
Both my dogs have raw liver as a regular ingredient of their raw diet. One dog would eat it raw from the off whereas the other wouldn't. For the second dog I would flash cook it for 10 seconds in the microwave and he ate it without hesitation. I gradually reduced the length of time it was cooked for and he is now happy to eat it raw.
When you first start to feed liver it is advisable to feed in small amounts and gradually increase the amount as your dog's digestive system becomes accustomed to it -helps to prevent Dire Rear. My dogs can now eat sizeable quantities of the stuff at one sitting without it having an adverse affect.
Can't remember which poster said it had upset their dog's stomach but I did note that they had fed a marrowbone at the same time - the marrow inside marrowbones can also cause upset tums so it could well have been this that caused the problem rather than the liver or maybe the combination of the dog having both items on the same day.