Farmers are being urged to ensure their sheep have electronic identification tags and up-to-date records after the theft of a flock.
Police said 64 ewes and lambs were believed to have been taken from land near the Halloon Roundabout between St Columb and Indian Queens, in Cornwall, is between 15:00-21:50 BST on Saturday.
Most of the stolen livestock were Texel-cross-Roussin sheep, while a small number of Poll Dorsets and North Country Mules were also taken, officers said.
They want to hear from anyone who saw "suspicious activity, including vehicles such as livestock trailers or lorries, or anyone gathering or moving sheep" or a blue hatchback car reported to have been in the area.
'Visible identification'
PC Lucy Wyatt, rural affairs officer for the force, said: "The theft of livestock can have a significant financial and emotional impact on farming families and rural businesses."
She encouraged livestock owners to review security measures and ensure all sheep had electronic identification tags and their records were up-to-date.
She also advised they use visible identification, such as unique spray markings or flock-specific management tags and photograph valuable breeding stock, as well as securing equipment and vehicles.
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