The largest exported U.S. dairy product by total volume is ________.

The largest exported U.S. dairy product by total volume is indeed dry whey. This is primarily due to the significant demand for whey protein in various markets, particularly in the food and nutrition sectors, including sports nutrition and infant formula. Dry whey is a byproduct of cheese production and is processed to remove moisture, which allows for easier transport and longer shelf life. The growing global trend towards health and fitness has fueled demand for protein-rich products, leading to a high volume of dry whey exports.

In comparison, while cheddar cheese is popular and widely exported, its volume does not surpass that of dry whey. Whole milk and butter also have their markets but are not exported in the same quantities as dry whey. Dry whey's unique position as an ingredient in various food products and its appeal in protein supplementation largely contribute to its status as the leading dairy export by volume.