Author Topic: Schmallenberg virus - some useful info  (Read 4484 times)

oaklandspigs

  • Joined Nov 2009
  • East Sussex
    • OaklandsPigs
Schmallenberg virus - some useful info
« on: February 26, 2012, 06:18:09 pm »
I went to a meeting on Thursday about this disease, and wrote up some notes.  Those with sheep and cattle that have heard about this virus might find them of interest !
If this is the first time you have heard this phrase, then the following article gives somebasics, but is newspaper language so life is about to end!
http://www.telegraph.co.uk/earth/agriculture/farming/9105880/Fears-of-catastrophe-as-new-virus-hits-farms.html
Key points from the meeting I went to run by Westpoint Vets with ADAS and the NFU
In the audience of 100 or so, of the 6 farmers that had started lambing 5 had deformed lambs. Rate was 5-15%.
There is a large amount of re-absorbsion from data from those that scanned – singles coming up empty, and twins only having singles – anything up to 10%
Lambs born can be stillborn, can be deformed with locked joints making it very hard for the sheep to lamb – one person said she was regularly breaking lamb legs inside the sheep to get out dead deformed lambs so as to save the sheep.
There are also what are called “silly lambs” – born live but with little brain development, so die quite quickly.
Any like the above can be sent free to AHVLA for SBV analysis (they only test for that, they won’t tell you about anything else unless you pay), and are likely to only do the first positive one, then they are not asking for more.  As cases build this may stop altogether.
All you can do for this year’s lamb crop is cope.
As for future, all the following needs a big caveat – this is an early disease, with little history, however bluetongue spread (also by midges) gives us good data from past, and some of Europe is months ahead of us in lamb cycles so have been through it.  There is also excellent cross European co-operation and information sharing.
However the following is best guestimates from informed sources.  So likely to be true, but not guaranteed!
For sheep, once infected they show no signs of illness, but have it for a couple of weeks.  They then have developed strong immunity to it (potentially life long!).  So once a sheep has had it, it should be ok.
For cattle, they show lots of symptoms that are common with other diseases, but similarly they then have developed strong immunity to it, and should the  be ok.
The issue is IF they get infected or have the virus during the first trimester of pregnancy.  Before mating or after the first trimester and the offspring is not affected. (don’t know whether the yoing inherit the immunity, but if meat doesn’t matter, and for future breeding as long as they get it before mating, then they’ll be ok.
Midges are the likely source of infection, and this is borne out by Defra’s modelling of midge vs. Wind and temperature that shows most danger area is where we are seeing the virus.  Midges are active only at certain temperatures, and the likely period when they can affect is march to October, although that doesn’t mean you can relax on November the 1st!!
Parasite control of the flock/herd may reduce spread, but standard fly protection products don’t do midges, you need spot-on.  However you are too late to help this year and see below may positively want to welcome it now, so consider this before using spot-on.  If you use spot-on on a sheep, then it will kill the midge that bites it, but not before it has infected the sheep, and probably not before it has infected several others of your flock – the poison takes up to a hour or so to work,  so at best you might reduce, but would not protect.
A vaccine is 1-2 years away, and probably won’t be needed as by the time it gets here, all sheep and cattle should have got it (and got over it).
If you are in the south then your strategy is that for this seasons lambing, you will have what you have got now, so cannot do anything about it.  If it proves that once infected you get a long period of immunity, and for sheep there are no side effects, then maybe you should hope that all your sheep get infected during this summer, and then they’ll have protection and next year you’ll be ok, as protected sheep don’t produce deformed/stillborn/silly lambs.
For cattle in the south, the same strategy might apply, hope that they get it, that you don;t get too bad symptoms (eg milk reduction) which only lasts for two weeks in any case, and they get immunity for next year.
Those in the south will also need to consider whether they should buy in stock from the north, that will be naive to the disease (not have had it), and whether to do this earlier so that they might/should get the disease before going to ram/bull or AI.
For those outside the immediate area infected this year, it will depend on how quickly midges spread up north from infected south.  If slowly, then you might get several years of uncertainty (there is no live test at the moment to see if stock has had it) as to whether your particular area has got it/your farm has  got it.  I did ask about deliberately infecting stock so that they get it and get over it – and this might be a possibility  if vaccine doesn’t get here soon.
So that’s what I learnt.  In a way you should hope that all the UK gets it this summer, and then with a long immunity the worry will disappear, although we might be vaccinating future breeding stock in their first lambing/calving season to give their young protection.
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Rosemary

  • Joined Oct 2007
  • Barry, Angus, Scotland
    • The Accidental Smallholder
Re: Schmallenberg virus - some useful info
« Reply #1 on: February 26, 2012, 08:38:46 pm »
Thanks for this - just hope it burns itself out before getting here  :(

robert waddell

  • Guest
Re: Schmallenberg virus - some useful info
« Reply #2 on: February 27, 2012, 12:06:34 am »
if it takes them as long to get sorted out as they have with bvd there will be even less cattle and sheep >:( :farmer:

Southfields

  • Joined Mar 2011
  • Salisbury
Re: Schmallenberg virus - some useful info
« Reply #3 on: February 27, 2012, 08:34:36 am »
Thanks for the great post.  Keeping our fingers crossed down here!

Small Farmer

  • Joined Jan 2012
  • Bedfordshire
Re: Schmallenberg virus - some useful info
« Reply #4 on: March 05, 2012, 08:49:01 am »
We had another education evening with ours local vet the other day and he included a session on schmellenberg.  He pointed out that the abnormal births are a consequence of the disease, rather than the disease itself which has departed from the mother well before birth.  It makes identification more difficult.

In Herts there has been one possible case with a deformed calf born in Potters Bar but they don't really expect to see any real numbers until May/June if the same midges that affected the sheep are involved.

He thought he might have had a case yesterday when he had to do a Caesarean but it turned out merely to be a  67kg calf! 
« Last Edit: March 05, 2012, 09:05:57 am by Small Farmer »
Being certain just means you haven't got all the facts

 

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