Any UK sheep producers that have experienced more than 2% of their flock aborting this year are being urged to blood test affected ewes for exposure to toxoplasmosis and enzootic abortion (EAE) – and do it before the end of July.
The established FlockCheck diagnostic service – which has been subsidised by MSD Animal Health for 10 years now and continues to be available from vets nationally – requires practitioners to take blood samples from six to eight aborted, unvaccinated ewes.
FlockCheck blood test results consistently show that the majority of aborted sheep tested have been exposed to either toxoplasmosis or EAE – and sometimes both – despite the availability of cost-effective vaccines.
According to MSD Animal Health technical manager John Atkinson MRCVS, both toxoplasmosis and EAE can be responsible for reducing the number of lambs per ewes mated, which can increase workload and stress during lambing. Profit may also be reduced significantly, he stresses, but using FlockCheck can help in improving a sheep flock’s potential and overall economic performance.
The latest VIDA data, compiled by the regional APHA and SAC Investigation and Disease Surveillance Centres across Great Britain, shows that toxoplasmosis and EAE account for 70-80% of diagnosed causes of abortion. Furthermore, toxoplasmosis is on the increase and has risen from 8% of diagnosable submissions in 2014 to 11% in 20151.
Toxoplasmosis, caused by infection with the Toxoplasma gondii parasite, does not just cause abortion. It is also the main infectious cause of early embryo loss in sheep and a very common cause of barrenness, abortion and weak lambs born alive. Research has shown that almost all flocks in Great Britain have been in contact with this highly successful worldwide parasite, which means all breeding sheep should be considered at risk.
Mr. Atkinson points out that one of the main reasons for such high levels of disease is that sheep can become infected very easily.
“Sheep pick up the toxoplasma parasite from the environment and so normal biosecurity measures are not enough to control the disease. Infected cats shed toxoplasma eggs in their faeces and sheep become infected when they ingest these eggs from contaminated pasture, feed and water. The eggs are tough and can survive in the environment for over a year, which means farmers need to take steps to protect their sheep.
“Fortunately, the disease can be controlled effectively by a simple vaccination regime. What’s more, the costs of a prevention programme can be easily covered by a reduction in future flock barren and abortion rates. Every ewe should have been vaccinated before it breeds because of the widespread disease threat and the significant financial losses,” he says.
The subsidised FlockCheck diagnostic service allows vets to identify whether toxoplasmosis or EAE (or both) are likely to have been involved in any aborted lamb losses. This aids the decision for (and identifies the potential value of) pre-tupping vaccination programmes with ENZOVAX® and TOXOVAX®.
Farmers interested in taking advantage of the subsidised FlockCheck diagnostic service and reducing the risk of lower productivity should contact their local practice as soon as possible. This year’s blood samples must be submitted by 31st July 2016.