Nature, nurture, and vegetation management: Studies with sheep and goats

•The genetics and environment affect the consumption of invasive weeds by herbivores.•Percentage leafy spurge in animal diets was goats > fostered lambs > ewe reared lambs.•Sheep fostered on a doe ate half as much spurge as the doe’s biological offspring.•Goats spent less time grazing and had a lower bite rate than sheep.•Consumption of plants is limited by the animal’s ability to ameliorate aversive properties of plants.