The meaning of anything in a dream is really based on what your association with it is, so you would need to ask yourself, "What does a pregnant horse make me think of? What does a goat remind me of? What does pregnancy make me think of?" You would go through each part of the dream and ask yourself what it reminds you of or makes you think of. When you do this, you will begin to see that your mind is talking to you in images and feelings. Dreams are often ways to work out our problems, or even to have feelings that we feel forbidden to have in waking life. One Jungian method of dream interpretation is to become every single thing in the dream and then tell what you are doing in the dream and what your purpose is. The feeling or mood of the dream can tell you a lot, too, and one question you can ask is, "What in my life feels like this?" All that being said, pregnancy can be seen as the potential for new life, hope, anything full of possibilities. A monkey can symbolize the infantile, childish side of the dreamer. A horse is symbolic of energy or power, and a goat is said to symbolize the dark side of human nature. But remember, these are only generalizations, and I would much more trust your associations with these images, and therefore your own personal meanings.