Re: [Alpacasite] Re: Anyone giving BVD vaccine?

I have been at the Northeast Type conference all day where Dr Steve Purdy
did a pre-conference segment on BVD.

There have been a number of emails on the subject today and I will try to
address them here, as well as Neil questions.

I'll start off by saying that there is no clear consensus amongst the
experts on this disease, the appropriate tests and the effectiveness of the tests
in camelids. Most of the research is on cattle. Dr Evans first identified
BVD in llamas in 1988 so this disease has been around for a while. We haven't
heard much about it, I think, because it was not on our radar. I believe the
first (at least one of the first) case identified by Cornell in alpacas
happened at a farm in NY where there was a stillborn. Their vet, who does mostly
bovine, did a necropsy and his bovine necropsy checklist included checking
for BVD.

I would refer you to the Summer 2005 Alpacas Magazine article on BVD for an
excellent overview of this disease and the Winter 2006 issue for a description
of the tests. The 2 PI crias we identified on our farm were diagnosed
through a series of PCR tests and a virus isolation test. Dams of both crias
came to our farm 5 to 6 months pregnant from opposite ends of the country and
appear to have come to our farm with the disease based on the stage of their
pregnancy they came here and the fact that none of our animals are PI (these
animals are boarders). Luck of the Irish I guess that I end up with 2 PI's
born on my farm, but I think it is an indicator that this disease is throughout
the country. We were lucky that one of the 2 PI's was a "slow starter".
When I took him to Tufts Vet Hospital, I requested that they run a BVD test
because I knew of a couple of other farms that have had PI crias this year. If
he hadn't been a bit off, we never would have run the test on him and later on
the rest of our herd and identify the second PI cria. Both crias are now 2
to 3 months old and doing very well (at a horse farm where they are no risk
to other animals).

Dr Evans has been using the vaccine on several herds for years. I cannot
comment on how well it works or how long it is effective, but I have the
greatest respect for Dr Evans and can only assume he would not use it if he didn't
think it was effective. I am not a big proponent of vaccinations, if we can
avoid them. My preference would be to identify those animals who are PI,
preferably through PCR testing at birth. When you run an IgG test, spend $35
and run a PCR test on that cria.

Neil asked if you should test 10 year olds. I think just about everyone
would say no because if they were PI, you would likely have seen problems with
them or their crias, but there are certainly cases in cattle where PI cows
have lived for years and reproduced. If you want to be sure - run tests. A PCR
test, which identifies acute infections (a PI cria will always test
positive), can be run in pools of 10 samples for $35 (Cornell's charge). If the
sample of all 10 is negative, end of story, testing is done and you pay $35. If
the sample of 10 is positive, then they start breaking the sample down into
smaller samples to identify the positive sample and you would be charged based
on the number of tests run. Cornell is very confident that their false
positive rate is low because of their controls. Certainly you would not put down
an animal based on one PCR positive test. If you are concerned about
pregnant females being exposed, run a serum neutralization test (Cornell's charge:
$13). This test identifies antibodies which indicates if the animal has been
exposed to the disease. I would argue that antibodies are good, although I
would like to know if a female has antibodies before she gets pregnant. An
animal that has antibodies has made its ways thru the disease, is not
contagious and is of no risk to your herd (unless she was exposed during the early
stage of her pregnancy, resulting in the possibility of a PI cria which puts
your farm at risk when it is born).

Even though this disease has been a nightmare for my farm, I believe there
should not be hysteria about the disease. It is certainly a problem, but one
that we are now aware of and can address with education and testing. You need
to educate yourself about the disease and assess your level of risk.
Understand that like most alpaca medical issues, the experts do not agree. You
will get very different advice from different vets and virologists. Educate
yourself and decide what you are comfortable with. There is research that is
being done but it needs funding (ARF is sponsoring some research. Tufts is
doing some research and I hope there is a lot more out there). Because of
testing, I now know the risk to my herd of females who have been exposed during
pregnancy and are at risk to produce a PI cria next year because of their
exposure. My plan is to isolate those females from other pregnant females at the
time of birth and test the crias. Just because a female is exposed during
pregnancy and has developed antibodies doesn't mean that the in utero cria
will definitely be PI. Today, Dr Purdy stated that they believe that 1 in 3
will be PI.

Steve McCarthy
Spruce Ridge Farm
Old Chatham, NY
_www.spruceridgefarm.com_ (http://www.spruceridgefarm.com)

In a message dated 12/10/2005 8:17:14 A.M. Eastern Standard Time,
mpcpneilp@aol.com writes:

Steve,

Thanks for the insight. I should have said, "no shows recently, only
males shown in the last year and a half, no outside breedings with
cria by side, and no pregnant females bought in from other farms."

I can certainly have alpacas previously exposed to BVD on the farm,
but they would be immune and not a source of future infection. At
least that is my current understanding.

While I've got you, given that you are now the resident alpacasite
expert on this disease perhaps I can draw upon your knowledge for
alpacasite? Here are some questions;

1)How good is the test(s) for BVD?

2)The vaccine available now (like every other vaccine;-) is bovine.
Does it work well in alpacas? How long is it effective? How sure are
we of this?

3)Thoughts vary on how important a pathogen BVD is in alpacas. Given
what you have been through, in your opinion what reasonable
precautions should the prudent breeder take as of 12/05? In theory,
any alpaca bred and raised on another farm then bought could be a
potential PI. Should we now test 10 year olds? And if they are
positive to the test, can we tell if they are persistently infected
of immune?

Thanks in advance for your further insight. Carol Pfister, if you are
out there feel free to jump in.

Neil
A Paca Fun Farm
Mt. Airy, Maryland
Sugarloaf Mountain, Maryland
www.apacafunfarm.com

--- In Alpacasite@yahoogroups.com, sprucealpacas@a... wrote:
>
>
>
> Neil
> Unless you have tested your herd, I don't think you can make the
statement
> "No BVD here." It is a fallacy that all PI crias are sick. A PI
cria born on
> our farm in September is almost 3 months old now (no longer on my
farm but
> at a horse farm where it can be studied) and she is the "picture
of health".
> Never had diarrhea or a temperature, never lethargic; races around
the field
> like a race horse. It is only because another cria was sick that
we tested
> the herd for BVD and identified this girl as PI. PI cows can live
and
> reproduce for many years.
>
> You refer to shows as your exposure risk. There are many ways to
be
> exposed. Probably the best is outside breedings, especially when a
cria is at side.
>
> As far as vaccines, Dr Evans has been vaccinating herds for
years. See page
> 120 of his new book. He first identified BVD in 1988
>
>
>
> Steve McCarthy
> Spruce Ridge Farm
> Old Chatham, NY
> www.spruceridgefarm.com
>
>
>
>
> In a message dated 12/9/2005 10:14:24 P.M. Eastern Standard Time,
> mpcpneilp@a... writes:
>
> Since we are on the topic of vaccines, here's a question for the
list.
>
> I've been asked off-list twice in the last week if I am giving BVD
> vaccine. I'm not, at least not yet.
>
> Fortunately, since I'm still in the process of building facilities
at
> our new farm I haven't been to a show since MAPACA. No BVD here! I
> don't have to worry about BVD again until March, when I hope to
have
> the new farm finished, be moved in, and have the time to show
again.
>
> So, the question is, who out there is using BVD vaccine. What is
your
> experience? Does the vaccine provide any protection in alpacas?
Any
> adverse reactions to the vaccine?
>
> Neil
> A Paca Fun Farm
> Mt. Airy, Maryland
> Sugarloaf Mountain, Maryland
> www.apacafunfarm.com

[Non-text portions of this message have been removed]

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