Johne’s disease and Biosecurity for the Queensland Dairy Industry

Frequently Asked Questions

14 September 2017

The Department of Agriculture and Fisheries Biosecurity has put together this collection of frequently asked questions about Johne’s disease and the Queensland dairy industry.

What is Johne’s disease?

Johne’s (pronounced “Yo-nees”) is an infectious bacteria. It’s a serious wasting disease that affects cattle and other ruminants and primarily affects the intestinal tract.

Johne’s disease (JD) bacteria affect animals by causing a thickening of the intestinal wall resulting in a reduction in the absorption of food. The infected animal is hungry and eats, but cannot absorb any nutrients. This results in wasting and finally death. Diarrhoea and bottle jaw are also common signs in cattle.

A feature of JD is the slow growth of the bacteria. It can take many years from first infection to when these signs occur.

Progression of disease and excretion is accelerated by stress. The imbalance between nutrient intake and output in high-producing dairy cattle typically causes stress-induced JD in the second, third and fourth lactations.

How is JD spread between cattle?

Infected animals excrete bacteria in their faeces (manure), to contaminate the environment, pasture and water courses. This excretion begins well before clinical disease of wasting and scouring is apparent, but becomes much greater as disease progresses. In the final stages of disease, very high doses of infective bacteria are excreted into the environment.

Due to the slow growth of the bacteria and slow immune response, significant excretion by dairy cattle does not usually start until after two years of age. (Infected calves may also excrete bacteria early in the course of infection, but this appears to be of less importance for spread than the excretion by adults.)

Cattle which graze contaminated pasture or feed, or drink contaminated water, may ingest enough bacteria for the bacteria to cross from the gut into the tissues and establish infection.

Calves are much more susceptible than adult cattle to JD. The gut of calves can absorb nutrients, including the cow’s immunities in colostrum, more easily than older cattle. In general, cattle which are older than 12 months are unlikely to become infected, unless they are exposed to high levels of contamination.

For dairy cattle, a significant route of transmission from cow to calf is by soiling of udder and teats by the diarrhoea of JD and subsequent suckling from those soiled teats and ingestion of contaminated faeces.

Infection of the calf when it is still in-utero, or by milk being infected within the udder, is possible during late stages of infection and disease, but is probably not as frequent as ingestion by calves after birth.

What is the 3-Step Calf plan?

The 3-Step Calf Plan limits contact between calves and adult cattle and manure. This separation addresses the greatest risk of spread of JD within a herd, which is to calves getting infection from their infected dams or from the environment contaminated by other infected adults.

This 3-Step Calf Plan is central to the Dairy Australia recommendations for managing JD risk. Most dairy companies’ on-farm quality assurance programs will already specify the 3-Step Calf Plan.

The 3-Step Calf Plan is very relevant for herds which have a high prevalence or risk of JD. It is less relevant for herds with less JD risk, but still has application for controlling some other calf conditions such as calf scours and for minimising JD spread should it be present but just not yet detected.

The national standard for the 3-Step Calf Plan is:

  1. Calves to be taken off the cow within 12 hours of birth
  2. Ensure that no effluent from animals of susceptible species comes into contact with calves in the calf rearing area
  3. Calves up to 12 months old should be reared on pastures that, during the past 12 months, have not had adult stock or stock that are known to carry BJD.

There is scope for varying from the national standard, such as extending the cow-calf separation period to 24 hours or longer or rotating replacement heifer paddocks, but such variation must be clearly justified and described in the biosecurity plan. Due to the historically low prevalence of JD in the Queensland dairy industry, herd assurance testing with a negative result could support such a variation.

How is JD spread between properties?

JD is almost always spread onto a new dairy property by the conscious movement of cattle which are actually infected but not known to be infected

Theoretically, JD can be spread from neighbouring and up-stream properties by the movement of stray animals or in effluent or water. However, in Queensland where the prevalence of JD has been low for many decades, the probability of spread by stray animals or water is very low. This assessment may change over years if JD is allowed to spread into and within the State.

In general, JD is usually introduced in cattle walking out of a truck and up a race.

What testing can be done for JD?

JD testing can effectively assess the risk of infection at the herd level; it is less reliable for assessing individual live animals.

For many years, testing for JD has been criticised as ‘inaccurate’, but that criticism is simplistic and misleading. In fact, the laboratory procedures are very sound.

The common tests for JD in live animals are:

  • ELISA testing of blood samples to detect antibodies (part of the body’s immune response to the presence of foreign material)
  • Testing of faecal (manure) samples to detect excretion of the bacteria by either:
    • culture (trying to grow the bacteria under ideal laboratory conditions)
    • PCR (looking for specific fragments of DNA from the bacteria)

All of these live animal tests are limited by the slow growth of the bacteria or delayed immune response. Infected cattle which are in only the early stages of infection may not yet be excreting sufficient bacteria in faeces and may not yet have made sufficient antibodies to be detectable. Therefore a negative test result for an individual live animal cannot be interpreted as proving that the animal is not infected. At best, a negative individual live animal’s test result can show that it is not excreting bacteria at that point in time.

If a significantly large number of animals are tested with all results being negative, this provides good evidence that infection is not present on the property and thus animals sourced from the property are unlikely to be infected. Conversely, if testing detects infection in any animals, then the property and all animals on it must be considered at risk of being infected.

For cattle, there are three levels of sampling a ‘significantly large number of animals’:

  • Sample Test of 210 – 300 (depending on herd size) adult cattle that are representative of the whole herd
  • Check Test of 50 adult cattle that are representative of the whole herd
  • (Dairy herds only) Herd Environmental culture (HEC) Test of a single sample of fresh slurry taken from the milking yard.

The HEC test is the dairy industry standard test for herd assurance.

The ELISA blood test occasionally gives a positive result for animals which may later be shown to be uninfected. An investigation to distinguish a positive result as false rather than true typically takes 6 months and costs $1,000.

Although “false positives” are rare, they occur frequently enough, especially in coastal and northern Queensland, that faecal testing is probably preferable to blood testing despite the higher initial cost.

Can I just test a bull or replacement heifer before bringing it into my herd?

A test on an individual animal, especially at a low age (less than 2 years old), is a poor way of assessing its risk.

The slow growth of the bacteria, delayed immune response, and slow progression of disease mean that testing is likely to give negative results for infected animals until later in life.

At the time when infected animals are detectable by an individual test, they are likely to have progressed disease and already been spreading infection.

The only recommended way of assessing the risk of JD in a bull or replacement heifer before bringing it into a herd is to assess the risk of the property or properties on which it was born and spent its first 12 months. The Dairy

What is ‘Dairy Score’?

Dairy Score is a simplified tool for assessing JD risk in dairy cattle; it provides an acceptable standardised method of describing risk management.

A Dairy Score of 7 or 8 indicates that the property is actively managing to prevent infection entering or being spread from the property.

A score of between 2 and 6 indicates that the property’s focus for JD management is to minimise the impact of clinical disease, with higher scores indicating successful progression since the last clinical case. A score of 0 or 1 indicates that no management of JD risk is being undertaken at all.

Note that a Dairy Score is not an indicator of management skills, competence or even quality. A low score indicates infection but does not necessarily mean that producers are negligent or irresponsible. Some properties will best meet their production, trading and economic objectives by holding a low or zero score; others may prefer a higher score.

Why has Dairy Score been developed?

Johne’s disease management is now an industry program, developed by the national cattle industries (dairy and beef). The national industry program does not support regulatory controls by governments – this includes zoning, interstate movement restrictions, quarantines, regulatory tracing and regulatory testing.

The national industry program is based on voluntary, market-driven participation. Producers can decide how they manage JD risks according to their own property management objectives and market demands.

The program has developed tools to assist producers to assess and declare JD risks in line with voluntary producer management. These tools include:

  • Cattle Health Declaration
  • Dairy Score
  • J-BAS (similar to Dairy Score, for beef cattle)
  • JD Checklist of key elements to consider in planning
  • Biosecurity plan templates
What is a farm biosecurity plan?

A farm biosecurity plan identifies the risks to a property from the entry and spread of pests and diseases, and a set of measures designed to protect against those risks. Biosecurity risks include:

  • Animal diseases
  • Plant diseases
  • Pest animals
  • Weeds
  • Chemical contamination

There are many template options available:

  • QDO (interim)
  • Dairy Australia (soon)
  • LBN
  • Farm biosecurity website: www.farmbiosecurity.com.au
  • Australian Cattle Vets (through your local cattle veterinarian)

You do not have to use any particular template, just as long as key elements are considered.

The QDO interim template is designed to be simple and focussed on animal diseases, with capacity to include other biosecurity risks either now or in future reviews of the plan.

When it becomes available, the Dairy Australia template will be easier and more comprehensive, so will supplant the QDO one.

A farm biosecurity plan should be simple. Most importantly, it should be useful. It should help you to identify, prioritise and then implement biosecurity practices relevant to your property.

List the actions that:

  • You do already and will continue
  • You need to do (in a specified timeframe) within the next 12 months
  • Are aspirational, that you would like to do over a longer period.
How is LPA accreditation involved?

LPA accredited producers must have a Farm Biosecurity Plan and implement biosecurity practices in their on-farm management from 1 October 2017.

In effect, this applies to all producers who market livestock because LPA accreditation is necessary to access the National Vendor Declaration.

Biosecurity practices will be audited as part of the LPA audit.  However, to avoid duplication audits of dairy processor on-farm QA programs that include biosecurity practices should be accepted by LPA.

LPA is the Australian livestock industry’s on-farm assurance program.  It provides customers and consumers with an assurance that Australian red meat is produced ethically, safely and in a biosecure way.

How do farm biosecurity plans connect with on-farm dairy QA programs?

All dairy producers are required under their processor QA measures to implement an on-farm QA program.

The on-farm QA programs already address some key biosecurity risks such as mastitis and chemical contamination of milk, and animal welfare.

There is no need to duplicate biosecurity measures which are already effectively spelt out in the on-farm QA; the biosecurity plan can simply refer to those measures in the QA program.

What evidence supports the low-prevalence assessment for Queensland dairy industry?

Under a national program until 30 June 2016, the Queensland government provided regulatory protection against spread of JD into and within the state. The measures included certification and minimum standards of tested assurance for entry from other states, investigations of all suspected infection including clinical cases and traces, and movement restrictions on all animals which were confirmed or suspected of being infected.

The national program recognised higher prevalences of JD in the dairy industries of the southeastern states and the northern coastal area of NSW.

To support the regulatory approach, blood-test surveys were conducted on selected dairy herds in 1997 and 2007. Fifty animals in 50 herds were tested in each survey; no evidence of JD was detected.

The investigations conducted under the regulatory program including clinical cases and traces consistently found, until 2015, occasional entry of infection in cattle from interstate but no infection in Queensland-bred dairy cattle. Since 2015, there have been several detections of infection in Queensland-bred dairy cattle.

This showed that some cattle from interstate were bringing in JD and some of that may be slipping through the tracing net and establishing infection in dairy herds but at a level that was undetectable to that point. In contrast, other dairying areas of Australia and overseas see regular clinical cases and easily detectable infection.

The conclusion is that the Queensland dairy industry currently includes a small number of properties with JD, but the prevalence of infected herds, and the prevalence of infected animals within those herds, appears to be significantly lower than interstate.

What key JD elements should be in a farm biosecurity plan?

For most Queensland dairy properties that wish to prevent the entry of JD, the key elements of a biosecurity plan for JD will be:

  1. Secure boundaries
  2. Equivalent Dairy Scores, declared on a Cattle Health Declaration and supported by evidence, for all livestock entering the property. This is particularly important for dairy livestock sourced from areas of higher prevalence (southeastern Australia and northern coastal NSW). You should be careful that the Declaration refers to the property where the cattle were born and spent their first 12 months, rather than a more recent property.
  3. Assess the Cattle Health Declaration before bidding or buying cattle. To enable this, you should seek a copy from the vendor or selling agent well before the sale; do not allow yourself to be bullied into not getting the declaration. You may also wish to ask to see supporting evidence, such as the property biosecurity plan and/or test results, and lifetime NLIS property history of declared animals.
  4. The prior history of livestock introductions to your property should be reviewed, to identify and appropriately monitor high risks.
  5. The 3-Step Calf Plan should be practiced to minimise the risk of cattle becoming exposed and infected with JD as calves, when they are most susceptible, irrespective of Dairy Score.
  6. A Herd Environmental Culture (HEC) test on slurry from the dairy yard, conducted every two years, with the first round of testing completed by 30 June 2018.
What are the Dairy Score options for Queensland herds?

There is a transitional arrangement for dairy herds in Queensland to claim a Dairy Score of 8, but that will cease on 30 June 2018.

Note that the Queensland default Dairy Score of 8 does not apply to those properties which:

  • Were under quarantine for JD immediately before 1 July 2016, and
  • Have had clinical disease (wasting and scouring due to JD) in the preceding 5 years.

In the future Queensland dairy herds can either:

  • Continue to protect themselves from JD at Dairy Score 7 or 8, with responsible biosecurity management and biennial HEC testing
    • The differences between 7 and 8 are that at score 7 the biosecurity standards are self-managed but at score 8 the biosecurity plan is written and implemented with veterinary supervision including an annual veterinary review; and at score 8 routine cattle entries are limited to other score 8 cattle whereas score 7 herds can introduce cattle of score 7 or 8.
  • Do nothing and sit at score 0 or 1
    • The difference between 0 and 1 is that at score 0 nothing is being done to recognise or manage JD but at score 1 there has at least been an investigation that has detected JD.
    • As LPA requires at least a biosecurity plan for each property, dairy farmers are unlikely to be able to sit at score 0 or 1.
  • Have a biosecurity plan which recognises and manages JD including the 3-step calf plan, but not undertake HEC testing, at score 3 or 4
    • The difference between 3 and 4 is (unless there has been a clinical case in the previous 5 years) that score 4 requires the 3-step calf plan to have been in place for at least 4 years.

Dairy Score 8

Until 30 June 2018, Queensland herds may retain a Dairy Score of 8 by:

  • Having in place a property biosecurity plan which:
    • Addresses the elements of the JD checklist (livestock introductions, boundary security, monitoring, response to disease, carcasses, effluent and waste – details available on the Animal Health Australia website)
    • Addresses the elements of 3-Step Calf Plan (separation from cow, calf rearing area free of manure from adult animals, heifer and bull calf rearing paddocks not shared with adult cattle – details available on the Dairy Australia website)
    • Includes an annual veterinary review that covers a health check, calf hygiene and introductions
    • Is endorsed by a veterinary advisor, and
  • Undergo biennial Herd Environmental Culture (HEC) testing with negative results, and the first round of the testing must be completed prior to 30 June 2018.

Dairy Score 7

Queensland herds (other than ‘ineligible properties’) which have in place a biosecurity plan that does not include an annual veterinary review or is not endorsed by a veterinary advisor are eligible for a Dairy Score of 7. The biosecurity plan must address the JD Checklist and 3-step calf management. Note that LPA will require a biosecurity plan for accreditation from 1 October 2017.

A biennial HEC test is required to retain a Dairy Score of 7.

Dairy Score 3 or 4

Queensland herds (other than ‘ineligible properties’) which do have in place a biosecurity plan that includes the 3-step calf management, but do not undertake the biennial HEC test, are eligible for a Dairy Score of 3 (or Dairy Score of 4 if calf management has been implemented for at least 4 years).

Dairy Score 0

Any Queensland herd which does not have in place a biosecurity plan lapses to a Dairy Score of 0, or to 1 if clinical disease has been diagnosed as JD in the previous 3 years.

Due to LPA requirements for a biosecurity plan from 1 October 2017, these scores are not realistic options.

Ineligible properties

The Dairy Score of ‘Ineligible properties’ (unresolved infection or suspicion of infection on 30 June 2016, or clinical disease since then) is determined by whether there is a JD biosecurity plan, the duration since the last clinical case, the duration of 3-step calf management, culling of high-risk animals, and testing.

Refer to the Revised Dairy Score on the Dairy Australia website for further details.

What do commercial (non-stud) producers need to do?

JD management for Queensland commercial producers will be largely a balance between keeping their herds closed (to prevent the entry of infection) and introducing livestock (milkers, heifers, bulls) to sustain production. (There are some other elements to managing JD, such as keeping sound boundary fences, having a biosecurity plan, and testing.)

Think about who buys your products (milk and cattle) in the recent past and in the foreseeable future, and what level of assurance against Johne’s disease your market will demand. You may wish to consult your processor, buyers or agent for their views.

Think also about how much you want to protect your property and herd against becoming infected with Johne’s disease.

These two factors (protection from getting infected, market preference) will guide you towards your preferred Dairy Score.

How do I set up a biosecurity plan for a property which comprises multiple blocks, or for which there are mixtures of agistment and home herds?

Biosecurity plans for JD should be based on ‘herds’ according to risk of spread of infection. Cattle on different blocks within an enterprise, or agistment cattle on a property, may or may not be considered part of a single ‘herd’ depending on the level of co-grazing, animal exchange, and use of shared facilities.

A simple guide should be to only amalgamate cattle into one biosecurity plan if they contact each other or each other’s grazing land at all within a twelve months period, and to only separate cattle into more than one plan if they have no contact with each other or each other’s grazing land for at least 12 months.

A JD-trained veterinary advisor should definitely be engaged to develop a complex plan where more than one ‘herd’ might be involved in an enterprise.

Heifer agistment biosecurity options?

The new arrangements provide flexibility for all parties to manage biosecurity to best meet your needs.

The risk of excretion and thus spread of JD from agisted heifers may be considered as low (but not zero), even if infected, due to their young age. But, that young age also makes them more susceptible than adults to becoming infected if exposed.

The simplest plan is for all parties (agistor and agistee properties) to agree to maintain a common standard and Dairy Score.

Subject to a detailed risk assessment by a veterinary advisor, it may be possible to co-graze heifers of different Dairy Scores.

The paddocks which the heifers graze should not have been grazed in the preceding 12 months by adult cattle, and certainly not by adult cattle of a lower Dairy Score.

Properties which provide agistment for dairy heifers may not be able to test to support a Dairy Score because the heifers are too young. Such properties may be able to claim a Dairy Score based on the lowest score of the heifers, if the heifers don’t graze land used by adult stock, but using a veterinary advisor to support such an assessment is recommended.

Beef and dairy herds on the same property

There are no hard rules about whether a property with both dairy and beef herds should have a single biosecurity plan for the whole property or separate plans for each herd.

The biosecurity planning and J-BAS and Dairy Score should be determined according to the level of co-grazing and contact between the herds. If there is no co-grazing, it may be simpler to have separate plans and scores.

A veterinary advisor should be consulted to resolve complexities such as shared yards.

Will I lose my Dairy Score if I bring in cattle of lower status?

Possibly; there are exceptions.

The simple answer is that cattle should assume the status of the lowest-score animal in the herd. So introduced cattle of lower status would lower the Dairy Score for the property.

However, there are ways that small numbers of lower-score cattle may be introduced and managed without affecting the Dairy Score:

  • Lower-score bulls may be isolated and collected for artificial insemination (AI) without exposing at-risk animals to their higher risk. This option is not likely to be practical for commercial properties which want an introduced bull to be out working, but may be applied for studs.
  • Isolate lower-score females as a separate herd (including progeny); again impractical for commercial dairy herds.
  • Test introduced lower-score bulls or females at regular intervals by faecal testing (not ELISA blood testing). Although this testing can never show that the animals are not infected, consistently negative results can show that the animals are unlikely to have been excreting to spread infection, and so co-grazing breeders and progeny have not been exposed. The cost and inconvenience of this monitoring should be part of the cost-benefit assessment that you make before embarking on this strategy. Also, it does carry a risk of detection of excretion in the lower-status animals, in which case the Dairy Score of the in-contact herd would be affected.

Any strategy for introducing and managing lower-status animals should be, and for Dairy Score 8 herds must be, considered and endorsed by the veterinary advisor, clearly written into the farm biosecurity plan, and monitored to ensure that it operates successfully.

Who signs my biosecurity plan?

At Dairy Score 8, your plan must be endorsed and annually reviewed by a veterinary advisor.

There is no other requirement for a veterinarian or advisor to sign a biosecurity plan.

Where do I lodge my biosecurity plan?

There is no central register of biosecurity plans to lodge or notify.

The plan is useful to you:

  • It can help you to meet the specifications of the new Johne’s disease arrangements, if you want to claim a Dairy Score
  • It can help you to identify and appropriately manage risks of animal diseases (including but not limited to Johne’s disease), crop and plant diseases, pest animals and weeds
  • It is evidence that you meet the LPA requirement from 1 October 2017 for a biosecurity plan.

You should keep the plan secure and readily accessible. You can then use it regularly to guide your approach to diseases and pests and also to support your marketing. If you are satisfied with your plan, you should be OK with showing it to an interested buyer who seeks evidence that your claim of having a plan is valid.

You should also be prepared to review and amend the plan as you learn more about biosecurity or your risks and management change.

Is there a centralised list or database of properties’ biosecurity plans or Dairy Scores or J-BAS scores?

There is no central listing.

Buyers will need to ask vendors or agents for information as part of a transaction.

The industry management system relies on the integrity of producers, especially as presented in health declarations. If you’re concerned about the correctness or completeness of a declared status, you can ask for evidence to support the claim.

The endorsement of a biosecurity plan by a veterinary advisor is the primary quality check, but applies only to the Dairy Score of 8.

Veterinary advice and endorsement is even more credible if provided by JD-trained, preferably CVO-approved vet.

What is the impact on other livestock species?

Beef cattle, dairy cattle, sheep, goats, deer, alpaca and other camelids, and buffalo are all susceptible to JD.

The other industries will be watching the new arrangements for cattle to see whether they have wider application.

At this stage, SheepMAP, GoatMAP and AlpacaMAP are being retained, whereas CattleMAP has ceased and all former CattleMAP herds have transitioned to score 8.

The sheep industry is essentially ahead of cattle, in terms of industry management having replaced regulatory programs in 2013 (except for some areas which established their own Regional Biosecurity Plans).

In recognition of the susceptibility of all species to all strains of JD, the distinction between ovine Johne’s disease (OJD) and bovine Johne’s disease (BJD) is now based on affected host species rather than strain of infection.

For people who co-graze multiple susceptible species, the status for all species must be taken into account when assessing and declaring risk. Depending on the degree and duration of exposure between species, either the non-cattle species may need to be assessed and tested, or the management and testing of the cattle may be regarded as sufficient monitoring of risk across the whole property.

What is the JD risk from feral animals, such as deer?

Deer and goats are certainly susceptible to JD and potential carriers. Other feral and wild animals (pigs, dogs, cats, kangaroos and wallabies, birds) are not considered to be significant carriers.

At present, the prevalence of JD in dairying areas of Queensland is low (but not zero). The risks of feral deer or goats becoming infected and then spreading disease are therefore also low.

The impacts of feral animals on fencing, pasture and safety are much more significant than the risks of them spreading JD.

By far, the greater risk of JD spreading onto a Queensland dairy farm is in cattle introduced for breeding and production, from a source property which is infected but not known to be infected.

This low-risk assessment for feral animals may change if there is a significant spread of JD into and within the dairying areas.

What is the JD risk from creeks and floods?

There are certainly documented cases of JD being spread in water to cause infection on downstream properties.

At present, the prevalence of JD in dairying areas of Queensland is low (but not zero). The risk of infection spreading in groundwater is therefore also low.

Groundwater risk may be mitigated by fencing off creeks and supplying drinking water from bores or on-farm dams.

By far, the greater risk of JD spreading onto a Queensland dairy farm is in cattle introduced for breeding and production, from a source property which is infected but not known to be infected.

This low-risk assessment for feral animals may change if there is a significant spread of JD into and within the dairying areas. You may wish to monitor the trading patterns of upstream properties assess this ongoing risk.

What is the JD risk from spreading manure?

Fresh manure and effluent may carry JD infection; they should not be spread onto paddocks which are to be grazed by cattle less than 12 months old.

Composting for at least two weeks should kill most JD and other infective organisms.

What is the recommended entry standard for a Show?

The entry requirement should be determined by the Show/Sale organisers or committee, in consultation with exhibitors, vendors, buyers and agents. They should also take into account the impacts of other species and breeds at the venue. Ultimately, the entry standard should reflect the demands if the stakeholders and the industry standards.

The new arrangements allow for flexibility; eg, lower risk from young cattle, irrespective of score.

On-site risk management is at least as important as entry standards: site hygiene, clean bedding, separation of stock of differing scores, having cattle especially calves haltered and led when in shared areas such as races and show rings, etc.

Generally speaking the risk of transmission of JD at Shows is low, as attending animals are typically in good health, separated and intensively managed.

How can saleyards manage cattle of different status?

In Queensland, almost every beef property will be J-BAS score 6 or 7 and almost every dairy property will be Dairy Score 7 or 8. There are very few properties with a score of between 0 and 5. Therefore the risk of contamination at a saleyard is very low.

Saleyard operators may wish to protect the score 6, 7 and 8 cattle from risk from score 0 – 5 cattle, such as by requiring a Cattle Health Declaration for all cattle and isolating 0 – 5 cattle and afterwards cleaning their pens. Very few consignments of these low-score cattle would be expected, except possibly cattle from the southern states.

The risk of spread of infection at saleyards between scores 6 and 8 in Queensland at present is low (although this may change over time if management standards allow entry of infection).

Under the new arrangements, individual property owners can take responsibility for dealing with JD risk according to their own needs. Owners of score 7 and 8 properties will want to take more care to protect against entry of infection than those of lower score properties.

The major risk of JD to a Queensland dairy property is the deliberate introduction of cattle which seem to be healthy but are in fact infected. The greatest risk of these animals is cattle originating from dairy herds in the southern states, including those which may have had their origin concealed by subsequent movements and declarations.

How are veterinarians involved?

I strongly urge that that veterinarians engaged in JD work are only those who have completed the JD training which is available free of charge on the Animal Health Australia website, and preferably have proceeded to have that training and APAV accreditation recognised through State Chief Veterinary Officer approval.

The roles for veterinarians under the new industry arrangements are to supervise and endorse the property biosecurity plans (required for Dairy Score 8, recommended for other scores), collect and submit samples for laboratory testing, and provide technical advice such as interpreting test results and assessing risks.

There is no requirement under the new industry arrangements for veterinarians to have undertaken training in JD or to be approved as was previously required by CattleMAP; however the training and CVO approval are the best ways of demonstrating competency in a complex area.

What is involved in HEC testing?

The Herd Environment Culture (HEC) test is a laboratory test on a sample of fresh slurry taken from the dairy yard.

The culture test attempts to grow the causative bacteria from the sample. Due to the slow growth rate of JD, the test requires a prolonged laboratory incubation period of 3 months.

The sample must be collected and submitted by a MAP approved veterinarian or an inspector.

The sampling protocol aims to collect a sample that is representative of the whole herd – i.e. most cows in the herd are represented in the sample.

The yard must be clean prior to bringing the cattle in for milking on the day of sampling.

Sampling is conducted after milking has been completed and before any wash down is started:

  • The faecal material in the concrete yard or standing area in front of the milking shed should be pushed together, using a shovel or a shed scraper following a “W” or “X” scraping pattern across the full length and breadth of the area
  • Thoroughly mix the faecal material in the pile
  • Collect 500 ml of faecal slurry into two large (250 ml) clearly labelled containers
  • The containers should be put into a plastic bag, placed in an esky with freezer bricks, and couriered to the laboratory for culture accompanied by a laboratory submission form.

Refer to laboratory for advice on sample preparation, handling, transport, submission, costs.

In Queensland, the Biosecurity Science Laboratory of the Department of Agriculture and Fisheries is accredited to provide the full suite of tests for JD. Other laboratories are available, but you should check that they hold NATA accreditation for the requested tests and their testing costs.

An important consideration is the specification for culture and HT-J PCR testing that the samples are chilled as quickly as possible and frozen to -80OC within 48 hours of collection.

What is the cost of testing?

Two components:

  • Veterinary sampling and submission
    • Costs determined by practitioner
    • Depend on time, travel distance, facilities, sampling time, transport of samples to lab
  • Laboratory testing
    • Depends on laboratory
    • $143.75 at Biosecurity Sciences Laboratory (DAF) for a HEC test submission.
What regulatory authority underpins the new arrangements?

Johne’s disease is no longer specifically regulated in Queensland, except that:

  • JD is still notifiable: suspicion or confirmation of JD must be reported to Biosecurity Queensland.
  • All people have a ‘general biosecurity obligation’ to do what is reasonable and practical to minimise the likelihood and impacts of spread of infection. With the tools available through the national industry program, what is “reasonable and practical” in the Queensland context of low prevalence could be considered as having a biosecurity plan in place, using a Cattle Health Declaration and J-BAS score to assess and declare the JD risks of all transactions, and securely containing high-risk animals within a property.

The purpose of notifications is for the government to monitor infection to be able to credibly certify exports and to ensure that property owners are aware of their biosecurity obligations. There will be no quarantines applied in response to notification of JD.

Use of the Cattle Health Declaration or Dairy Score assessment tool is not mandatory for Queensland, but their routine use is strongly encouraged both to maintain trade access such as to WA and NT and also to protect against the risk of entry and spread of infection. The use is not mandatory because:

  • Industry has asked government to be able to manage JD without regulatory impost; and
  • It is more important that producers learn to assess and manage JD risks (which are shown through Dairy Score and the Declaration) according to their own objectives, rather than just complying with a requirement to get a piece of paper.

The entry requirements of WA and NT are laid out under their own legislation.

What follows if infection is detected?

As above, suspicion or confirmation of JD must be reported to Biosecurity Queensland (Tel: 13 25 23).

There will be no quarantines or other regulatory consequence applied in response to notification of JD.

The property’s Dairy Score will be affected, according to subsequent management decisions and occurrence of clinical cases.

  • If clinical Johne’s disease (wasting, scouring, unresponsive to treatment) occurs in a home-bred cow, the Dairy Score will be 1 if there is no biosecurity plan appropriate to the occurrence of disease, or 2 if there is a biosecurity plan that addresses the clinical disease and includes the 3-Step Calf Plan.
  • If infection without clinical disease is detected, such as by herd testing, the Dairy Score will be 3, or 4 if there is a biosecurity plan that addresses includes the 3-Step Calf Plan.

Biosecurity Queensland will ensure that the property owner understands their general biosecurity obligation and how they might meet that obligation. Biosecurity Queensland can also provide technical support to the property’s consulting veterinary practitioner to develop a cost-effective approach to managing the disease risk.

Properties which have previously consigned cattle as low-risk may consider advising recipients of those cattle of the revised risk status, so that the recipients can make informed assessment and management decisions.

References & links
Department of Agriculture and Fisheries

 

FutureBeef

 

National industry’s cattle JD tools

 

Biosecurity plans

 

List of MAP-approved veterinarians

 

Biosecurity Sciences Laboratory

Further information
  • Your local veterinarian
  • Your local biosecurity inspector
  • Animal Health Australia