A North Otago dairy farmer says he is in a state of disbelief after realising 60 rising 2-year Friesian heifers had been taken from his farm.
Russell Hurst, of Awamoko, said the animals, taken between the week before Christmas and New Year's Day, could be worth $100,000.
He and his staff went ''around and round the farm in circles'' double-checking the mobs on the 2500ha farm to make sure the animals had been stolen.
''It's just disbelief, really,'' Hurst said.
''Anger ... I think if we'd seen real evidence - a hole cut in a fence, maybe - but this is just disbelief at how they can vanish with almost no trace. There is no trace.
''You sort of suspect things, but then you have to do a lot of soul-searching and checking yourself to make sure you've got your facts right.
''It's one of those things - as I say, we've got 1000, so we've five mobs of that age group scattered around the farm, so we just wanted to make sure we hadn't miscounted or some had got out and got in with another mob.
''It's a big accusation to make that somebody's stolen 60 cows. If you say someone's flogged a cow that's not too bad, but 60 is a different story. I didn't want to go off half-cocked, you might say.''
The animals had just been mated and would have become first-year milking cows in August.
''Not only have we lost the animals, we lost the calves inside them, too,'' Hurst said.
The suspected theft occurred not on State Highway 83, which bordered the farm, but on one of the back roads.
Nevertheless, his farm was not in a remote area and somebody might have seen something.
The farm had had individual animals stolen before but not a theft on this scale.
''There's different scenarios. People could have been nibbling away at them, or it would have had to have been very organised with a portable yard or a very large truck - you could almost get that number in one of the big rigs that they have nowadays, but it would be pretty full.''
Sergeant Blair Corlet, of Oamaru, said inquiries were continuing.
-Oamaru police (03) 433-1400.