Abstract: A device for detecting the onset of parturition of a pregnant animal which comprises a thin, electrically conducting wire passing through the left and right sides of the animal's vulva region so that a middle portion of the wire lies across the vaginal orifice of the animal. Two stoppers are fixedly mounted on the two end portions of the thin wire and positioned so as to cause, upon separation of the left and right sides of the animal's vulva region at the onset of parturition of the animal, a tensile stress into a central portion of the thin, electrically conducting wire defined between the two stoppers and including the wire middle portion lying across the vaginal orifice, which tensile stress breaking this central portion. A switching unit connected to the two end portions of the thin, electrically conducting wire detects breaking of the wire central portion to thereby detect the onset of parturition of the animal.