Schmallenberg virus (SBV) made headlines in 2011 when this new virus was first identified, and it appears that the disease may be re-emerging. Whilst it can cause milk drop and fever, its most profound effects are on the unborn foetus as it damages the brain and spinal cord and causes deformity of the legs, spine and head.
Cases were confirmed on the continent this Spring, and evidence has started to build closer to home. Within our practice, a September PD session found 11 of 22 heifers empty: all 11 were positive for SBV. Our local lab reports that they have had positive bloods from yearling cattle, providing further indication of SBV activity this year. One of our clients’ farms had two deformed calves delivered by caesarean on consecutive days; no tests were run but with hindsight these may have been Schmallenberg cases. We are seeing lower PD+ rates, and heifers which have been PDd in calf coming bulling having reabsorbed.
SBV is spread by midges and there is currently no vaccine, so the best advice is to be vigilant. Cows are likely to have some immunity, heifers less so; therefore it is younger stock which is most at risk. Don’t assume PD+ heifers will stay that way – consider repeat PDs and look for bulling – and be prepared for calving difficulties.
Contact AHPA if deformed calves are born as they may want to run tests on the brain and spinal cord in order to confirm the diagnosis.