The livestock shed has parallel rows of stanchions rising from a concrete base and a metal roof that is built in two halves that are separated by a central air gap. Each roof half has an inclined center strip defining one half of the gap edge. The roof portion is generally concave. The resulting shed is of correspondingly low profile while still exerting good ventilation. In capped versions, the gap is surmounted by a convex roof cap spaced above the gap in order to allow ventilation while excluding precipitation.