SAC Symposium - The Bleeding Calf Syndrome - George Caldow: 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 on 14 and 15 June. This event was funded by the Scottish Government under its Veterinary and Advisory Programme or VAS.
Bleeding Calf Syndrome or BNP emerged as a new disease causing significant calf death amongst beef herds in Scotland and the UK. Investigation of BNP in Great Britain has involved vets, veterinary pathologists, veterinary virologists and epidemiologists from SAC, Moredun and the Veterinary Laboratories Agency. With me is SAC’s Veterinary Manager, George Caldow.
George, you have been involved in one of these epidemiological studies. What kind of study was it?
George Caldow: We carried out initially a case series in a case control study looking at BNP as it occurred throughout GB. We worked very closely with our colleagues in VLA and Moredun to review the disease and to identify the factors that were important in the occurrence of this new disease.
KR: You have had to take very great care that you were getting accurate information that involved controls and a whole series of questionnaires.
GC: Yes. Our case series study initially set out to identify the factors that were present in these cases of BNP as they occurred. From that our findings informed the construction of our case control study and what a case control study seeks to do is to draw comparisons between the factors present in the cases with a randomly selected collection of control farms. So each farm in the case control series was visited by a vet, the questionnaires were carried out and then we analysed the presence or absence of these factors to identify what the major risk factors in this study were.
KR: That study has recently gone onto the Defra website. What are the key findings?
GC: We carried out the study throughout the course of 2010, analysed the work towards the end of 2010 and presented the results at the beginning of 2011 and the results are now released. What the study has shown is that it supported the work that had been done in other countries throughout Europe that there were an association between a particular BVD vaccine and the occurrence of BNP.
KR: What were the results of that study?
GC: We found 3 factors that were associated with the disease. Firstly our case series suggested that the cases were more likely to occur in Scotland. But when we looked at the pattern of cases as they occurred we saw that we initially had more calves born early in the case control series in Scotland than had occurred in England and that probably explains why we have more cases in Scotland. The second factor was in association with sheep and that’s probably also related to the Scottish cases because most of our cases were typical Scottish farms where you have beef cattle and sheep going on the same premises. The final factor and important one was that we found an association with a BVD vaccine which resulted in a minimum of a 10 times increase of the occurrence of BNP occurring where the dam of the calf had been vaccinated with this particular BVD vaccine.
KR: So, the BVD vaccine was given to the cow to prevent another disease but it seemed to be linked to this new disease.
GC: That is correct. What it seemed to be doing was stimulating antibody which was then passed on in the colostrum to the calf which attacked the bone marrow of these calves. The work that we have done in our studies supports the work that has been done elsewhere in Europe and the findings are very similar so we have identified an association between this vaccine and the occurrence of this disease and there is further study going on, in particular at the Moredun Research Institute, to unravel the exact way that the disease works but currently the important message is that this vaccine is no longer available for use anywhere in Europe and there are another 2 options for BVD vaccination so that the herds will continue to be able to be protected against this particular disease and furthermore there has been absolutely no association shown between any other cattle vaccine and the occurrence of this disease.
KR: So it’s a case of carrying on with vaccination of the right kind with advice from your vet.
GC: I would say that unreservedly. The vaccination is a key part in protecting our herds and a well thought out vaccination plan goes a long way to ensuring health and productivity of the herd.