I have yards and yards of African fabric - just like yours.
Toss it in the machine if you want.
I rarely prewash - only the solid hand-dyed (meaning non-commercial ones).
But it's fine if you do - this fabric is used to make the fabulous bright dresses for the ladies. It's 100% cotton.
Looks like Vlisco fabric to me --- Bartex might the technique or another fabric manufacturer. Vlisco is actually a Dutch company that makes fabric for the African market. Go figure.
Check out the latest fashion show here:
http://www.vlisco.com/