BVD Eradication
Why Is BVD Eradication So Important?
In 2022 BVD remains a globally very common and massively economically impactful disease on both dairy and beef herds. There are many physiological implications from BVD infection that translate to a loss in fertility and productivity. Although we are all familiar with the persistently infected (PI) calf and the effects that has on the individual and some of the reproductive issues BVD causes this is not the whole picture. For example failure to control BVD within a dairy herd could be costing up to 169 litres per cow per lactation. [1] Neil Shand, chief executive of the National Beef Association, estimated that a 100 cow suckler herd can lose £10,000 over 10 years when BVD virus is circulating within the herd.
The effects of BVD include:
- Reproductive effects on the calf such as abortion, persistent infection (PIs are formed when the dam is exposed to BVD from around 30-120 days of pregnancy), congenital deformities and seropositive calves.
- Reproductive effects on the cow including poor conception rate, early embryonic loss, prolonged calving interval.
- Growth retardation.
- Decreased milk production.
- Susceptibility to other diseases.
- Early culling.
In order to eradicate BVD in a herd each farm will need a specific and robust biosecurity plan, routine monitoring for disease, identification and removal of PIs if present and prevention of infection. A comprehensive vaccination protocol provides an insurance policy for those herds that are naïve and also protects previously infected herds that have adhered to a BVD eradication scheme and become free of the disease. Despite your own best efforts it is important to remember that the poor biosecurity and husbandry practices of others can unfortunately have a devastating impact on herds that are vulnerable.
Vaccination must be effective, protect the vulnerable foetus during pregnancy and be easy to implement to ensure correct usage thereby stimulating a comprehensive and robust immune response in vaccinated animals. Bovela® is a unique live vaccine that is modified by the deletion of two genes from the BVD virus that would usually enable wild virus to evade the host’s immune system. This means an effective and protective immune response to BVD occurs without causing disease. As a live vaccine only one shot is required as a primary course and this just then needs boosting on an annual basis. This single injection not only induces excellent immunity without the impact of natural virus but also provides 12 months of foetal protection which is absolutely essential to stop the propagation of the virus within a herd. Although previous studies have already established that milk production is reduced in BVD outbreaks it is also important to consider the effect on production in herds where BVD is endemic and how vaccination may help them. The Advance study[2] compared cows vaccinated with Bovela® to co-habiting non-vaccinated cows within several commercial herds that were known to be endemically infected with BVD. The compounded gain in milk production was found to be between 57.4 and 181.7 litres per cow per lactation which was generally observed during early lactation (8-102 DIM).
In the UK different eradication schemes have been implemented in each country in an effort to control BVD. Whilst Scotland and Northern Ireland’s BVD schemes are compulsory, Wales ‘s Gwaredu programme is currently voluntary although there is a legislative proposal for the future and BVD Free England also currently remains voluntary. In spring 2022 in England it is notable that, as part of the new Animal Health and Welfare Pathway, BVD has been highlighted as one of the areas that unding will become available for.
Each scheme also differs in testing, surveillance, requirements to be considered BVD free and ongoing participation and monitoring. Several important factors must be established or addressed in order to make any eradication scheme successful.
- Farmers must be engaged with a scheme and this uptake varies depending on whether or not the scheme is compulsory.
- Vet-led schemes increase the speed and breadth of uptake.
- More alignment is needed in the different sectors of the cattle industry.
- PIs must be removed- according to the National BVD Survey 2021 some producers are still attempting to rear these animals- this is without doubt a huge barrier to eradication and makes little economical or welfare sense. A PI is essentially a virus producing machine shedding millions of infectious virus particles daily and perpetuating the vicious circle of infection and PI calf production within the herd.
In summary close co-operation between the various schemes, the farming industry and vets is the key to successful management and eradication of BVD in British herds.
Bovela® lyophilisate and solvent for suspension for injection for cattle contains modified live BVDV-1, non-cytopathic parent strain KE-9 and modified live BVDV-2, non-cytopathic parent strain NY-93. UK: POM-V. Advice should be sought from the prescriber. Further information available in the SPC or from Boehringer Ingelheim Animal Health UK Ltd., RG12 8YS, UK. Tel: 01344 746957. Email:vetenquiries@boehringer-ingelheim.com. Bovela® is a registered trademark of Boehringer Ingelheim Vetmedica GmbH, used under licence ©2022 Boehringer Ingelheim Animal Health UK Ltd. All rights reserved. Date of preparation: Jan 2022. UI-BOV-0012-2022. Use Medicines Responsibly.
[1] Fourichon et al. (2005) Quantification of economic losses consecutive to infection of a dairy herd with bovine viral diarrhoea virus. Prev Vet Med. 72: 177–181
[2] Schmitt–van de Leemput E, Metcalfe LVA, Caldow G, Walz PH, Guidarini C (2020) Comparison of milk production of dairy cows vaccinated with a live double deleted BVDV vaccine and non-vaccinated dairy cows cohabitating in commercial herds endemically infected with BVD virus.
- 1st March 2022
