A LED luminaire for use in a livestock barn includes a base plate provided with at least one first LED arrangement configured to, in operation, emit light which simulates daylight lighting conditions. The first LED arrangement includes a plurality of LEDs of a first type, which has at least one peak wavelength in the wavelength range between 500 and 600 nm, and at least one LED of a second type, which is a blue LED with its peak wavelength in the wavelength range between 440 and 480 nm. The luminaire is provided with an optical system configured so that the intensity of light emitted by the LEDs is distributed according a distribution which has its peak intensity at an angle of more than zero degrees from the optical axis of the luminaire.
