Schmallenberg Antibody Positives in Dairy Herds
The RVLs have received a number of reports of milk drop syndrome in dairy herds this summer. A high rate of seropositivity to Schmallenberg virus (SBV) has been found in the samples submitted from some of these herds. In the SBV-seropositive cows, clinical signs have included milk drop, diarrhoea, pyrexia and apparent pregnancy loss, although not all clinical signs were present in all affected animals. Many of the seropositive animals had been born since 2018, which is when the virus is thought to have most recently circulated in Ireland. This indicates more recent re-emergence of the virus. Care must be taken in interpreting single serology results, as alone they are not diagnostic for SBV. However, in some of these herds the virus itself has been detected or very recent infection has been diagnosed using paired serology tests around the same time the clinical signs occurred, suggesting that SBV was responsible. Animal keepers should be vigilant for the clinical signs described and consult their veterinary practitioner for advice if they are seen.