Even thought it is a 2010, I'm the fourth owner. My understanding is Bobcat only gives a 12 month warranty. So the warranty is not a factor.
I'm looking for a common brand, something I'm able to find at Autozone, O'Reilly, Advanced auto, Walmart, etc. It is not convenient to seek out the Bobcat brand oil. And I don't believe for a second that there is anything special about Bobcat oil.
Does this oil have a type or grade or anything that defines it?
Here are some common offerings:
http://www.oreillyauto.com/site/c/detail/ORO1/74205/N0419.oap?ck=Search_hydraulic+oil_-1_2456&keyword=hydraulic+oil
http://www.tractorsupply.com//ProductDisplay?cm_vc=-10005&urlRequestType=Base&productId=212024&catalogId=10051&categoryId=&errorViewName=ProductDisplayErrorView&urlLangId=&langId=-1&top_category=&parent_category_rn=&storeId=10151
http://www.walmart.com/ip/Super-Tech-R-and-O-Hydraulic-Oil-2-Gallon/16795134