What ever happens to baby horses?

When I was little my favorite book was called "What ever happens to baby horses?"
Every page would show a different baby horse coming from a different background. Some were born on farms, some in the circus, etc. Then at the end of the book it would show each of them as an adult horse performing their "profession." The circus baby would be in the circus, the farm baby would be doing manual labor, etc. The last page of the book was a shaggy draft horse as a baby growing up in a barn with a bunch of kids. He was my favorite. One horse was an Appaloosa and so it had spots on it. When I could barely talk I would point at it and say "cow." My dad would always correct me and say "no, its a horse that looks like a cow." So as I got older (and continued reading it every night) I would say, "looks like a cow!" It was my favorite book and I looked at it every night for years. Now I can compare it to humans and see how metaphorically it could be saying that people don't change. You're destined to end up like your parents. Where you come from stays with you.