The Dairy Club is a very active club of the COS Farm. The Dairy club supports the COS Dairy classes by hosting an annual Breakfast and Dairy Show every fall, along with showing heifers at the Big Fresno Fair. The club also takes an active role in the Freshman Field day by providing group leaders and cattle for judging.

This club recently built a new ice cream booth for the Farm Show 2001, which serves as the clubs largest fundraiser by selling over 360 gallons of Superior Dairy Ice Cream in 3 days each year. The dairy club also has a close ties with the South San Joaquin Holstein Assn. and has helped judge many contest for local 4-H groups.