The average Holstein cow produces about 9 gallons or 75 pounds of milk per day. During each lactation period, which lasts about 305 days, one cow gives 2,674 gallons or 23,000 pounds of milk. During 2010, a single Wisconsin Holstein brought forth 72,170 pounds of milk.
As of 2014, Holsteins have the highest yield of any dairy cow breed in the United States. While the country has over 9 million dairy cows, about 90 percent are descended from Holsteins. Most of these cows give birth when they are between 23 and 26 months old, and this initiates milk production. When born, calves typically weigh between 80 and 100 pounds.