Gamma TB test

sidjon

Member
Location
EXMOOR
If your in a cull area you will have no choice if a new breakdown.

Another new rule is that IR's have to stay on the farm that they were found to be an IR for life even if they go clear at the next test..

All agreed by the NFU so im told.

I know of a farm where they had 10 reactors and 21 IR's out of 70 cows, next test did the blood test as well, they have now got 21 cows left...

Out of all the cattle they took all the skin tested all bar one reactors had Lesions on kill, out of the blood tested ones taken they found lesions in 1 animal...
Guess they might as well forget IRS and just have reactors, probably 60% of our 500 head will have been IRS,
 
Obviously. TB is a slow growing chronic disease. You'd expect those that passed the skin test but failed with gamma interferon to be earlier in the course of disease and not to have developed lesions. It doesn't mean they don't have TB......

It is a slow burn disease for sure, but look up Burrough Farm Partnership, who several years ago headed a High Court challenge into their 400 + gamma reactors. This process took months and months. And failed. Defra took the lot . No lesions. No cultures. (From memory)
Another farm was instructed to skin test all cattle on the farm, in the usual computer generated letter. He complied quickly, including 30 something gamma reactors awaiting the result of this
Court case and which had been on the farm for months.
They passed. Defra still slaughtered them. No lesions.

PQs gave us 221 days from exposure to m.bovis to disease for U.K. strains.

Some vets think that positive gamma reactors which show no lesions and fail to culture, are animals which have met m.bovis and have beaten off the disease. They will still have antibodies. So what .Defra are doing is leaving any increasingly naive population of cattle, exposed to increasing levels of 'environmental' contamination....... as they so quaintly describe infected badgers.
 
Last edited:
Location
Devon
Obviously. TB is a slow growing chronic disease. You'd expect those that passed the skin test but failed with gamma interferon to be earlier in the course of disease and not to have developed lesions. It doesn't mean they don't have TB......

Skin test about 70 have lesions.

Blood test 3% have lesions.

Say a farm has 100 reactors from the blood test, 3% will have lesions on kill, no way in hell that ALL the other 97% would have gone on and became infected if they were only tested by using the skin test..

Compensation rates are diabolical and farms cannot afford to have so many cattle taken using the blood test when its so inaccurate..
 
Location
Devon
Guess they might as well forget IRS and just have reactors, probably 60% of our 500 head will have been IRS,

TBH given the new rules and the fact they are now taking so many IR's at the first reading if you also have reactors at the same test then they should do away with IR's and cattle should either be clear or reactors.

Been told ( no idea if its correct thou ) that a dairy herd of over 200 head the other side of SM have all been taken as over 60% were reactors in a recent test.
 

bovine

Member
Location
North
I'm not getting drawn into a TB thread as there is too much emotion. We know there will be false positive results with the gamma interferon test and there will be extreme example (like @matthew mentions) where there were large numbers of false positive results, but it remains a useful test to help remove early infected cattle from a new breakdown herd. I'm not going into detail but we've had a number of breakdowns with bought in cattle and the gamma interferon has helped to rapidly clear infected animals from the herds (admittedly we don't knowingly have it in the wildlife).

In a known infected herd the likelihood is that many of the positives are true positives. It would be a crap screening test. It does have a useful place in TB control and linking rates to visible lesions is pretty meaningless.
 

sidjon

Member
Location
EXMOOR
TBH given the new rules and the fact they are now taking so many IR's at the first reading if you also have reactors at the same test then they should do away with IR's and cattle should either be clear or reactors.

Been told ( no idea if its correct thou ) that a dairy herd of over 200 head the other side of SM have all been taken as over 60% were reactors in a recent test.
Heard about herd at SM , think they were left with 21animals which now have been slaughtered.
 
Location
Devon
I'm not getting drawn into a TB thread as there is too much emotion. We know there will be false positive results with the gamma interferon test and there will be extreme example (like @matthew mentions) where there were large numbers of false positive results, but it remains a useful test to help remove early infected cattle from a new breakdown herd. I'm not going into detail but we've had a number of breakdowns with bought in cattle and the gamma interferon has helped to rapidly clear infected animals from the herds (admittedly we don't knowingly have it in the wildlife).

In a known infected herd the likelihood is that many of the positives are true positives. It would be a crap screening test. It does have a useful place in TB control and linking rates to visible lesions is pretty meaningless.

No offence Bovine but its totally flawed thinking from profesionals like yourself is the biggest reason TB has been allowed to get totally out of control..

You cannot say: Oh it doesn't matter if the animals have Lesions or not but the blood test is effective when the majority of the animals taken by the blood test will never go on to have TB unlike the Skin test when 70% have lesions and the blood tested cattle only have 3% lesions on Kill..

Take cancer in Humans, no doctor would use a test that is 97% inaccurate ( ie throwing 97% false positives ) to decide if people have cancer or not.

70% accuracy isn't good enough but 3% accuracy is a complete nonsense!
 

bovine

Member
Location
North
The skin test is way more than 70% accurate

http://veterinaryrecord.bmj.com/content/177/10/258

In most infected herds the majority of positive results with the gamma interferon test will have TB or have been exposed to TB. The accuracy is nothing like as low as 3%, there are just so many other possible factors at play that make putting an exact number on that impossible. You wouldn't expect to find lesions in these positive cattle, it doesn't mean they aren't going to go down with TB.
 
Location
Devon
The skin test is way more than 70% accurate

http://veterinaryrecord.bmj.com/content/177/10/258

In most infected herds the majority of positive results with the gamma interferon test will have TB or have been exposed to TB. The accuracy is nothing like as low as 3%, there are just so many other possible factors at play that make putting an exact number on that impossible. You wouldn't expect to find lesions in these positive cattle, it doesn't mean they aren't going to go down with TB.


Actually on farm results show that around 7 out of 10 cattle killed as reactors under the skin test have lesions and that only 3% of blood tested cattle taken as reactors have lesions on kill..

By your way of thinking given the large numbers of cattle being taken in tests using the blood test then most farms would lose most of their cattle before they go TB clear but the reality on the ground shows that this is NOT the case if only the Skin test is used yet the herds go clear until the following grazing season when the cattle come into contact with infected animals again!

All other country's rely on the Skin test and the culling of infected wild animals to deal with the Tb problem and its working 100% in 100% of country's that use these methods..

We haven't been culling wild animals and are now using a blood test that is so inaccurate that the results are almost worthless and look what a mess TB is in this country..

If the blood test was 85/90% accurate then it should be used, reality is that its far more inaccurate than the Skin test and is taking 1000s of cattle needlessly at massive costs to farmers and thus it has no place in TB controls in places like the SW where TB is endemic in the wild badger and red deer population.
 

bovine

Member
Location
North
Actually on farm results show that around 7 out of 10 cattle killed as reactors under the skin test have lesions and that only 3% of blood tested cattle taken as reactors have lesions on kill..

Fine, but most of those cattle still have TB. That's the part you are glossing over. You don't have lesions or culture positive even when they actually have the disease, we just need to find the TB bacteria to spoligotype etc.

You seem to think that no lesions = no TB and that's just wrong.
 

Thick Farmer

Member
Location
West Wales
Fine, but most of those cattle still have TB. That's the part you are glossing over. You don't have lesions or culture positive even when they actually have the disease, we just need to find the TB bacteria to spoligotype etc.

You seem to think that no lesions = no TB and that's just wrong.

How much are vets paid for TB testing and reading these days?
 

kmo

Member
Location
E. Wales
Is gamma interferon still only a test for adult cattle now?
Following a breakdown a few years ago I was informed that a gamma interferon test was needed. But before they did the test they first needed to come do a risk assessment on my handling facilities.
So vet drives up hour and three quarters from Carmarthen. Jumps out of car, looks around and asks "Where are your cows?"
I don't have any cows, young stock only.
"Oh we cant do a gamma interferon test then" she says.
Get's back in her Audi and does the seventy miles back to Carmarthen.
 

bovine

Member
Location
North
upload_2017-4-20_23-40-56.png
 

bovine

Member
Location
North
You do it for the love of the job?

I have to lose two days pay and also pay men to help me make the job easy for the vet.
No I do it so I don't have other vets on my clients farms. I do it for (hopefully) goodwill and to keep more vets on the OOH rota.

It's not profitable work for the practice when you take into account the costs for accreditation, training, audit etc.
 

Thick Farmer

Member
Location
West Wales
That's it for the 2 days testing and the arranging tests and admin and time booking the work. No extra for mileage.

So for just an average 200 cow her with followers and a few beef ( say 400 head you get around £1000.

On some of the big herds around here with over 2500 head of stock it's likely to be £4500 plus. No really a bad return for just a a bit of trimming, injecting and smoothing necks!
 

bovine

Member
Location
North
So for just an average 200 cow her with followers and a few beef ( say 400 head you get around £1000.

For 400 animals we would get £834.50, but (what I forgot to say) is XL Farmcare take 35p each animal for admin, so we lose £140 and bank £694.50

It's nice on organized farms to do 50 an hour but unless everything is exceptionally well set up that rarely happens. Often animals are at multiple sites so there is different set ups to contend with, down time moving equipment etc. There is 8 hours of solid work if you can keep them coming through at 50 per hour without a break to pee, drink a cup of tea or eat something. You would have a vet tied up for 2 days or even sometimes split because of staff/equipment etc

Typical hourly rates for a vet would be around £120 per hour. That is 5.8 hours of vet time and you are tying up 16+ hours where they could be doing something more profitable. Worse as we are 4 yearly testing so the facilities are generally poor and not set up like they are down in the south west where they test every 60 days.

We've spent £1000 this year training a new vet to TB test and everyone else revalidating their 'grandfather' rights.

Not to mention it's boring and often dangerous work for a highly trained professional person. I don't know of any vets who enjoy testing.
 

SFI - What % were you taking out of production?

  • 0 %

    Votes: 78 42.9%
  • Up to 25%

    Votes: 63 34.6%
  • 25-50%

    Votes: 30 16.5%
  • 50-75%

    Votes: 3 1.6%
  • 75-100%

    Votes: 3 1.6%
  • 100% I’ve had enough of farming!

    Votes: 5 2.7%

Red Tractor drops launch of green farming scheme amid anger from farmers

  • 1,286
  • 1
As reported in Independent


quote: “Red Tractor has confirmed it is dropping plans to launch its green farming assurance standard in April“

read the TFF thread here: https://thefarmingforum.co.uk/index.php?threads/gfc-was-to-go-ahead-now-not-going-ahead.405234/
Top