The term Mooloo is a common nickname in New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 for things pertaining to the Waikato

Waikato

The Waikato Region is a local government region of the upper North Island of New Zealand. It covers the Waikato, Hauraki, Coromandel Peninsula, the northern King Country, much of the Taupo District, and parts of Rotorua District...

 region, most particularly the Waikato Rugby Team

Waikato Rugby Union

The Waikato Rugby Union is the official governing body of rugby union in the Waikato area in the North Island of New Zealand. Its senior representative team competes in the ITM Cup , and won the inaugural Air New Zealand Cup in 2006.Waikato Rugby Union was founded in 1921...

and its supporters, though it is likely that the term's use for the region in general pre-dates its use specifically for the rugby team.

The origin of the term comes from the sponsorship link between Mooloo Ice Cream Company and the Waikato Rugby Football Union. The abundance of dairy herds in the Waikato has seen the link between the term Mooloo and the region grow strong