The theft of 25 calves in the Waimate district has prompted fresh warnings for farmers to increase security and keep an eye on stock numbers.
A farmer on Sodwall Road in Otaio has reported the theft of five heifer and 20 bull calves, thought to have be stolen between November and 5 January.
Waimate Sergeant Mike Vanderheyden said the farmer was unaware the stock were missing until he counted heads in his yards.
"The calves weren't reported as stolen until the farmer had accounted for all his cattle - got them in and did a head count.
"We're focussing some enquiries on the description of a vehicle that has been seen in the area one night, being a white horse float, but we have no further description other than that.
"This is a vehicle that was seen by the dairy farmer concerned who raised suspicion at the time but didn't realise his calves were missing at that stage and when he's thinking back he cannot think of the purpose of that vehicle to be there. It may be unrelated, but that's the only lead we have at this time."
People are being urged to keep an eye out for suspicious behaviour including stock being moved at night, which is not normal, he said.
Mr Vanderheyden said it was likely more than one person was involved in the theft.
"The difficulty for anybody stealing cattle is obviously catching them to put them in the trailers ... they would have to be caught individually as small calves and man-handled into trailers. Possibly taken more than one person to do that," he said.
Sergeant Vanderheyden said the theft followed others in the wider Canterbury region.
In December last year, 36 cows worth $70,000 were stolen from a farm in the Ashburton area.