Who's top dog, Kiwis or Aussies?

Some of our top farm dogs are taking on their Aussie counterparts in a competition to see who works hardest. The annual Cobber Working Dog Challenge has thrown down the gauntlet to include Kiwi canines for the first time. Central Otago shepherd Peter Aitken has entered his heading dog Spark, who joins fellow mainland mutts Trix and Pine in the quest for national pride. Peter talks to Kathryn, along with competition organiser Kellie Savage.