Schmallenberg Disease 鈥� What to Watch for This Spring
Schmallenberg听disease is a viral disease听that is听spread by biting midges.听Transmission of the disease therefore occur during the midge active period, which is typically听April to November.听The virus can cause acute disease in听cattle听with fever,听diarrhoea听and milk drop.听The virus causes deformities in lambs and calves if听pregnant animals听are infected at the susceptible period of pregnancy (sheep 25-50 days, cattle 62-180 days).听Earlier infection may cause early embryo deaths and abortion, and thus high barren rates听
The virus was circulating in Scotland during the 2024听midge active period. Several cases of foetal abnormalities听were seen in the spring of 2025, and听plenty of evidence of exposure to听the听virus was found in听herds and flocks听in听large proportion听of the country.听听
Following infection, natural immunity develops which lasts听two to three听years.听This is why听we see waves of the disease a few years apart, although cases can certainly occur every year.听听
Be aware that the deformities can cause lambing or calving difficulties. This spring,听if something听doesn鈥檛听feel right,听consider that the lamb or calf might be deformed.听Call your vet in this instance.听听
The maps听below听show locations听of positive听Schmallenberg听Virus听(SBV)听cases in Scotland between January and July 2025.
Location of SBV antibody positive cases (red cattle, blue sheep). This indicates exposure to the virus.
Location of deformed foetuses confirmed to be due to SBV infection (red cattle, blue sheep).
Source:听Martin Tomlinson, University of Glasgow听
Preventing the disease is difficult as there is no听vaccine currently available in听the听UK. Some听preventative measures to consider include:听
- Shifting mating until later in the season to a time when midge pressure is lower could help reduce the risk of infection.听听
- Housing animals, use of midge netting, or use of insecticides (insect repellent) are not going to be completely successful, and not practical in most circumstances, but may be considered on a听case-by-case听basis, particularly for high value animals.听听
- Midges breed in wet conditions so听locating听muck heaps for example way from stock might help.听听
Alywen Jones, 伊人直播 Veterinary Investigation Officer, Alwyn.Jones@sruc.ac.uk
Posted by SAC Consulting on 16/03/2026
