Actually 'Boga' was the NAME of Obi-Wan's steed in ROTS.

From the ROTS script (a deleted scene of course):

109 INT. UTAPAU-CITY-DRAGON CORRAL-DAY

OBI-WAN makes his way through the city, looking up at the tenth level with electro-binoculars from his utility belt. He tries to figure out how he is going to get up there. He hears strange bellowing cries and he investigates.
He comes across a corral filled with about half a dozen DRAGON-LIKE LIZARDS. SEVERAL WRANGLERS are standing around.
OBI-WAN walks up to the WRANGLERS and uses the Force with his slight hand movements.

OBI-WAN: I need transportation.

WRANGLER: (subtitled, in native tongue) You need transportation.

OBI-WAN: Get it for me.

WRANGLER: (subtitled, in native tongue) I will get it for you.

One of the WRANGLERS turns to the others and chatters away in his strange tongue. OBI-WAN walks along the line of DRAGON/LIZARDS, checking out each one. He looks at their teeth, legs, etc. Finally he pats one on the neck.

OBI-WAN: This one.

The WRANGLER brings the chosen one over to him.

WRANGLER: Boga. She answers to Boga.

OBI-WAN: Good girl, Boga.

OBI-WAN swings onto the back of the LIZARD. The beast rears up and scurries outside to the edge of the sinkhole.