Sheep farmers are being advised to vaccinate ewes to protect flocks from damaging ‘abortion storms’ and an increased barren percentage which can dramatically reduce flock productivity.
Outbreaks of toxoplasmosis and enzootic abortion occur on farms every year, hitting finances and landing farmers with weeks of stress.
Together toxoplasmosis and enzootic abortion account for 70 per cent of sheep abortions in the UK.
Paragon farm vet Rhys Hopkins says: “Enzo and toxo are very common. So far this year we have diagnosed eight farms in north Cumbria with one or other, or both.
“We see farmers going through abortion storms or sometimes finding lots of ewes didn’t get in lamb.
“Last year one client had 20 or 30 ewes abort, and we easily see flocks where 20 percent of ewes can abort.”
There are effective vaccines against both conditions. But farmers should act soon as ewes must be vaccinated a minimum of four weeks before going to the tup, says Rhys.
Paragon Veterinary Group is promoting FlockCheck, a scheme run by MSD Animal Health, which offers farmers free tests on eight blood samples to detect whether either toxo or enzo are present in their flocks.
Vaccination costs are around £7 per ewe says Rhys. “That is a very good investment compared with the cost of keeping a ewe for the winter only for her to abort her lambs so you get no return.”
Enzootic abortion is caused by bacteria which are spread from ewe to ewe in infected afterbirth, on lambs, and in vaginal discharge for up to three weeks after lambing.
Aborted ewes must be isolated, and all birthing materials destroyed and pens cleaned.
Once a ewe has aborted she generally develops immunity. But enzootic abortion is highly infectious and spreads to other ewes on the farm causing them to abort the next year, so persisting from lambing to lambing, says Rhys.
“It can cause massive abortion storms. We can see people with 20 to 50 per cent of ewes aborting and they are late term abortions with very little indication beforehand.
“It can be quite overwhelming and containing an outbreak can be quite hard,” said Rhys.
“Flock mates which become newly infected look healthy, but the organism remains dormant in them and will usually cause them to abort the next year.
“Even fostering ewe lambs onto aborted ewes can be a risk as it is likely that lamb will become infected and could go onto abort in future,” he said.
“There’s a lot of work involved, and it can be quite soul destroying for farmers. Every time they go out to the shed they don’t know what they are going to see.
“It is heart breaking when they have done all the hard work for 12 months and they are on the home stretch and then they can sometimes have more dead lambs than live ones.”
Toxoplasmosis, caused by a parasite primarily spread in cat faeces, causes both abortion and an increased barren percentage.
“Once it’s on your farm there’s not many control options other than vaccination” said Rhys.
“We have had a flock this year that was at 10 per cent of ewes empty and the blood tests showed positive for toxo. Carrying 10 per cent of your ewes all winter to find out they are empty can be quite a financial burden.
“If ewes do get toxo they subsequently become immune, but the worry is if the toxo is on the farm anything naïve which picks it up will then go through the cycle, so replacements coming through are at risk of infection.”
Enzootic abortion and toxoplasmosis are also dangerous for pregnant women and people who are immune suppressed.
“The zoonotic risk is very high and pregnant women shouldn’t be in contact with sheep,” said Rhys.
Farmers can either vaccinate their whole flock in one go or spread the cost by vaccinating replacement animals every year acknowledging that it will take a few years to get the whole flock vaccinated.
“We find the FlockCheck scheme worthwhile, it has helped us diagnose a lot of farms with underlying toxo and enzo problems,” he said.
Paul Coates of Barrock End Farm, Armathwaite, now vaccinates all his replacement ewes after experiencing an abortion outbreak three years ago.
Paul runs a mixed farm which includes beef, arable and 1,200 lambing ewes made up of English, Cheviot and Scotch mules. He buys in 150 to 200 replacements every year.
Paul says: “We first started to see the signs in the gimmer lambs. We were getting to about 10 days prior to lambing, and we’d get a big lamb plus a runty lamb or a dead one as well. Of about 75 gimmer lambs that went to the tup, 25 aborted.
“It was a bit devastating and disheartening. You have done a year’s work and have put everything into the sheep - other vaccines, minerals, and you’ve kept them healthy - and two weeks prior to lambing you start losing them.”
Blood tests revealed toxoplasmosis, but the experience convinced Paul to vaccinate against both toxo and enzootic abortion every year.
“The toxo caused a big financial hit and you don’t feel the effect until the following year when you have lost the sales of those lambs,” says Paul.
“Now, basically everything we buy in, whether gimmer or shearling, is injected against enzo and toxo.
“It isn’t a cheap process but in the long term the benefits outweigh the cost – basically you can’t afford not to.”