As you are well aware, the process of selecting replacement heifers is very important in a commercial cow/calf operation. These females represent the future factory. Because puberty is related to weight, it is important that weaning weight be part of your selection criteria. To start, we would suggest culling the upper 1% of the heaviest and lightest 25%. The heaviest heifers at weaning may represent big, growthy heifers that may not fit your environment. Make the selection on actual weaning weight because that's the weight you will be using to develop a feeding program so that they reach puberty (about two-thirds of their mature weight) before the start of the breeding season. Then make selections on conformation (body type, feet, and legs) and apparent disposition. Of the heifers that are remaining, look at their dam. If their mother is old, meaning she has been part of the herd for many years, this is a heifer that you might consider keeping because her mother has been a productive part of the herd for many years and therefore must be adapted to the environment (forage resources, management, etc.). You might expect similar performance from her offspring.