This is the heartbreaking moment a sheepdog in Mongolia tries to revive a ewe that has frozen to death in the field.

The sheepdog – from the Hulunbuir forest area in north-east Inner Mongolia, China – has become an online star after his owner Mr Chao began sharing footage of his work.

But in a sad new clip, the border collie -named Bian Mu – is seen desperately trying to resuscitate a sheep that died in the night in a snow-covered field.

In the footage, Bian Mu is seen nudging the sheep with his nose and even trying to warm the frozen sheep with his own body heat as he sits on the ewe.

The farmer said that the old sheep was a particular favourite of the dog, as they had grown up together and was very distressed when it realised something was wrong.

In other videos posted by his owner, the collie can be seen helping the farmer to push huge bales of hay into the field for the livestock to eat.

Bian Mu can be seen brushing away the snow from the food and pulling away the netting so that the sheep can eat the hay.

Mr Chao said his dog is incredibly intelligent and is always very enthusiastic about helping out with daily farming chores as the pair set out to the cattle pen in his truck.

And after all the work has been completed for the day, the two jump back inside the vehicle, where Mr Chao pats his helper on the head for a job well done before returning home.

Animal husbandry is the mainstay of the Mongolian economy, with 90 per cent of Mongolian livestock privately owned.