Different retractors can be used for veterinary purposes. There is a balfour retractor that has three curved loops mounted on a bar. Each of the loops is individually operable. The pediatric size of the balfour retractor is used in procedures to get to the vocal cords when working on horses.
An interesting point, when balfour retractors are sold by online sources who do not have licensing from the FDA to sell surgical tools to be used on humans, the sites must state that the tool is meant for veterinary use.