Do not know about Zebu, but A couple of years ago I crossed fenced a 1.5 ac. pond that is 12 feet deep in the middle...In the summer when water level at it lowest , i ran a cross fence into into water about 6 feet deep..as the water rose ,i had split the pond in half, although the fence does not go all the way across...Well to my surprise , cows can swim , and young cows seam to swim quite well....The grass is aways greener on the other side...ALF
Cows can swim but most dont like to. they definitely dont like to get their heads wet so no they dont swim underwater for any extended amount of time. they will swim short distances or wade to get to greener grass.
Zebu (unlike other cows) have the ability to sweat so they dont like to get in the water much except to drink.
cattle can swim, but they don't like it. they can't put their head under water because if their ears get flooded, they might loose their balance (short equilibrial disorder) for a short period of time.