This ornament is known as nyangoletom, and is attached to the horns of a man's favourite bull. At his initiation, each boy chooses a bull, and maintains a special relationship with it until its death, composing songs, and hunting and raiding for it. A bone pendant of similar form is in the Smithsonian Museum (No. 83-3-13), attributed to the Toposa, who are said to loop the suspension thong on the object around the horns of their cattle, with the pendant resting on the animal's forehead.
John Mack has commented that amongst the Toposa, the markings on these pendants may duplicate the marks tattooed on the shoulder of the bull's owner ( pers. comm., 8th October 2004). See also A. Kronenberg, "The Longarim favourite Beast", Kush IX, pp 258-277.