Having more milk cows has been profitable for most dairy producers this year, according to USDA's October Livestock, Dairy & Poultry Outlook. But prices may trend lower next year as cow numbers and milk production increase, which is what USDA predicts for 2007 and 2008. The number of milk cows has steadily increased from the second quarter of 2006. Dairy herd replacement heifer prices have been high and a resumption of heifer imports from Canada could add modestly to the national herd by early 2008, according to USDA.