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More than 30% of GB sheep flocks don’t know their barren ewe rate or are reporting a figure greater than 5% after lambing. The... One in three sheep flocks unaware of barren ewe rate

More than 30% of GB sheep flocks don’t know their barren ewe rate or are reporting a figure greater than 5% after lambing.

The finding follows an online survey of 966 sheep flocks conducted by MSD Animal Health. Animal health livestock veterinary adviser Kat Baxter-Smith described the figure as concerning – and urged farmers to make amends.

“We’d advise any sheep farmer experiencing a barren ewe rate greater than 2% to discuss their flock health situation with their veterinary professional – and to rule out any potential underlying disease cause,” said Dr  Baxter-Smith.

Abortion causes

Some 27% of farmers reported a barren rate of 2-5% with only 42% meeting the accepted industry target of fewer than 2% ewes barren. Worryingly, one third of farmers said they did not investigate potential causes for abortions.

But it wasn’t all bad news. More than 45% of the farmers surveyed said they investigated abortions immediately in consultation with their vet. A further 21% tag any barren or aborting ewes for blood testing after lambing.

“This is what we would recommend,” said Dr Baxter Smith.

Ewe reproductive failure, neonatal lamb disease and mortality are the three biggest factors limiting better flock productivity  – with toxoplasmosis and enzootic abortion continuing to be significant causes of these unwanted flock heath issues.

Diagnostic scheme

MSD Animal Health has now launched its subsidised 2024 FlockCheck diagnostic scheme, which allows farmers in England, Scotland and Wales to blood test their flock for exposure to toxoplasmosis and enzootic abortion (EAE).

All farmers have to do is ask their veterinary professional to take blood samples from six to eight aborted, unvaccinated ewes, or from barren ewes or ones that have produced weakly lambs.

“The blood test has proved to be an extremely useful flock diagnostic tool in terms of helping to identify the potential presence of any key underlying productivity limiting disease,” said Dr Baxter-Smith.

She added: “Experience has shown that the results certainly help vets and their farmer clients make more informed decisions about appropriate flock health measures.”

Annual FlockCheck blood test results consistently demonstrate that a significant proportion of the aborted ewes tested have been exposed to either toxoplasmosis or EAE – and sometimes both.

For example, 2023 blood test results from more than 3,700 ewes showed 77% of 526 sheep farms had been exposed to toxoplasmosis and 17% to EAE3; with 13% of farms showing evidence of exposure to both pathogens.

This is consistent with a recent analysis by experts at the Animal and Plant Health Agency who found that toxoplasmosis and EAE were the most common diagnoses of sheep abortion between 2002 and 2019.

Both these infectious causes of abortion can be responsible for reducing the number of lambs per ewes mated, which can increase workload and stress during lambing,” said Dr Kat Baxter-Smith.

Profit may also be reduced significantly, she stressed, but diligent checking could help improve a flock’s potential and overall economic performance. Sheep can become very easily infected by toxoplasmosis, for example.

Embryo loss

“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 barren ewes or weak, sickly live lambs.

“It is likely that almost all flocks in Great Britain have been in contact with this endemic parasite, which means all breeding sheep should be considered at risk.”

Sheep pick up the toxoplasma parasite from the environment and normal biosecurity measures are not enough to control the disease. The eggs can survive in the environment for over a year so steps should be taken to protect sheep.

“Fortunately, the disease can be controlled effectively by a simple vaccination regime. What’s more, the costs of a vaccination programme can be easily covered by a reduction in future flock barren and abortion rates.

“|In reality, every ewe should be vaccinated before she breeds because of the widespread disease threat and the significant financial losses.”