Many individuals are predicting a "second green revolution" in agriculture from the introduction of growth stimulants into the livestock industries. An economy-wide approach is used to determine the affects on prices and quantities of introducing growth stimulants in the domestic dairy and pork industries. In general, the impacts are found to be much smaller than previous research focused at the sectoral level has suggested. Increases in the amount of lean meat per hog, which reduces processor demand, may actually lead to a reduction in pork production at the farm-level.