The Cow Days statue is fashioned after Gautama Buddha the spiritual leader and founder of the Buddhist religion.
Cow Days is a reference to Burro Days, a tradition celebrated in Fairplay, Colorado.
For the record, Cartman/Ming Li stays on the bull for 21.7 seconds.
The Cow Cult that forms is confronted by the FBI and then ultimately commits suicide when they forcibly take away the Cow Day clock. This is likely a parody of two topical high profile cults during the 1990s. The first would be the clash between Branch Davidian and the ATF and FBI in 1993. It was a 90 day stand-off when the religious cult refused to allow the ATF searched their Waco, Texas compound after they obtained a warrant based on weapons and child abuse allegations. The stand off ended violently with the FBI storming the compound in tanks and the Branch Davidian followers purposely lighting fires. Seventy four Davidian worshipers died in the conflict including their leader David Koresh. The incident is referred to as the Waco Siege. The other recent high profile cult incident involved the followers of Heaven's Gate a religious movement that believed that humanity was the product of UFO's and that the Earth was about to be "recycled". They reasoned that in order to survive this they needed to join with the comet Hale-Bopp during a period when it was brightest when viewed from Earth. To do this they all committed suicide on March 26, 1997. This would later be parodied in the episodes Two Guys Naked in a Hot Tub (1999) and Super Best Friends (2001).