The male collie-cross, who has been named Leo, was left in a shed at Muirlaught Farm in Saltcoats, says the Scottish SPCA.
A worker at the farm discovered the dog who was said to be "very frightened".
The dog is now being cared for at the SSPCA Glasgow Animal Rescue and Rehoming Centre in Cardonald.
Inspector Kerry Kirkpatrick said: "Leo was tied to a metal barrel by his lead and he was very frightened. The person who found him, on January 2, had been working in the shed until 11.30am before leaving for an hour.
"When they returned at 12.30pm they discovered Leo, so we know he was dumped during this time.
"Leo is a really nervous boy but he's in good condition.
"We're keen to find out who abandoned him and why."
SSPCA inspectors are also trying to trace the owners of an adventurous cat who took a 80-mile road trip in the back of 45ft refrigerated lorry.
The two-year-old female moggy wandered into the HGV when it was being filled at Yearsley's yard on Belgrave Street, Bellshill, North Lanarkshire on New Year's Day.
The driver, Derek Purdom, then made his way to Dundee where the lorry was unloaded and the unexpected cargo was discovered.
Mr Purdom fed, watered and cared for the cat until he could take her to the charity's Hamilton centre.
Lorraine Alba, assistant manager at the centre, said: "It's very likely she has simply wandered off from home and got herself in a spot of bother."
If Bellzie's owners cannot be found, the SSPCA will find her a new home.
If you recognise Bellzie or would like to offer a home to Leo, call the SSPCA Animal Helpline on 03000 999 999.