Mustard is a type of plant family that is identifiable by a pungent and sulfurous taste or odor. Most mustard's have flowers that are yellow with four petals shaped in a cross arrangement. This plant family includes many considered nuisance weeds, such as the yellow rocket, black mustard and peppergrass. Goats will eat these weeds, thus acting as a natural weed control.
Goats consume mustard weed without suffering harmful effects. These plants, however, can be dangerous to other animals, including cattle, horses, sheep and poultry. These types of animals may develop mustard weed toxicity if they eat a large amount of the plant in a short period of time. If you note primary signs of a mustard weed toxicity in an animal such as gastrointestinal irritation, oral irritation, head shaking, excessive salivation, vomiting and/or diarrhea, consult with your veterinarian.
Goats are browsers when eating and usually prefer brush and weeds such as mustard plants. They nibble from a variety of plants in order to take in proper nutrition necessary and avoid poisoning from eating too much of a toxic plant. Due to their eating habits, comprised of munching on a variety of vegetation, do not consider goats as your only solution to clearing away mustard weed.
Goats learn what to eat from their mothers. Most goats do not eat grass, but there are some who prefer it. If you want to purchase a goat that will eat brush and weeds, including mustards, confirm it was raised by a mother that ate brush and mustard weeds and avoided grass consumption.