text: A hero on his way to retrieve some of these animals gets so exhausted by the heat that he fires an arrow at Helios; unexpectedly, he is rewarded with a giant golden goblet.
full_question: A hero on his way to retrieve some of these animals gets so exhausted by the heat that he fires an arrow at Helios; unexpectedly, he is rewarded with a giant golden goblet. Eurytion and his two-headed dog Orthrus guard a large number of these animals owned by the three-headed giant Geryon and stolen by Heracles for his tenth labor. A tortoise shell is used to make the lyre as recompense for the theft of some of these animals by the infant Hermes. Hera sends both a stinging gadfly and a hundred-eyed watchman named Argus to torment one of these animals that is actually Zeus's lover, the nymph Io. For 10 points, name these milk-producing animals.
first_sentence: A hero on his way to retrieve some of these animals gets so exhausted by the heat that he fires an arrow at Helios; unexpectedly, he is rewarded with a giant golden goblet.
raw_answer: cow [or cattle; do not accept "bull"]