Debt to income for mortgage

[Dyami Pike]

So I am looking into moving out of state. I own a home in Missouri and I'm planning on moving to Houston area. I've owned this house long enough that I can get another conventional or FHA low down payment, but I don't want to sell this house and I would want to rent it to keep building my net worth. The numbers work for it so I'm not concerned about renting it, but for a second mortgage I know they look at DTI ratio. Would my rental income counterbalance that? I don't really get how that works.