SAC Symposium - The Bleeding Calf Syndrome - Fiona Howie: Transcript
Ken Rundle: You are listening to an SAC podcast from SAC’s Herd Health Symposium held as part of the VET Trust’s CPD event at Stirling. This event was funded by the Scottish Government under its Veterinary and Advisory Programme or VAS.
Bleeding Calf Syndrome or BNP as our mainland European colleagues call it has emerged as a new disease resulting in significant calf death amongst beef herds in Scotland and the UK. I have asked SAC Veterinary Investigation Officer, Fiona Howie, to explain more about it.
Fiona, what kind of disease is it?
Fiona Howie: It is a disease that causes bleeding, haemorrhaging. It is quite a devastating disease to the individual animal, the individual farmer, very dramatic, but it in fact affects quite a small proportion as you will have heard from my colleague, George Caldow, so in life we are looking for animals that are bleeding, perhaps as a result of ear tagging, or an injection site and then at death you find very widespread haemorrhages inside the body.
KR: The calves don’t live long?
FH: The calves don’t live long. Sometimes they are dull or other times they are simply found dead with no history of haemorrhage at all but they die either as a consequence of blood loss directly or because all the blood cells are affected, the inflammatory cells that fight infection are affected as well so they can die as a result of infection because they can’t fight it.
KR: So far at least, what do we know about what causes this disease?
FH: The most recent studies undertaken indicate that it is linked to the use of a particular BVD vaccine, Pregsure. It is caused by the cows producing antibodies not just against the BVD vaccine but against the cell components of individual calves so unfortunately when the calves have colostrum, the colostrum knocks out and kills the blood cells and the bone marrow that makes the blood cells.
KR: That particular vaccine against another disease in cattle has been withdrawn from the market. Are we seeing any reduction in the disease now?
FH: No we are not. We are seeing almost exactly the same number of cases this year as we were seeing last year and bear in mind that SAC was offering free post mortem examinations last year and yet we are still seeing the same number of cases this year. I think it will be with us until every cow that was vaccinated with Pregsure is no longer in the national herd.
KR: It would seem to indicate that it is long-lasting and not just down to one dose of a vaccine.
FH: That’s right. These of course are cows that have not been vaccinated with this vaccine in this pregnancy and some perhaps haven’t even received the vaccine for 2 years but, yes, the calves are still affected.
KR: So what are you advising farmers to do?
FH: We are advising that, if they know that the cows had a history of losing a calf to BNP before, that they snatch the calf and it gets colostrum from a cow that has had a healthy calf in the past and don’t pool colostrum, don’t bring colostrum in from another source. It’s not perfect because of course a cow that you thought was fine could produce the dangerous colostrum but that is the best advice we can give.
KR: And it’s not just bleeding you need to look for that’s the other thing.
FH: That’s right. They can present just as sudden death. You can go out in the morning and find your calf lying dead and it is due to haemorrhage but you don’t find that out until post mortem examination because the haemorrhage is all contained inside the body.
KR: And you have mentioned post mortem there, and that’s the important thing, that farmers keep you in touch with this if we are going to get a grip of this we need to know what’s happening.
FH: That’s right. You can investigate the likelihood of BNP using blood samples in live calves and that helps with prognosis but you have to carry out a post mortem examination and examine the bone marrow to allow a conclusive diagnosis and, as I say, it can be a simple sudden death so you could miss it.
KR: Now this has been mentioned elsewhere in our podcast but we are not advising necessarily that people don’t vaccinate against BVD.
FH: Absolutely not. Vaccination is the best tool we have to offer to keep herds healthy. Vaccination is very safe and again even with this I would emphasise that the number of cases is very small.
KR: And there are other vaccines available.
FH: And there are other vaccines now on the market to replace the one that has been withdrawn.