Figure 2 shows the MLI trends from 1991 to 1997 for the breed and for the herds with the highest and lowest regressions of MLI on year. Interestingly, in 1992, the two herds and the breed all had an average MLI of 105. However, they diverged sharply after that point. By 1997, the breed average was 120. Application Performance testing of pigs and sows is just the first step in a herd's genetic program.
Genetic progress is made by using the resulting EPDs and indexes when making selection decisions.
Within-herd genetic trends give important information about a herd's improvement over time, and will tell how the herd has progressed compared to the breed as a whole. They allow a breeder to determine whether his selection program has been a success. Because of the large advantage of using high indexing maternal sires versus average or below average sires, it is important that commercial producers identify the highest overall individuals - and these individuals will most commonly be obtainable from herds with the higher rates of genetic progress.