A review of bovine Johne's disease control activities in 6 endemically infected countries

Mycobacterium avium subspecies paratuberculosis (MAP) is endemic in the bovine populations of many countries and can cause a significant reduction in animal welfare and production efficiency making control desirable. Effective control has proved very difficult to achieve despite multiple regionally coordinated programmes being in existence since the 1920s. The international community increasingly recognises the value in learning from the collective experiences of existing programmes to improve the effectiveness of control. The aim of this review is to outline key aspects of bovine Johne's disease control activities across 6 endemically infected countries to facilitate comparison of current international practice. The background, control activities and monitoring components of programmes in Australia, Canada, Denmark, the Netherlands, the United Kingdom and the United States of America were individually reviewed. Factual accuracy of each review was checked by individuals involved in the respective programmes before the reviews were condensed and combined into a single document presented here, with the complete reviews of each programme available as supplementary material. There was considerable heterogeneity in key aspects of control activity design including goals, responses to declining participation, herd classification, recommended control measures and associated test requirements. The data presented will be of interest to organisations that are involved in developing new or existing regionally coordinated BJD control activities

Monitoring the health and productivity of farmed ostrich flocks

The Australian farmed ostrich industry is in a state of T transition. Since reestablishment in this country after anabsence of about 60 years, the industry has expanded rapidly, both in numbers of producers and birds. Until recently, most flocks were small and individual birds were of considerable value. Accordingly, veterinary attention has focused on the health and productivity of individual birds. However, a program of sustainable commercial slaughtering has now been instigated, resulting in the slaughter of young mature birds to produce high quality leather and meat. The monetary value of individual birds has also dropped substantially in recent months. With these changes, the overall performance of the flock, rarher than individual birds, will become increasingly important. With the shifting emphasis towards flock performance, there will be an increasing need for veterinarians to monitor the health and productivity of farmed ostrich flocks. Monitoring programs have been developed for many livestock industries, including poultry (RJ Jenner, personal communication), to provide an ongoing assessment of the health and productivity of animal and bird populations. However, no published information is available about similar programs for ostrich flocks. This paper briefly reviews issues relating to the development of monitoring programs for ostrich populations, and presents a case study to demonstrate the potential uses of monitoring information for ostrich producers and their veterinarians

The performance of farmed ostrich hens in eastern Australia

A prospective observational epidemiological study was undertaken in the south-eastern region of Queensland in eastern Australia to collect accurate information on the performance of farmed ostriches, and to identify the most important constraints facing on-farm production. This paper (the first in a series of three) focuses upon aspects of the general study design and the productivity of ostrich hens on 12 farms in this region. These farms were a convenience sample and were visited regularly for at least 12 months from July 1993. Some general farm information was collected using a questionnaire; however, the focus of the study was mainly upon the performance of defined cohorts of hens (a cumulative total of 61 hens), eggs (910 eggs) and chicks (394 chicks). A number of methods was used to improve data quality. The study farms were managed by producers with a median of 2.5 years of active ostrich industry involvement, reflecting the recent establishment and rapid growth of the industry in this region. During the study period, 61 hens were observed for a period of 41.1 hen-years. Most hens were young (median age 2.7 years at the end of the observation period) and held in pairs. Egg production was poor, with the more-productive hens significantly older than those less-productive. Egg laying among the more-productive hens was clustered in time, with half of all eggs being laid within 2 days of a previous egg. Clutches of eggs were generally small (weighted mean 3.5 eggs) but were laid frequently (weighted mean 9.4 days between clutches). The farm and hen prevalences of Libyostrongylus douglassi infection were 33% and 40%, respectively.Triple D Ostrich FarmsThe University of QueenslandRural Industries Research and Development Corporatio

The performance of farmed ostrich eggs in eastern Australia

A prospective observational epidemiological study was undertaken in the south-eastern region of Queensland in eastern Australia to collect accurate information on the performance of farmed ostriches, and to identify the most important constraints facing on-farm production. This paper (the second in a series of three) focuses upon the performance of 910 ostrich eggs laid on 12 farms in this region between 1 July 1993 and 30 June 1994. Each egg was observed from lay until it hatched, was permanently removed from the incubator unhatched, or reached the 46th day of incubation without hatching (whichever occurred first). Eggs weighed on average 1301.9 g at lay, were stored for a mean of 3.7 days prior to the start of incubation, and lost an average of 15.5% of the initial set weight during the period of incubation. Overall fertility and hatchability percentages of 68.1% and 67.0%, respectively, were achieved. Laboratory examination was performed on some eggs that were infertile or failed to hatch. Although bacteria were isolated from some of these eggs, bacterial infection may not have been an important cause of incubation failure. Egg-level factors were examined for association with egg fertility and with egg hatchability using random-effects logistic regression modelling. There was no unconditional association between egg fertility and either egg weight at the start of incubation, the season of lay or the duration of egg storage prior to incubation. There was evidence, however, indicating a relationship between egg fertility and nonexamined pair and farm-level factors. Egg hatchability was conditionally associated with egg weight at the start of incubation, the percentage egg weight loss during incubation and the season of lay, and random pair-level extra-binomial variation was also demonstrated. The relationship between hatchability and weight loss was curvilinear; fertile eggs were most likely to hatch with weight loss during incubation of between 12 and 15% of the egg weight at the beginning of incubation

The performance of farmed ostrich chicks in eastern Australia

A prospective observational epidemiological study was undertaken in the south-eastern region of Queensland in eastern Australia to collect accurate information on the performance of farmed ostriches, and to identify the most important constraints facing on-farm production. This paper (the third in a series of three) focuses upon the performance of 394 chicks that hatched on 11 farms in this region from eggs laid between 1 July 1993 and 30 June 1994. Each chick was observed from hatch until dying, leaving the farm of origin or reaching 4 months of age (whichever occurred first). A total of 60.8% of the chicks survived to 4 months of age, with an overall crude mortality rate during the period of observation of 14.0 deaths per 100 chick-months at risk. The most common causes of death were the development of a lower-limb deformity (most frequently tibiotarsal rotation which accounted for 36% of all chick deaths), 'fading chick syndrome' (13%), and salmonellosis (11%). Only 83% of the chicks remained free of tibiotarsal rotation during the period of observation. This condition was generally first detected in chicks between 2 and 10 weeks after hatch, and the median survival time following diagnosis was 10 days. 'Fading chick syndrome' mainly affected chicks less than 3 weeks of age and did not appear to spread in a contagious manner. Chicks died following infection with Salmonella typhimurium on only one farm. Chick-level factors affecting survival during the 4 months following hatch were examined using the Cox proportional hazards regression model. After accounting for farm-level effects, risk factors for death or euthanasia during the first 4 months following hatch included the weight of the chick at hatch, and the development of tibiotarsal rotation. The need of the industry-wide development and adoption of objective measures of productivity is discussed, and some relevant measures are proposed

Livestock disease resilience: from individual to herd level

Infectious diseases are a major threat to the sustainable production of high-producing animals. Control efforts, such as vaccination or breeding approaches often target improvements to individual resilience to infections, i.e., they strengthen an animal’s ability to cope with infection, rather than preventing infection per se. There is increasing evidence for the contribution of non-clinical carriers (animals that become infected and are infectious but do not develop clinical signs) to the overall health and production of livestock populations for a wide range of infectious diseases. Therefore, we strongly advocate a shift of focus from increasing the disease resilience of individual animals to herd disease resilience as the appropriate target for sustainable disease control in livestock. Herd disease resilience not only captures the direct effects of vaccination or host genetics on the health and production performance of individuals but also the indirect effects on the environmental pathogen load that herd members are exposed to. For diseases primarily caused by infectious pathogens shed by herd members, these indirect effects on herd resilience are mediated both by individual susceptibility to infection and by characteristics (magnitude of infectiousness, duration of infectious period) that influence pathogen shedding from infected individuals. We review what is currently known about how vaccination and selective breeding affect herd disease resilience and its underlying components, and outline the changes required for improvement. To this purpose, we also seek to clarify and harmonise the terminology used in the different animal science disciplines to facilitate future collaborative approaches to infectious disease control in livestock

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): Batrachochytrium salamandrivorans (Bsal)

Non peer reviewe

Low atmospheric pressure system for stunning broiler chickens.

Non peer reviewe

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): Trypanosoma evansi infections (including Surra)

Non peer reviewe