The Accidental Smallholder Forum
Livestock => Camelids => Topic started by: nutterly_uts on June 12, 2015, 10:18:55 pm
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I hope this isn't a pandora's box! I am trying to get this sorted in my head but I don't know where to start so any info please!
I understand that Alpaca can carry TB, and that cattle owners need to test for TB. Do sheep owners? I have a feeling that the skin test in alpaca doesn't work a lot of the time, so is it possible to screen alpaca for TB, and also is there any form of vaccine they can be given?
Is it possible to keep alpaca on the same area as cattle? Not the same fields, but on the same holding? What about sharing fields with sheep? Is there any thing that can be done to minimise the TB risk or does it remain a bit of a gamble?
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Short answers:
It is. We'll try.
They can, and they do. No, they don't. That is correct and not as far as I know, and absolutely not.
Yes it is. Yes. It is a bit, but you can weight the odds by sourcing your stock carefully and maintaining a double barrier between yourself and your neighbours.
More detail:
Alpaca can carry TB and can infect their human owners. There is a test for cattle but no reliable test for camelids. (At least, as far as I know. I'm not a camelid expert and of course the scientists are working on all this.)
Whilst TB lesions are also found in sheep and goats, pigs and a few other species from time to time, it does not seem that TB in these species leads to any problems in other species on the holding nor in humans.
All cattle have to be tested regularly; how frequently depends on the risk level of the farm. All of Scotland and much of the far north of England is classified as 'TB4', which means testing is on a 4-year cycle. Certain parts of the south-west, Wales and the Midlands have to test once a year; and if a farm has had a breakdown then it has to test every 60 days I think it is, until it tests clear for two consecutive tests. (I think; we're TB4 here so I'm not as familiar with the regime in higher risk areas.) Farms which sell or use unpasteurised milk have to test every year, no matter what risk category their area.
If an animal is to be moved into a lower-risk area than it's coming from, it has to be tested clear before movement and be tested again 60 days after movement. The occasional case in Scotland or the far north of England is generally a result of a moved animal failing its post-movement test.
The test for TB in cattle is a skin test. TB antigens are injected into the skin. If the animal has antibodies to TB, the skin will thicken. After three days, the skin is inspected; if it has thickened significantly then the animal is a possible reactor and further tests will be done. If the animal does prove to have antibodies to TB in its blood, it will be destroyed and the farm will be unable to sell or move cattle until it has had two consecutive clear tests.
The issue about vaccination is that once an animal is vaccinated, it has antibodies to TB and therefore it is impossible to tell an infected animal from a vaccinated animal without killing it. The scientists are working on vaccines that would leave different markers in the blood so that a vaccinated animal can be differentiated with a blood test - but the skin test would no longer be the relatively quick, simple and non-invasive procedure it is.
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If you must have alpaca, here are my suggestions for minimising risk:
- if your neighbours have cattle, do not keep your alpaca next to your neighbour's cattle. If your area is TB4, this is mainly for the sanity of your neighbour! If your area is higher risk then it minimises risk for both parties of TB crossing the fence.
- Double fence lines with good air gaps between will of course minimise risk of transmission beast to beast.
- Buy your alpaca from an area that is TB4. (I'm sorry all you alpaca-breeders further south, but it's the truth.) Only buy alpacas bred on the farm, and only from a farm which has never had a TB breakdown. Ideally a farm which has cattle and has had a recent TB test.
- Once you have your alpaca, be very robust about bringing in other camelids and cattle. Ideally from TB4 only.
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Thank you :)
Sounds like alpaca on a farm with cattle is just too risky
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Although, if you are in a high risk TB area and do yearly testing, does that make getting alpaca more risky or less? I'm having a lack of brain cells moment and cannot get my head round it
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If you must have alpaca, here are my suggestions for minimising risk:
- Double fence lines with good air gaps between will of course minimise risk of transmission beast to beast.
Yes, agree.... works best with weld mesh dug into the ground about 4-5 feet and six foot high!
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Although, if you are in a high risk TB area and do yearly testing, does that make getting alpaca more risky or less? I'm having a lack of brain cells moment and cannot get my head round it
Personally I'd say more, in that the alpaca would be susceptible to it and not testable, and anyone in a high risk area is of course always at risk of having one of your cattle be a reactor.
So if it got onto the holding, however it arrived, the alpaca could become a pool for reinfection of the cattle. Not to mention silent carriers that could infect their owners - that's YOU!
If you were in a TB4 area and took all precautions on selecting and bringing in your foundation beasts, and then kept a closed herd, in my head that's less risky.
You'll sense that I am not a fan and do have a bee in my bonnet about TB, though - we could maybe do with hearing from any alpaca-keepers?
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BTW - goats can and do get TB and will also infect their owners if in close contact at milking time for example. Test as unreliable as in cattle, inasmuch that there have been cases of reactors that were found not to have TB at pm. Seemingly an increasing problem in the large dairy herds...
Goats can now be tested at the request of DEFRA/AH and the herd is destroyed the same way as for cattle, BUT no compensation available...
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Going off topic a little, but that is interesting about no TB at pm in reactor cattle. In humans we often used to see small areas of calcification on chest x- rays which were known to be healed primary pulmonary TB, with the person healing in their own without antibiotics. They would have still shown a positive reaction of Heaf testing. I assume the same can apply to cattle - they have been infected, recovered but have antibodies which will give the skin reaction at testing. I feel there is a lot we don't know about the natural history of TB in cattle, but I can understand not allowing cattle to progress with the diesels to see how many get better and how many go on to succumb. I suppose the only way to find out would be to take a herd, keep them in isolation and see what happens. But difficult to do a chest x- Ray on a cow though !
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PM is not reliable as a test for Tb as it is crude, a man slices up the animal looking for Tb lesions. If the Tb is not advanced and lesions are small they may be missed. Just because it isn't seen does not mean the animal is clear. Herds on 60 day tests for eg. rarely do they find lesions at PM as reactors are removed every two months - I wonder why they look once Tb has been confirmed in one animal. It just confuses people.
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PM is not reliable as a test for Tb as it is crude, a man slices up the animal looking for Tb lesions. If the Tb is not advanced and lesions are small they may be missed. Just because it isn't seen does not mean the animal is clear. Herds on 60 day tests for eg. rarely do they find lesions at PM as reactors are removed every two months - I wonder why they look once Tb has been confirmed in one animal. It just confuses people.
What about the culture test after PM? Is that more reliable, or hit or miss depending on where they cultured from?
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I find it quite amazing that you can go to an area rife with TB. . . . . intact a farm knowingly infected with TB. . . . . . buy an Alpaca and take it anywhere you like without testing it!
To be honest the U.K would be a better place if the bloody things had stayed in South America! I have yet to find a purpose to them. . . . . . apart from wasting ground, passing on T.B and making money for those that peddle them to small holders.
Oh wait. . . . scratch that. . . . . I once had a bloody good Alpaca burger!
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Goats can now be tested at the request of DEFRA/AH and the herd is destroyed the same way as for cattle, BUT no compensation available...
just to be clear ... the herd in cattle is not destroyed only the reactors.
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... and from a moderator .... please keep your comments to the question asked and avoid personal comments about Alpacas...
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Lots of information on Alpaca TB at: www.alpacatb.com (http://www.alpacatb.com)
Camelids can be tested for TB with a blood test at a APHA lab for around £20 per animal. This test has to be requested through your vet. However, whilst the tests have a high specify, they still have a relatively low sensitivity in some circumstances.
7 herds were identified in England and Wales last year as having camelids with TB confirmed by AHVLA test, Link to DEFRA stats (https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCIQFjAAahUKEwiDp4KQmI3GAhWFPxQKHWgYAA4&url=https%3A%2F%2Fwww.gov.uk%2Fgovernment%2Fuploads%2Fsystem%2Fuploads%2Fattachment_data%2Ffile%2F401332%2Fbovinetb-otherspecies-04feb15.xls&ei=e2d8VcP9D4X_UOiwgHA&usg=AFQjCNEKRHlG58nQc1nLZXN8Iba4ejl9Ug&sig2=ynhgcpuFT_T-F_zn9bsilA&bvm=bv.95515949,d.d24) though, of course this is just those tested so does not give a full picture.
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PM is not reliable as a test for Tb as it is crude, a man slices up the animal looking for Tb lesions. If the Tb is not advanced and lesions are small they may be missed. Just because it isn't seen does not mean the animal is clear. Herds on 60 day tests for eg. rarely do they find lesions at PM as reactors are removed every two months - I wonder why they look once Tb has been confirmed in one animal. It just confuses people.
What about the culture test after PM? Is that more reliable, or hit or miss depending on where they cultured from?
So,
1. I can't tell you off the top of my head how sensitive (likely to find tb if it is there) and specific (how likely it is to tell you tb is there when it is not) the tests are alone and used in tandem
2. I am too lazy to look up the answers and look clever
3. This seems to have some answers but I am not sure as too lazy to read it all through - enjoy! ;)
4. But its just lifted from tinternet so cannot say it is accurate http://www.dardni.gov.uk/afbi-literature-review-tb-review-diagnostic-tests-cattle.pdf (http://www.dardni.gov.uk/afbi-literature-review-tb-review-diagnostic-tests-cattle.pdf)
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I hope this isn't a pandora's box! I am trying to get this sorted in my head but I don't know where to start so any info please!
I understand that Alpaca can carry TB, and that cattle owners need to test for TB. Do sheep owners? I have a feeling that the skin test in alpaca doesn't work a lot of the time, so is it possible to screen alpaca for TB, and also is there any form of vaccine they can be given?
Is it possible to keep alpaca on the same area as cattle? Not the same fields, but on the same holding? What about sharing fields with sheep? Is there any thing that can be done to minimise the TB risk or does it remain a bit of a gamble?
I think people who milk sheep and make cheese or sell it have to TB test their sheep, I have a friend who had to do this. I never knew they could get TB but apparently they do. ???
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PM is not reliable as a test for Tb as it is crude, a man slices up the animal looking for Tb lesions. If the Tb is not advanced and lesions are small they may be missed. Just because it isn't seen does not mean the animal is clear. Herds on 60 day tests for eg. rarely do they find lesions at PM as reactors are removed every two months - I wonder why they look once Tb has been confirmed in one animal. It just confuses people.
What about the culture test after PM? Is that more reliable, or hit or miss depending on where they cultured from?
So,
1. I can't tell you off the top of my head how sensitive (likely to find tb if it is there) and specific (how likely it is to tell you tb is there when it is not) the tests are alone and used in tandem
2. I am too lazy to look up the answers and look clever
3. This seems to have some answers but I am not sure as too lazy to read it all through - enjoy! ;)
4. But its just lifted from tinternet so cannot say it is accurate http://www.dardni.gov.uk/afbi-literature-review-tb-review-diagnostic-tests-cattle.pdf (http://www.dardni.gov.uk/afbi-literature-review-tb-review-diagnostic-tests-cattle.pdf)
Thanks. That says the culture test is the gold standard but is highly specific and not very sensitive. But now I'm wondering what is the definition of "having TB" anyway! The vaccine research I posted earlier (different thread) considered animals not to have TB if the PM and culture test were negative. Science, so messy when you look close :P
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Lots of information on Alpaca TB at: www.alpacatb.com (http://www.alpacatb.com)
That website is showing 86 herds of camelids in England and Wales tested positive by the end of 2014 :o
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The thing with TB is when they test them and it shows positive it could just be a skin reaction, but they cannot take that risk just in case. Also TB develops over a long time period, so they cannot afford to wait and see in case other animals get infected.
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Lots of information on Alpaca TB at: www.alpacatb.com (http://www.alpacatb.com)
That website is showing 86 herds of camelids in England and Wales tested positive by the end of 2014 :o
That is since 1999. 7 of those were in 2014.
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Lots of information on Alpaca TB at: www.alpacatb.com (http://www.alpacatb.com)
That website is showing 86 herds of camelids in England and Wales tested positive by the end of 2014 :o
That is since 1999. 7 of those were in 2014.
Ah :idea: Thanks for the explanation! :D
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Thanks for all the info :)
I've crossed 'paca off the list as friend has just had his first ever TB reactor and so anything that makes this journey possible again is outta here..