ABSTRACT
California and Wisconsin are the top two leading milk-producing states in the United States. In 2015, California produced 18.6 billion kg of milk that amounted to 19.6% of the total US milk supply, whereas Wisconsin contributed 13.9% of the US milk supply by producing 13.2 billion kg of milk (ERS-USDA, 2016). The California and Wisconsin-based dairy production and feeding systems are substantially different from each other. The California Production Systems (CPS) are characterized by fewer dairy farms but large herd size (1438 dairy farms with 1215 dairy cows/farm in 2015) and feeding strategies that rely heavily on purchased feed and by-products feeds. In contrast, the Wisconsin Production Systems (WPS) are characterized by a greater number of dairy farms with smaller herd size (9898 dairy farms with 129 dairy cows/farm in 2015) and feeding strategies that rely more on home-grown feed (Short, 2004; CDFA, 2015; NASS-USDA, 2016).
