A method for monitoring an animal, comprising: orally administering a bolus to an animal, said bolus including: at least one bolus sensor capable of generating a bolus sensor signal which varies based on change in at least one physiological parameter of said animal; a bolus memory element; a bolus processor communicatively coupled to said memory element; a bolus computer code contained in said memory element executable to encode said at least one bolus sensor signal generated by said at least one bolus sensor; a bolus communication signal generator capable of generating a bolus communication signal carrying encoded bolus sensor data; and a bolus communication signal receiver; securing a tag to an external surface of said animal: receiving with the tag said bolus communication signal carrying said encoded bolus sensor data; generating a tag first communication signal at a tag first communication signal frequency relaying bolus programming data from a remote processor to said bolus communication receiver for reprograming said bolus computer code; and generating a tag second communication signal at a tag second communication signal frequency carrying encoded bolus sensor data to a remote processor. orally administering a bolus to an animal, said bolus including: at least one bolus sensor capable of generating a bolus sensor signal which varies based on change in at least one physiological parameter of said animal; a bolus memory element; a bolus processor communicatively coupled to said memory element; a bolus computer code contained in said memory element executable to encode said at least one bolus sensor signal generated by said at least one bolus sensor; a bolus communication signal generator capable of generating a bolus communication signal carrying encoded bolus sensor data; and at least one bolus sensor capable of generating a bolus sensor signal which varies based on change in at least one physiological parameter of said animal; a bolus memory element; a bolus processor communicatively coupled to said memory element; a bolus computer code contained in said memory element executable to encode said at least one bolus sensor signal generated by said at least one bolus sensor; a bolus communication signal generator capable of generating a bolus communication signal carrying encoded bolus sensor data; and a bolus communication signal receiver; securing a tag to an external surface of said animal: receiving with the tag said bolus communication signal carrying said encoded bolus sensor data; generating a tag first communication signal at a tag first communication signal frequency relaying bolus programming data from a remote processor to said bolus communication receiver for reprograming said bolus computer code; and generating a tag second communication signal at a tag second communication signal frequency carrying encoded bolus sensor data to a remote processor. receiving with the tag said bolus communication signal carrying said encoded bolus sensor data; generating a tag first communication signal at a tag first communication signal frequency relaying bolus programming data from a remote processor to said bolus communication receiver for reprograming said bolus computer code; and generating a tag second communication signal at a tag second communication signal frequency carrying encoded bolus sensor data to a remote processor.