The present invention relates to a livestock managment apparatus using a livestock temperature sensing device, and more particularly, to a livestock temperature sensing device having a built-in temperature sensor that can sense the temperature of livestock without having to exchange or replace the livestock temperature sensing device once the device is attached to the body of an animal even when the animal grows. The present invention further relates to a system and method using the livestock temperature sensing device for diagnosing diseases in the livestock, wherein the system has a communication device capable of transmitting the results of the sensed temperature and transmitting disease information to a terminal of a caretaker when the temperature of the animal rises above a reference temperature so as to enable a remotely-located manager to easily determine the state of health of the livestock. According to the present invention, the livestock temperature sensing device consists of: a temperature sensor a livestock body penetrating portion a temperature sensing body having a temperature information transmitting terminal and a temperature sensing body fixing means for fixing the temperature sensing body to the livestock. In the livestock temperature sensing device, the temperature sensing body consists of at least two temperature sensors on the bottom thereof so as to perform a temperature-correction function according to changes in body temperature and outdoor temperature, and the temperature sensing body fixing means consists of: a support plate a resilient portion a resilient portion support plate and a temperature sensing body coupling portion, and a GPS module is selectively contained in the temperature sensing body. The system of the present invention further consists of: a portable communication device for receiving the temperature information transmitted from the temperature sensing body, and including a display unit and software for analyzing, interpret
