A guide to setting up a bovine TB isolation unit
© Tim Scrivener Farmers looking for workable, high-welfare solutions for rearing calves during a bovine TB breakdown should consider making the most of a TB isolation unit.Â
Many farmers are retaining higher numbers of calves in light of new Arla rules, which stipulate that no animal should be slaughtered under eight weeks of age.
This has the potential to create animal welfare issues if a TB breakdown places pressure on stocking densities – an issue that is relevant to all cattle producers coping with TB.
One solution could be to send calves to a TB isolation unit (TB IU).
See also:Â Are Arla producers ready for new rules on calves?
Sarah Tomlinson, Westpoint vet and technical director for the TB Advisory Service (TBAS), Simon Smith, independent consultant, and Stuart Russell, TBAS adviser and vet at Nantwich Farm Vets, share their thoughts on the role of TB IUs.
What is a TB IU?
A TB IU enables a group of cattle to be isolated from the main (origin) herd in a dedicated unit. They are then enrolled in their own testing regime.
Should they go clear after two short interval tests, they receive officially TB free (OTF) status and can be sold to any outlet, regardless of the status of the herd of origin.
These TB-free animals could command a stronger price than those sold during a TB breakdown. It also broadens market options.
How do they work?
Once the TB IU is approved by the Animal and Plant Health Agency (Apha), animals from the herd of origin can move into the unit over a six-week period. A TB IU can only be filled with cattle from a single source.
Cattle move into the TB IU under a movement licence. Animals under 42 days of age do not need pre-movement testing.
Animals older than 42 days must have had a clear test in the previous 30 days.
After the six-week “filling window”, the TB IU is shut, and animals undergo two short interval tests.
If they go clear, this group is OTF and can be sold anywhere.
Who can set them up?
A TB IU can be set up by a farmer on their own farm. Alternatively, it can be set up by another business, as long as it is located in an area of the same or higher TB risk as the farm of origin.
This business could buy animals from the original farm or rear them on contract.
A TB IU must have a separate county parish holding (CPH) number. This is allocated after unit approval.
A TB IU can be considered on all systems. They work well on block calving units, where the calf shed could act as an IU. It can then be filled during a six-week calving period.
Hints and tips
- Every TB breakdown is different, so a TB IU won’t suit everyone. Speak to the TB Advisory Service or your vet for more advice.
- The Apha decision-making process regarding the approval of a TB IU does not appear to be streamlined, so it is worth speaking to the officer in your area before applying.
- It takes time for a TB IU to be approved, so set yours up before your herd gets locked down. This removes the rush of having to get the paperwork agreed (when moving animals more than 42 days old, you only have 30 days to move them into a TB IU after a TB test).
- For the whole herd to go clear, the TB IU needs to be clear. However, a TB IU can go clear, even if the main herd has a breakdown.
How is a TB IU set up?
- The person applying for the TB IU will need to fill out the Application for an approved TB isolation unit (TB136), or via an Apha officer.
- They will then be visited by someone from Apha, who will inspect the suggested TB IU and advise on biosecurity improvements.
- A new CPH request will be made and approval granted.
Main design considerations of a TB IU
- Must be self-contained with separate management, equipment and feed
- Strict biosecurity required for personnel and equipment
- Buildings must provide sufficient space for cattle to grow
- TB IUs (including feed and muck) must be wildlife/badger-proof
- In Wales, cattle in a TB IU cannot be grazed. However, in England, grazing may be allowed, subject to approval from Apha.
Specific guidance may vary between England and Wales. For more details, speak to Apha and check the separate guidance for England and Wales at Gov.uk
Key considerations when establishing an isolation unit
IUs can only be approved on a OTF premisesÂ
Technically, a farm must be OTF to get an IU approved, although farmers have got one approved after being locked down with TB.
To avoid issues, liaise with your local Apha officer.
They are not designed for breeding animals
Pregnant animals should not enter the TB IU and no breeding should take place in the unit.
Facilities should be in place to cope with prolonged restrictions in the TB IU (for example, adequate space).Â
If the TB IU fails its TB test, the origin herd fails too
This is the case even if the TB IU is a separate business.
However, the risk of failure in a TB IU is reduced if the unit is filled with animals less than 42 days old.
The IU affects the origin herd’s status
The timing of when cattle move into a TB IU has implications for when the origin herd can be declared OTF.
Problems have occurred when a herd has sent calves to an IU after TB testing has begun in the herd of origin.
In this case, if the herd of origin goes clear of TB on its two short interval tests, it cannot be declared OTF until the IU has completed its testing regime.
This could delay achieving OTF in the origin herd by up to 120 days.
To avoid issues, do not overlap a TB IU filling window with TB testing in the origin herd. Instead, coincide the opening and closing dates and testing dates of the IU with the filling window.
Consider options for the TB IU once it has been depopulated
A TB IU is temporary, so once the unit has been depopulated, a new application must be made for reapproval of the unit.
After depopulation, a farmer will need to think about whether to keep the CPH or archive it. Speak to your local TBAS or Apha officer for advice.