Longitudinal study of OJD and the effects of whole flock vaccination with Gudair : whole flock OJD vaccination at Merrill.

Ovine paratuberculosis or Johne’s disease is an insidious mycobacterial infection of sheep capable of causing wasting and death. It has emerged in recent years in Australia as a cause of significant losses in some infected sheep flocks. MLA Project OJD.015 was commenced to enable a detailed longitudinal case study of an attempt to control the disease in a large self-replacing Merino flock at Gunning in NSW with an owner-estimated annual mortality rate up to 25%. Vaccination of the whole flock with exception of a small group in each age cohort was conducted, with documentation of the effects of vaccination and other strategies on mortalities and mycobacterial faecal excretion rates and mortalities in all age groups of animals. The study concluded that the significant decline in mortality risk from 24.2% to 2.85 during the study may only be partially attributed to the increased flock immunity following vaccination. By accompanying vaccination with extensive changes in flock management, including culling of clinical cases, sale of ‘at risk’ stock and introducing of replacements and reduction in stocking rates, control of the losses can be rapidly achieved in an infected flock with a high prevalence of OJD. This project has enhanced the knowledge and understanding of the performance of this vaccine under Australian conditions in a high OJD prevalence environment and recommends that field evaluation of the performance of the vaccine continue, particularly in low challenge environments

Longitudinal study of OJD and the effects of whole flock vaccination with Gudair : whole flock OJD vaccination at Merrill.

Ovine paratuberculosis or Johne’s disease is an insidious mycobacterial infection of sheep capable of causing wasting and death. It has emerged in recent years in Australia as a cause of significant losses in some infected sheep flocks. MLA Project OJD.015 was commenced to enable a detailed longitudinal case study of an attempt to control the disease in a large self-replacing Merino flock at Gunning in NSW with an owner-estimated annual mortality rate up to 25%. Vaccination of the whole flock with exception of a small group in each age cohort was conducted, with documentation of the effects of vaccination and other strategies on mortalities and mycobacterial faecal excretion rates and mortalities in all age groups of animals. The study concluded that the significant decline in mortality risk from 24.2% to 2.85 during the study may only be partially attributed to the increased flock immunity following vaccination. By accompanying vaccination with extensive changes in flock management, including culling of clinical cases, sale of ‘at risk’ stock and introducing of replacements and reduction in stocking rates, control of the losses can be rapidly achieved in an infected flock with a high prevalence of OJD. This project has enhanced the knowledge and understanding of the performance of this vaccine under Australian conditions in a high OJD prevalence environment and recommends that field evaluation of the performance of the vaccine continue, particularly in low challenge environments

Deriving prevalence estimates of depressive symptoms throughout middle and old age in those living in the community

BACKGROUND: There is considerable debate about the prevalence of depression in old age. Epidemiological surveys and clinical studies indicate mixed evidence for the association between depression and increasing age. We examined the prevalence of probable depression in the middle aged to the oldest old in a project designed specifically to investigate the aging process. METHODS: Community-living participants were drawn from several Australian longitudinal studies of aging that contributed to the Dynamic Analyses to Optimise Ageing (DYNOPTA) project. Different depression scales from the contributing studies were harmonized to create a binary variable that reflected "probable depression" based on existing cut-points for each harmonized scale. Weighted prevalence was benchmarked to the Australian population which could be compared with findings from the 1997 and 2007 National Surveys of Mental Health and Well-Being (NSMHWB). RESULTS: In the DYNOPTA project, females were more likely to report probable depression. This was consistent across age levels. Both NSMHWB surveys and DYNOPTA did not report a decline in the likelihood of reporting probable depression for the oldest old in comparison with mid-life. CONCLUSIONS: Inconsistency in the reports of late-life depression prevalence in previous epidemiological studies may be explained by either the exclusion and/or limited sampling of the oldest old. DYNOPTA addresses these limitations and the results indicated no change in the likelihood of reporting depression with increasing age. Further research should extend these findings to examine within-person change in a longitudinal context and control for health covariates.NHMRC (National Health and Medical Research Council of Australia

Study of the biological and economic impact of OJD in affected sheep flocks in NSW : 12 farm mortality study.

This study provides industry with factual information about the impact of OJD on farms in southern Australia. This is needed to assess the magnitude of the OJD problem and to direct control and management programs. On 12 farms, the average annual OJD mortality rate based on inventory records from 2002-2004 was 6.8% (range 1.8% to 17.5%), well above the accepted annual mortality rate (from all causes) for Australian sheep flocks. OJD losses accounted on average for 70% (range 17% to 100%) of the estimated total financial loss associated with sheep deaths in 2002. In addition this project confirmed that prevalence based on pooled faecal culture (PFC) could be used as an indicator of OJD mortality level and provided support for further investigation of several risk factors in a larger future study (MLA OJD.038). The gross margin model developed provides estimates of on-farm cost of OJD and of vaccination control for wool and sheep-meat enterprises including break-even points for vaccination at various prevalence levels. We recommend that producers, through industry extension activities, be informed of the substantial losses associated with OJD and be encouraged to apply the model to support decision making regarding OJD control

Studies on neurological disorders of neonatal calves associated with spongy changes in the central nervous system : neuroaxial oedema and the inborn errors of amino acid metabolism

Investigations of neurological disease in neonatal calves were conducted over a four and a half year period. The studies commenced with so called Hereditary Neuraxial Oedema of Poll Hereford calves. It was determined that two distinct disease entities in this breed had led to confusion regarding the diagnosis of this disorder

The Food Security Challenge for the Buffalo Meat Industry: Perspectives from Lao PDR

The Asiatic swamp buffalo (Bubalus bubalis) is an important livestock species in the Lao People's Democratic Republic (Laos), with smallholder farmers owning the majority of an estimated 774,200 buffalo. Of the estimated 226,400 farm households with buffalo, 78% have a herd size of four or fewer, kept as a storage of wealth, sale for beef, for manure as fertilizer, and decreasingly, draught power. The total meat consumption in Laos and China was approximately 21 kg and 58 kg per capita in 2009, with an annual growth rate forecast of 4.5% and 3.1%. Increasing demand for meat in both domestic and neighboring markets offers opportunities for smallholders to gain more income from their livestock, particularly buffalo. However improving buffalo production requires numerous management constraints to be addressed, including: health issues (parasites and endemic diseases, particularly Toxocara vitulorum and Haemorrhagic Septicaemia control), biosecurity and transboundary disease (Foot and Mouth Disease control), nutritional deficits, low reproductive performance, high slaughter rates of pregnant cows, undeveloped trade and marketing systems, limited veterinary and extension service capacity, and potentially climate change and policy impacts. This paper reviews available information on these constraints to identify remaining gaps in knowledge and offer potentially suitable strategic interventions aimed at increasing the supply of buffalo in Laos. With the current rapid rate of economic development expected to continue in Laos and the Greater Mekong Subregion, expansion of the domestic and regional markets for food requires a more biosecure and sustainable supply of safe meat. Improving livestock health, productivity, processing and marketing, particularly of buffalo, is critical to ensuring poor smallholder communities can participate in and access these growing markets, providing improved rural livelihoods, poverty reduction and increased food security

Virus-induced congenital malformations in cattle

Diagnosing the cause of bovine congenital malformations (BCMs) is challenging for bovine veterinary practitioners and laboratory diagnosticians as many known as well as a large number of not-yet reported syndromes exist. Foetal infection with certain viruses, including bovine virus diarrhea virus (BVDV), Schmallenberg virus (SBV), blue tongue virus (BTV), Akabane virus (AKAV), or Aino virus (AV), is associated with a range of congenital malformations. It is tempting for veterinary practitioners to diagnose such infections based only on the morphology of the defective offspring. However, diagnosing a virus as a cause of BCMs usually requires laboratory examination and even in such cases, interpretation of findings may be challenging due to lack of experience regarding genetic defects causing similar lesions, even in cases where virus or congenital antibodies are present. Intrauterine infection of the foetus during the susceptible periods of development, i.e. around gestation days 60–180, by BVDV, SBV, BTV, AKAV and AV may cause malformations in the central nervous system, especially in the brain. Brain lesions typically consist of hydranencephaly, porencephaly, hydrocephalus and cerebellar hypoplasia, which in case of SBV, AKAV and AV infections may be associated by malformation of the axial and appendicular skeleton, e.g. arthrogryposis multiplex congenita. Doming of the calvarium is present in some, but not all, cases. None of these lesions are pathognomonic so diagnosing a viral cause based on gross lesions is uncertain. Several genetic defects share morphology with virus induced congenital malformations, so expert advice should be sought when BCMs are encountered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13028-015-0145-8) contains supplementary material, which is available to authorized users

Comparison of pre- and post-vaccination ovine Johne's disease prevalence using a Bayesian approach

postprintThis study was conducted to evaluate the effectiveness of GudairTM vaccine in decreasing the prevalence of shedding of Mycobacterium avium subsp. paratuberculosis (MAP) in flocks of varying initial prevalence. Thirty seven self-replacing Merino flocks from New South Wales and Victoria (Australia) that had been vaccinating lambs with GudairTM for at least five years were enrolled in the study. These flocks had been tested prior to or at commencement of vaccination using pooled faecal culture, agar gel immunodiffusion or both tests. These pre-vaccination test results were used to estimate pre-vaccination prevalence. Post-vaccination prevalence was estimated from culture of usually 7 pools of 50 sheep collected from the enrolled flocks in 2008-2009, approximately five or more years after commencement of vaccination. A Bayesian model was developed to estimate and compare the pre- and post-vaccination prevalences for the enrolled flocks. Apparent pre- and post-vaccination prevalences for flocks were modelled as functions of the true pre- and post-vaccination prevalences, respectively, and the sensitivities and specificities of the respective diagnostic tests. Logit-normal models were specified on pre- and post-vaccination true prevalences and were then used to make inferences about the median and 90th percentile of the prevalence distributions and their differences. Priors were mostly specified based on published literature or analysis of abattoir surveillance data for this population of flocks. The analysis found a significant decline in ovine Johne’s disease prevalence from a pre-vaccination median prevalence of 2.72% [95% probability interval (PI): 1.40; 6.86%] to a post-vaccination median prevalence of 0.72% (0.39; 1.27%). However 30 of the 37 flocks still contained sheep that were shedding MAP in their faeces. The results suggest that vaccination with Gudair™ is usually effective in reducing the prevalence of faecal shedding but the response to vaccination is variable among flocks. This approach could be implemented in similar situations to compare prevalences where information from multiple diagnostic tests with varied sensitivities and specificities is available. Keywords: Ovine Johne’s disease; Gudair; Vaccination; Abattoir surveillance; Faecal culture; Agar gel immune-diffusion test

Comparison of pre- and post-vaccination ovine Johne's disease prevalence using a Bayesian approach

This study was conducted to evaluate the effectiveness of GudairTM vaccine in decreasing the prevalence of shedding of Mycobacterium avium subsp. paratuberculosis (MAP) in flocks of varying initial prevalence. Thirty seven self-replacing Merino flocks from New South Wales and Victoria (Australia) that had been vaccinating lambs with GudairTM for at least five years were enrolled in the study. These flocks had been tested prior to or at commencement of vaccination using pooled faecal culture, agar gel immunodiffusion or both tests. These pre-vaccination test results were used to estimate pre-vaccination prevalence. Post-vaccination prevalence was estimated from culture of usually 7 pools of 50 sheep collected from the enrolled flocks in 2008-2009, approximately five or more years after commencement of vaccination. A Bayesian model was developed to estimate and compare the pre- and post-vaccination prevalences for the enrolled flocks. Apparent pre- and post-vaccination prevalences for flocks were modelled as functions of the true pre- and post-vaccination prevalences, respectively, and the sensitivities and specificities of the respective diagnostic tests. Logit-normal models were specified on pre- and post-vaccination true prevalences and were then used to make inferences about the median and 90th percentile of the prevalence distributions and their differences. Priors were mostly specified based on published literature or analysis of abattoir surveillance data for this population of flocks. The analysis found a significant decline in ovine Johne’s disease prevalence from a pre-vaccination median prevalence of 2.72% [95% probability interval (PI): 1.40; 6.86%] to a post-vaccination median prevalence of 0.72% (0.39; 1.27%). However 30 of the 37 flocks still contained sheep that were shedding MAP in their faeces. The results suggest that vaccination with Gudair™ is usually effective in reducing the prevalence of faecal shedding but the response to vaccination is variable among flocks. This approach could be implemented in similar situations to compare prevalences where information from multiple diagnostic tests with varied sensitivities and specificities is available. Keywords: Ovine Johne’s disease; Gudair; Vaccination; Abattoir surveillance; Faecal culture; Agar gel immune-diffusion test

Urban gulls adapt foraging schedule to human-activity patterns

Numerous animals are able to adapt to temporal patterns in natural food availability, but whether species living in relatively novel environments such as cities can adapt to anthropogenic activity cycles is less well understood. We aimed to assess the extent to which urban gulls have adapted their foraging schedule to anthropogenic food source fluctuations related to human activity by combining field observations at three distinct urban feeding grounds (park, school and waste centre) with global positioning system (GPS) tracking data of gulls visiting similar types of feeding grounds throughout the same city. We found that the birds' foraging patterns closely matched the timing of school breaks and the opening and closing times of the waste centre, but gull activity in the park appeared to correspond to the availability of natural food sources. Overall, this suggests that gulls may have the behavioural flexibility to adapt their foraging behaviour to human time schedules when beneficial and that this trait could potentially enable them to thrive in cities