The correct answer to this open question is the following.
Although there are no options attached or further context, we can say the following. You did not mention the name of the emperor, but doing some research we can say you are referring to emperor Wudi.
What the Han emperor brought with him when he went for a ride were his Fergana Valley horses. I think he needed them to show the vast power he had and impress his enemies.
The Fargana horses were the pride of the emperor and came from modern-day Uzbekistan. These horses were infected and had hemorrhages. This was a sign of mysticism for the Emperor who thought that the horses had divine designs from the heavens and represented good luck for the emperor in his rides.