Is homeowner liable if his dog bites a person on his property when the person is breaking up dog fight between his dog & theirs

Under Oregon law, you may claim "economic damages" (e.g., medical bills, wage loss) arising from the bite. See ORS 31.360. If the dog who bit had a known vicious or dangerous propensity to inflict similar injuries to those you sustained, then the owner may also be strictly liable for all damages, including pain and suffering. If the owner were negligent in ineffectively controlling the attacking dog, then you should be able to recover economic and noneconomic (i.e., emotional distress, pain/suffering). However, there is an argument that you provoked your own injury or assumed the risk of harm or were contributorily negligent in failing to control the other dog (if you owned either). Which dog instigated the fight, did you own either dog in the fracas, and was their reasonable necessity to disengage the dogs are questions a court may ask.

Although I would not rule out the possibility of a claim without knowing all the details, since it took place on the dog owner's property, and your dog was involved in the fight, it may be questionable whether there is any fault on the part of the owner of the other dog. You might want to discuss all the details with a personal injury attorney.