© ABCLambs abound on Bindi Murray's property at Woodanilling
Extreme cold weather conditions in southern New South Wales last week created a perfect storm of unfortunate events for some sheep producers, culminating in some significant livestock losses.

The Department of Primary Industries, at the Cowra Research Station, is conducting autopsies on an abnormally high number of lambs from its commercial lambing flock.

The national average for lambing mortality is 10 per cent in ewes with single lambs and 20 per cent for twins.

But researcher, Dr Gordon Refshauge, said the mortality rate in this instance is almost 40 per cent.

He said he had never seen a situation like it.

"The weather has been very unusual for the last week," he said.

"Historically, in all my experience here, I have seen maybe 2 per cent or 1 per cent of lambs dying from cold exposure here at the research station.

"So far we are at nearly 40 per cent.

"It's a significant change. It's quite anomalous."

The Department's commercial flock was in the middle of lambing last week, when cold, wet, and snowy weather hit.

There was deep snow in the region but not at the research station.

Dr Refshauge said the unfortunate event was providing a unique opportunity for researchers.

"It's very interesting actually seeing what effects this has had on the ewes and what signs we are seeing in the bodies of these lambs.

"It gives us an opportunity to look at the role that cold exposure has on cause of death."

Dr Refshauge explained that lambs do not always die of cold conditions alone and usually there are a number of factors contributing to a loss of lamb during cold weather.

He said death from cold exposure was not necessarily an animal welfare concern.

"The evidence that we have from publications coming from New Zealand, tell us that lambs that die from cold, go numb and drift off into a sleep," he said.

"It's considered not to be a welfare problem.

"Lambs that die from starvation however are a problem, because they are aware of their hunger.

"So for producers that need to address welfare, they need to ensure that they have adequate nutrition and that these producers continue to select for rearing ability."