On a farm (F), livestock animals (A) are pastured and to each livestock animal (A), a communications device (101) that measures the step count of the livestock animal (A) is attached. An estrus notifying apparatus (103) receives, via relay devices (102) installed on the farm (F), measurement result information indicating the step counts of the livestock animals (A) from the communications devices (101). The estrus notifying apparatus (103) determines from measurement results of the step counts of the livestock animals (A) from the communications devices (101), whether the livestock animals (A) indicate estrus. If a livestock animal (A) is determined as indicating estrus, the estrus notifying apparatus (103) determines whether another livestock animal (A) that is in estrus is near the livestock animal (A). If no other livestock animal (A) in estrus is present, the estrus notifying apparatus (103) determines the livestock animal (A) to be a livestock animal indicating estrus and transmits identification information of the livestock animal (A) to a client apparatus (104).
