesis, host and environmental risk factors and links between CPV and feline panleukopenia. Two of the world's first CPV serological surveys were conducted in Australia and a 1980 national veterinary survey of Australian and New Zealand dogs revealed 6824 suspected CPV cases and 1058 deaths. In 2010, an Australian national disease surveillance system was launched; 4940 CPV cases were reported between 2009 and 2014, although underreporting was likely. A 2017 study estimated national incidence to be 4.12 cases per 1000 dogs, and an annual case load of 20,110 based on 4219 CPV case reports in a survey of all Australian veterinary clinics, with a 23.5% response rate. CPV disease risk factors identified included socioeconomic disadvantage, geographical location (rural/remote), season (summer) and rainfall (recent rain and longer dry periods both increasing risk). Age <16 weeks was identified as a risk factor for vaccination failure. Important knowledge gaps exist regarding national canine and feline demographic and CPV case data, vaccination coverage and population immunity, CPV transmission between owned dogs and other carnivore populations in Australia and the most effective methods to control epizootics.