Calves born to cows fed a protein supplement during late pregnancy have greater production characteristics compared to calves from cows not supplemented, despite similar birth weights. Our hypothesis was that cows receiving protein supplement during late gestation would have greater mammary gland blood flow allowing for enhanced lactation. Mammary gland hemodynamics were recorded during late gestation. While protein supplementation did not alter the blood flow to the mammary gland, this data demonstrates that mammary gland blood flow can be monitored during late pregnancy.