SAC Consulting

Handling cows and calves on summer pastures can be both difficult and labour-intensive compared to working with housed stock.  In addition, handling cows and calves during the mating period can compromise fertility – at best leaving big gaps in next year's calving pattern and at worst resulting in more barren cows. 

These problems may be avoided or minimised by vaccinating as many calves as possible before turnout.  The youngest age at which calves can be vaccinated will depend upon which of the three BTV8 vaccines currently available is used.  Farmers are advised to discuss these choices with their own veterinary surgeons as soon as possible.

With all bottles of vaccine required to be used within 8 hours of opening, calves may have to be vaccinated in batches, rather than the ideal situation of them all being inoculated at the same time.  Whether this is possible will depend upon the length of the calving period, and hence the range of calf ages within the herd.  The difference in range of calf ages that can be treated on a single vaccination date is approximately 3 or 4 months, again dependent on which vaccine in used. 

There may however be an advantage in vaccinating calves in batches.  One good reason to do this would be to get maximum protection from the vaccine by ensuring that as many of the calves as possible are fully protected before the peak midge season arrives in July to September.

Another reason could be to synchronise vaccination with other routine handlings of the herd, or perhaps to vaccinate as many calves as possible while they are still housed to avoid having to handle them at grass. 

Later born calves could be vaccinated when the herd is being routinely handled e.g. while being sorted out ready for mating, or when groups are handled to change over bulls etc.

Unless it is absolutely necessary, things to avoid are –

• Combining vaccination with dehorning/castration
• Vaccinating in the autumn when calves are being weaned/housed and are susceptible to pneumonia
• Specifically handling groups just to vaccinate calves during the mating period
• To delay vaccination until the main bluetongue risk period (June to October) is over

Acknowledgement

SAC is part-funded by the Scottish Government as part of its Public Good Veterinary Advisory Service.