66% of UK sheep farms test positive for fertility-affecting parasite

Data taken from 375 UK sheep farms shows that 66.4% of units had one or more ewes testing positive for the parasite Toxoplasman gondii, which causes toxoplasmosis.

This is according to data presented by MSD Animal Health, based on the results from blood samples taken between February and June 2021, when the subsidised FlockCheck diagnostic service was available to vets.

Taxoplasmosis

Taxoplasmosis can be a significant factor in causing barreness or abortion in sheep and possibly a leading cause of these problems in UK ewes earlier this year, according to MSD livestock veterinary advisor Dr. Kat Baxtar-Smith.

Infected cats are one of the ways this parasite spreads to sheep. They shed toxoplasma eggs in their faeces and sheep become infected when they ingest these eggs from contaminated pasture, feed and water.

The disease is also zoonotic – meaning it can be passed to humans.

“Toxoplasmosis, in particular, remains a key cause of barrenness and abortion in UK sheep flocks,” explained Dr. Baxter-Smith.

Dr. Kat Baxter-Smith

 

“It also causes reabsorptions, mummified fetuses, stillbirths and weakly lambs, and as a result of the range of different disease pictures that can manifest, its impact on flock profits is often significantly underestimated.

“Toxoplasmosis is so widespread that the industry focus should be on preventing infection in breeding ewes and the best way to do that is to vaccinate replacements well before they go to the ram,” she said.

Signs of toxoplasmosis abortion

A clinical sign which is characteristic of toxoplasmosis abortion is the development of small white areas in the cotyledons (buttons) of the placenta.

These are caused by focal necrosis (death of cells) in areas of the placenta due to damage caused by multiplication of the Toxoplasma organism.

While these can be signs of infection, laboratory tests are needed for a proper diagnosis.