In addition, a user can restrict the number of sires by entering fewer sires than the total number of proven bulls, and the young bulls for progeny test enables them an equal chance to breed.
For bulls, culling was done based on the animal's age, taking into account three different groups: proven bulls, steers (progeny of young bulls selected for the progeny test), and ordinary bulls.
During the first 4 years of simulation, bull calves were used as a source for proven bulls.
However, they are to select Hanwoo proven bulls optimized under the varying environment in accordance with social and economic requirements for Hanwoo or changes in price structure.
Number of Hanwoo proven bulls by year Year '87 to'90 '91 to'95 '96 to '00 Head 85 94 89 Year '01 to '05 '06 to '10 2011 Total Head 84 109 20 481 Table 9.