2006 Colarado engine oil shows very little on dipstick when changed oil 600 miles ago?.This truck has never used oil before.?

make sure you don't use 20 or 30 weight oil that will burn off very quickly in an eleven year old truck , use 10-40 at least , preferably 10 -50 fully synthetic

Stick with the owners manual recommendations for grades and make sure the filter and drain plug are tight.

well it is now

Do a quick check of the PCV line and the breather hose. If either is wet with oil clean all of it. Once PCV valves get a little oil sucked up in them they tend to become oil magnets somehow and then force oil-wet air through the breather.

Did you change the oil or have some stoner without a GED in a jippy lube change it? If the latter it may never have been filled up properly - fill it back to the top of the range and check it again @600 miles to see if it is still using oil.

Search for a leak and check the inside of the exhaust pipe for black soot. Find a friendly mechanic and ask them.

Check to make sure the drain plug is tight and for oil leaks around the oil filter just in case the lube boy forgot to make sure the old oil filter gasket was still on the old oil filter and not stuck on the motor.

Top up the oil level. The distance between the lower and upper mark on the dipstick is one quart of oil.

So what you want us to do about it?

Refill it.

Check every week.

Check for obvious oil leaks.

If you need oil weekly, take to certified mechanics for actual results

Most likely a small leak