A farmer had a talking sheep dog.

He said to the dog 'see the valley down there ?'

In a gruff voice, the dog barked 'yus'

'Well', the farmer replied, 'it's full of sheep. Go down there and round them up'

'OK' came the barked response.

After about an hour, the farmer returned, to find his meadow full of sheep and his dog lying down calmly.

'Well done ' the farmer praised his dog. 'How many are there ?'

'Forty' the dog gruffed back.

'Forty ?' Asked the farmer, 'There were only 38 this morning '

The dog replied 'well, you asked me to round them up'