Today I bred an Okapi x Okapi unicorns, and the baby is a palmino. I looked at the parents pedigrees and there was no palaminos in their heredity.  Anyone have a good explanation?

Thanks!

It means that both of the parents must have Striped and Cream genes, and the baby ended up inherited double Cream. 

Striped has higher gene power, so if the pet has both genes, Striped always ends up as the dominant marking. That pair will only breed double Cream 25% of the time, rest will be Striped.

Thanks Zaltys!

NEW QUESTION!!! I bred Okapi x Okapi again and got a black zebra? What happend there?

Also I bred to pure black unicorns and got a Buck skin?!? I am so confused with color genes!!!

Thanks!

This has to do with the genetics. Pets have a dominant colour gene and a recessive one. The dominant is the one you see, the recessive gene just sits in the background not doing anything. When you breed your pet, there is an equal chance that either that dominant or the recessive gene are passed down to the baby. So the baby may never get the colour you see on your pet, but only the colour gene that was hidden. Now it depends what the other parent gave (again the other parent cn give their visible or the hidden gene), and from there it's decided which colour will be seen. 

I tried to explain the genetics of the game in my guide here: http://beastkeeper.com/thread/5218
I gave examples with brain gene, not colour, but colour works in essence the same way. 

Colour is slightly more complicated than any other gene, because the colour of the pet is put together out of two genes, the colour and the pattern gene. Okapi for example is a Bay colour and a Striped pattern gene (you can see this in the Skin Library here). Black Zebra is also Striped pattern but black colour. So both of the parents had hidden genes that weren't Bay, at least one of them is Black, which was passed down to your baby.  To understand how dominant and recessive is chosen, please refer to the guide I linked, I explained Power of genes in there too. 

It would make it easier if you worked with pets that have at least their colour genes researched, then you know what you might get out of any breeding. 

Thanks Timain, I understand a lot better now!