The Ashburton farmers who had around 500 cows stolen will financially struggle to make ends meet in an unusual theft which has left farmers on edge.
Police are continuing their investigation into the incident, likely to have taken place over some time, and have taken statements.
They won't comment further on the case.
However, they and Federated Farmers says farmers should keep an eye out for suspicious behaviour and take precautions to stop further thefts.
Will Leferink, a spokesperson for the farm, says the cows' owners are "absolutely gutted" about the theft and embarrassed it took so long to discover.
He says they only realised the cows had gone missing because there was a surplus amount of feed and a fewer-than-expected number of calves.
"There were so many cows that needed to calve every day and there's normally a good record of that and it didn't match, so they started to wonder and counted the cows and found out pretty quickly," he says.
The farm had 1292 cows and at the last count on July 10, they were all accounted for.
Mr Leferink says the owners called police after they'd realised, but their response was "lacklustre" because officers have "got a lot on their plate".
The theft represented a loss of about 40 percent of their stock, and they'll be hard to replace.
"A lot of people, to support their cashflow because of low milk prices, have culled a lot of cows so there's not a lot of surplus cows around anymore."
Fewer cows means less income, but outgoing costs remain the same, Mr Leferink says.
The high-producing cows are estimated to be worth around $1500 each.
Federated Farmers mid-Canterbury president Michael Salvesen says there had been "one or two" thefts of cows last year but not to the same scale - previously there'd been around 30 or 40 go missing.
It's left the region's farmers more cautious.
"There've been one or two suspicious things going on so people are on high alert and quite concerned about who's floating around, especially at night time."
He'd heard of farmers taking extra precautions including padlocking their gates and cutting off gateways so there's only one main entrance to the farm.
"We're feeling for the farmers and their staff that are directly involved and disgusted people would go to those lengths to ruin people's livelihoods for themselves," he says.
Senior Sergeant Scott Banfield says farmers should be checking their boundaries and fence lines regularly.
He says it's unlikely the animals were taken all at once and said regardless of the property's size, stock numbers should ideally be checked once a week.
Snr Sgt Banfield says neighbours should take note of any stock movements, particularly if it's unusual for this time of year.
"If possible, make a note of any suspicious vehicle's registration number, and a description and direction of the vehicle and what it was carrying."
Photos of vehicles are also helpful for police, Snr Sgt Banfield says.
Anyone with information should call Canterbury Police on (03) 363 7400 and quote file number 160825/7150 or alternatively call Crimestoppers anonymously on 0800 555 111.