Barren Ewe Testing

Latest results from Intervet/Schering-Plough Animal Health’s annual Flock Check survey revealed that almost two-thirds of flocks tested were positive for toxoplasmosis. Yet a survey of farmers this summer showed that two-thirds don’t vaccinate for it.

This leaves flocks at risk of barrenness, abortions and the birth of sickly and weak lambs. These typical signs of toxoplasmosis were reported by farmers surveyed and suggests that ewes could have been infected while pregnant last year. Some 15% of the farmers had had lower scanning percentages than expected; 12% saw more abortions; while a further 15% said that they had seen weak and sickly lambs. Such losses easily erode performance and profitability.

Although sheep develop their own immunity to toxoplasmosis, particularly when infection occurs at any time other than pregnancy, it’s a risky policy, to hope that infection occurs when ewes are not in-lamb.

The scale of damage caused by the protozoa depends on the stage of pregnancy. In the first 60 days, the foetus is re-absorbed and the ewe appears barren. From 60 days, there is abortion in late pregnancy with mummified foetuses, stillbirths or weak and sickly lambs that often die.

The most reliable form of protection is using a live vaccine such as Toxovax®. This requires a one-off injection for the whole flock, after which only replacement females will need to be vaccinated.

Any flock with barren or abortion rates greater than 2% should investigate the cause. Talk to the practice about ordering supplies of Toxovax to protect your flock this winter.

Toxoplasmosis & Enzootic Abortion Testing

The program involves blood testing six barren ewes between 1st Jan to 31st March. 70% of flocks nationally are infected with Toxoplasmosis, both Toxoplasmosis and Enzootic Abortion are zoonoses i.e. diseases that can be transmitted to humans.
There are vaccines available for both diseases.

There is some money available from pharmaceutical companies to subsidise the laboratory teats – please contact us for details.

Additional testing available:

  • Copper
  • Cobalt
  • Selenium