Method and apparatus for indicating the onset of parturition

Apparatus for indicating at a distance the onset of parturition in animals comprising:

• a radio transmitter and a source of electrical power adapted to be secured to the pre-parturient animal at a position some distance from the vaginal orifice of said animal;
• a rupturable assembly adapted to be mounted across the vaginal orifice of the pre-parturient animal and having a preferred rupture line so that when the vaginal orifice distends during the onset of parturition the assembly ruptures along the preferred rupture line;
• connecting means for connecting the transmitter to the source of electrical power, said means including a switch disposed intermediate the transmitter and the source of electrical power which switch when closed completes a circuit therebetween, thereby causing power to be supplied to the transmitter, said switch being secured to the rupturable assembly on one side of the preferred rupture line;
• means for preventing the switch from completing a circuit between the transmitter and the source of electrical power while the rupturable assembly is unruptured, said preventing means being secured to the rupturable assembly adjacent the switch but on the opposite side of the preferred rupture line from the switch, the state of said switch except when it is proximate said preventing means being such as to complete the circuit between the transmitter and the source of electrical power, whereby at the onset of parturition the rupturable assembly ruptures, separating the switch from the preventing means, thereby completing a circuit between the transmitter and the source of electrical power, causing the transmitter to transmit a radio signal indicative of the onset of parturition.