A Central West producer has had three stillborn lambs, at the end of lambing, with goitres in lambs indicating there having been an iodine deficiency in the ewe during pregnancy.
Along with the goitres - a swollen thyroid gland caused by a lack of iodine - the lambs were slightly smaller than average but went to term.
Local Land Services veterinarian, Alicia Moses, attended the property at Grenfell where the stillbirths occurred and said there were a couple key reasons that could cause the iodine deficiency.
Sheep and goats get a lot of their minerals from ingesting soil, Dr Moses said, so in high rainfall areas where there's plenty of lush feed, the animals may not ingest enough soil and therefore iodine.
Dr Moses said the flock at the Grenfell property had been grazing on brassicas.
It was the first case of iodine deficiency the vet had seen from the most recent breeding season.
She said the Grenfell producer only picked up on the iodine deficiency due to the obvious goitres and that milder cases of the deficiency could be occurring in the region but weren't being detected.
While goitres are "the classical symptom of iodine deficiency", Dr Moses said, weaker lambs that couldn't tolerate cold weather, or possibly born with alopecia (hair loss), along with increased abortions were among other symptoms.
"Potentially there are other cases that are borderline where you may not be actually seeing the obvious goitre," Dr Moses said.
"You may be getting increased perinatal mortalities, but we don't know unless we do some testing and investigation - it could be a number of different things that could be quite similar."
Dr Moses said if a producer was seeing any symptoms, they should contact their veterinarian.
"I would say definitely if you're having any increased mortalities of lambs, talk to your local district vet or private vet to do an investigation because there are multiple things that could be causing it," she said.
"Unless we're getting the history and looking at the clinical pictures and maybe doing some testing, it can be difficult to differentiate."
Local Land Services advice said prevention on farms with a history of iodine deficiency included drenching pregnant ewes four and eight weeks before lambing with 280 milligrams of potassium iodide per ewe.
Dr Moses said it was best to speak to a vet first and before drenching was needed.
Salt licks containing potassium iodide was another prevention technique.
"They're not the be all and end all because it is up to the ewe to go voluntarily lick and consume that lick block, but it may help those marginal ones where you're not seeing that overwhelming iodine deficiency with the goitre in the stillborn lambs," she said.
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