If you keep sheep you should assume your flock has been exposed to the parasite that causes toxoplasmosis and aim to protect ewes well before they go to the ram later this year.

Toxoplasma gondii is now the world’s most common parasite and it’s been estimated that over 90% of sheep flocks in Great Britain are exposed to it. If you are not already vaccinating against toxoplasmosis it is probably only a matter of time before new ewes succumb to an infection, so you should plan ahead accordingly.

Certainly, if you had more than 2% of your flock aborting during the lambing season you should ask us to investigate. Now is the time to work out what caused this year’s problems with a view to avoiding similar next year. However, your primary focus should be on preventing infection in pregnant ewes in the first place, and the best way to do that is to vaccinate replacement ewes well before they go to the ram.

The complex lifecycle of the parasite presents significant disease management challenges to sheep producers. The sheer volume of infectious oocysts produced by
the parasite and their resistance to destruction leads to widespread environmental contamination: this is one of the main reasons why toxoplasmosis is so prevalent in GB flocks.

Sheep are very vulnerable to picking up the Toxoplasma gondii from the environment, so normal biosecurity measures are not enough to control the disease. Fortunately, toxoplasmosis can be controlled effectively by a simple vaccination regime. What’s more, an investment in vaccination will payback handsomely by a reduction in future flock barren and abortion rates. The clear industry advice now is that every ewe should have been vaccinated before it breeds. After two years, a single repeat dose can be given at least three weeks prior to mating. However, most ewes are only vaccinated once during a breeding life time as natural boosting occurs, so one dose may protect all lamb crops in the ewe’s lifetime.

All breeding females should be vaccinated any time between four months and three weeks before tupping. This gives a wide window of opportunity prior to the typical autumn breeding season, so it makes sense to schedule this crucial intervention as soon as possible, alongside other routine summer procedures.

If you experienced abortions or weakly lambs during the lambing season, please contact us for advice and we can investigate. For further information, please call the practice.