A computer-based system for providing up-to-date health histories of animals, for example, in a feedlot. The system includes indicia elements associated with each animal for identifying the animal and a data entry device coupled to a computer for reading the indicia elements to identify the animal to the computer. The data entry means also communicates to the computer treatment data comprising the animal's physical condition and any treatment administered to the animal. The computer is programmed to record the identity and associated treatment data and collect the data with previous data to provide the animal's health history. The system also displays the identified animal's prior health history at the animal's location for the operator's benefit, which location is typically an animal hospital remote from the computer's location. The system may include a second data entry device for determining the net amount of drugs taken for animal treatment from an inventory. The computer is programmed to compare the net amount taken against the amount administered in treatment as communicated by the first data entry device to determine a difference in the amounts.