My friend posted this cute video of her and the Border Collie Barney at herding. Barney is 13 years old deaf and half blind dog with liver issues. He met sheep for the first time in his life and see what came out 
The dog turned 5 years younger at least and was totally happy 
https://www.facebook.com/photo.php?v=788304241186625
The dog turned 5 years younger at least and was totally happy https://www.facebook.com/photo.php?v=788304241186625