摘要:The Net Present Value Sire Summary Professional Package (NPVSS) is a microcomputer program designed for technical personnel to help dairy producers better manage investments in genetic improvement. NPVSS is written in C language, utilizes the MS-DOS operating system, and requires 256K of RAM. It is menu driven and includes parameter screens to define herd management characteristics of individual producers. Profit rankings of bulls can be generated to evaluate alternative: a) objective functions (selection policies for genetic merit in milk income and type scores), b) herd management performance factors (conception rate, calving interval, age at first calving), and c) economic factors (milk price, semen price, discount rate, planning horizon).