>> reporter: patty leonard's family has been farming in northern virginia for almost a century. she says non-dairy alternatives to milk are cutting into her livelihood. >> they're trying to imitate milk. and i think that says a lot. they're trying to be what milk already is. >> reporter: her beef is with plant-based products like almond and soy milk, a growing industry thich generated $1.4 billion this year and grew 54% over the last five years. dairy milk sales are down 11% for 2016. stat2 members of congress from dairy-producing states are urging the food and drug administration to enforce its existing definition of milk, which states, "it is obtained by the complete milking of one or more healthy cows." chris galen is with the milk producer's federation. >> in the case of milk, you're m tting vitamins "a" and "d," calcium and a whole lot of protein. you're not necessarily getting those things in a glass of imitation dairy milk.