FFA Veterinary Science CDE Practice Test

Which grass is known to produce cyanide and can be poisonous to animals?

1. Bermuda

2. Exhaustion

3. Fescue

4. Johnson Grass

The correct answer is: Johnson Grass

The correct answer is Johnson Grass, which is known for its potential to produce cyanide, making it toxic to animals. Johnson Grass, a perennial summer grass, can accumulate cyanogenic glycosides in certain conditions, particularly when it is stressed, such as during drought or when it is rapidly growing. When animals consume this grass, the glycosides can convert to cyanide in the digestive system, leading to symptoms of poisoning, which can be fatal. Other types of grass mentioned do not carry the same risk regarding cyanide production. For example, Bermuda grass is more commonly valued for its forage quality and does not exhibit cyanogenic properties. Fescue is known for its benefits in grazing but is not associated with cyanide toxicity. The term "Exhaustion" does not refer to a type of grass and thus does not apply to the context of this question. In summary, Johnson Grass is the well-documented species that poses a risk of cyanide poisoning in livestock, which is why it is the focus of this question.