Maddox Dairy in Riverdale, California. Artificial insemination. Maddox Dairy is currently home to 3500 milking cows, calves, heifers and bulls. The dairy is a "birth to milking operation", with four, double-12, pregnant herringbone-milking parlors, free stall barns, calf raising barn and calving facilities. The dairy does their own embryo transfer work and markets their genetics worldwide. The Maddox Dairy was honored in 2001 with the Distinguished Dairy Cattle Breeder award for being a "Visionary Holstein Breeder", having bred more than 330 Gold Medal Dams, 502 Excellent cows, and their advancements in gene research for the Dairy industry. .