New research by Teagasc (Roscommon/Longford) has found that some ‘iceberg diseases’ are leading to thin ewes in visibly healthy flocks.
The information was presented on the 2025 Teagasc spring sheep webinar, where they showcased a survey of 104 thin ewes over 60 flocks in the region.
The five main 'iceberg diseases' in sheep in Ireland are maedi visna, caseous lymphadenitis, ovine pulmonary adenomatosis (OPA or Jaagsiekte), pseudotuberculosis (Johne’s disease) and border disease.
Seamus Fagan from the Department of Agriculture’s Regional Veterinary Lab (RVL) in Athlone said these diseases can easily go undetected.
“Any iceberg, only a 10th of it is above the water. By the time you see these diseases on your farm, there’s a lot of damage done and a lot of the damage is in sheep that you don’t know are infected.
“It’s causing other problems like the parasitism; it’s driving up the infectious pressure on your farm.”
Survey
The main culprit for thin sheep were parasitic worms which appeared in 51% of sheep. Meanwhile, 17.3% of ewes examined were found to have teeth problems.
However, the survey also found that between 5% and 8.3% of the flocks had at least one sheep that was positive with an iceberg disease.
Post mortem check for OPA/Jaagsiekte.
“It’s not a huge percentage, but it is plenty high enough for us to be worried that the potential for spread is definitely high,” added Fagan.
“The same if you’re buying in sheep, you can take it that you’ve a one in 10 chance of buying [a disease] in.”
Prevention
Fagan said that the best way to prevent these diseases is to keep lambing sheds clean and healthy, good animal nutrition and body condition, plus biosecurity or minimising bacteria spread.
Fagan also suggested marking any sheep with bad teeth problems for culling because they can become sources for other diseases.
“When I say cull them as quick as possible, most times you’re talking about at the end of the lambing cycle when they’ve been weaned,” he said.
“Pull out your thin ones, give them a bit of extra something, but if after a month you think that some of them aren’t responding, then you need to figure out why. If you can’t, you need to get rid of them.”
Read more
Funding call for proposals to promote organic sector
Sheep Management: ewe hoggets, sheep census and hill sheep conference
Programme announced for Teagasc Hill Sheep Conference
Teeth issues significant cause of thin ewes
New research by Teagasc (Roscommon/Longford) has found that some ‘iceberg diseases’ are leading to thin ewes in visibly healthy flocks.
The information was presented on the 2025 Teagasc spring sheep webinar, where they showcased a survey of 104 thin ewes over 60 flocks in the region.
The five main 'iceberg diseases' in sheep in Ireland are maedi visna, caseous lymphadenitis, ovine pulmonary adenomatosis (OPA or Jaagsiekte), pseudotuberculosis (Johne’s disease) and border disease.
Seamus Fagan from the Department of Agriculture’s Regional Veterinary Lab (RVL) in Athlone said these diseases can easily go undetected.
“Any iceberg, only a 10th of it is above the water. By the time you see these diseases on your farm, there’s a lot of damage done and a lot of the damage is in sheep that you don’t know are infected.
“It’s causing other problems like the parasitism; it’s driving up the infectious pressure on your farm.”
Survey
The main culprit for thin sheep were parasitic worms which appeared in 51% of sheep. Meanwhile, 17.3% of ewes examined were found to have teeth problems.
However, the survey also found that between 5% and 8.3% of the flocks had at least one sheep that was positive with an iceberg disease.
Post mortem check for OPA/Jaagsiekte.
“It’s not a huge percentage, but it is plenty high enough for us to be worried that the potential for spread is definitely high,” added Fagan.
“The same if you’re buying in sheep, you can take it that you’ve a one in 10 chance of buying [a disease] in.”
Prevention
Fagan said that the best way to prevent these diseases is to keep lambing sheds clean and healthy, good animal nutrition and body condition, plus biosecurity or minimising bacteria spread.
Fagan also suggested marking any sheep with bad teeth problems for culling because they can become sources for other diseases.
“When I say cull them as quick as possible, most times you’re talking about at the end of the lambing cycle when they’ve been weaned,” he said.
“Pull out your thin ones, give them a bit of extra something, but if after a month you think that some of them aren’t responding, then you need to figure out why. If you can’t, you need to get rid of them.”
Read more
Funding call for proposals to promote organic sector
Sheep Management: ewe hoggets, sheep census and hill sheep conference
Programme announced for Teagasc Hill Sheep Conference
Teeth issues significant cause of thin ewes
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