I started using the 1lt Pegasus flax oil on my dog recently. Seems to be working well. Much better coat on him. Dead hair comes off him easier too. 1lt lasted nearly 3 months. So this 5lt will last the year and works out a lot cheaper. There is a date label on the bottle too, stating a best before Aug 2014.
The 1lt seems a lighter oil, and he doesn't mind it much now. This 5lt is a bit darker, maybe a bit less refined, I'm not sure.
He eventually eats his food, so it's all good. If it's good enough for horses, it's good enough for doggies too!