Determine the number of Holstein dairy cows needed to supply adequate milk to meet the US consumer demand if bST is used. 1. US human population is 330 million 2. Holstein dairy cow produces 23,000 lb of milk per year 3. The effect of bST on milk production is 10% 4. Use of bST starts at 9 weeks post-partum 5. Subtract 3,000 lb of milk form total amount (approximate amount produced before bST treatment starts) 6. Per capita U.S. consumption is 134lbs