The idea for an interactive vaccination calendar was in fact first developed two years ago by Jon Reader MRCVS (pictured right) from Synergy Farm Health. With input and funding from Boehringer, it has now been developed into an online tool which highlights times when animals may be at risk if immunity has waned, without sufficient boosting of immunity by vaccination.
The transmission of BVD is complex and protecting the foetus from the virus is at the heart of any control programme. The virus is passed from dam to foetus and, if this occurs in the first third of pregnancy and the foetus goes to term, a persistently infected (PI) calf will be born. These will then go on to shed virus throughout their lives, so infecting herdmates and the next generation of calves.
Jon said: "The timing of when a vaccine is given is critical to the development of an immune response, which will protect the unborn foetus.
"Working out when you want the dam to calve and then calculating back shows when either a primary course of BVD vaccine or a booster should be given but, get this wrong and you will end up with what is known as an 'immunity gap'.
"It is vital that both heifers and cows have maximum protection during the breeding period and in early pregnancy."
Boehringer says heifers must be fully protected before being served for the first time, and cows must have had immunity boosted before they are pregnant again. However, far too often heifers are adequately protected following an initial booster but given their age and date of service, do not receive further protection until they enter the adult herd.
Jon said: "If heifers calve just after the herd booster, then there is a very real possibility that they will go for two years without a booster, and be severely exposed when they become pregnant as a first lactation heifer."
"This is termed the immunity gap; a period when the animal is not protected from the virus at all. The aim should be to eliminate this period completely, so that there is no immunity gap."
Matt Yarnall from Boehringer said: "Each BVD vaccine has its own timing protocol stating when the primary course should be given, as well as subsequent booster timing and when cows should be served. Moreover, some of these are not straightforward to follow, especially for year-round calving herds."
"Anyone using the Bovela vaccine has peace of mind that the one dose primary course combined with flexible booster regime and 12 months’ proven duration of immunity minimises the immunity gap."
For more information, visit: makebvdhistory.co.uk.
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