Possible Clues:

• For the sound that's heard, the dog might not stand it at last
• Sheepdog wth ling nose and shaggy hair
• Sheepdog with long pointed muzzle
• Dogged, but sheepish (6)
• Sheep-herding dog
• A sheepdog
• See 2
• For the old king to be about fifty-one made him so dogged
• Border dog
• When the old king is about fifty-one he gets quite dogged