Of the objective measurements recorded in the performance programs, some are used for EPD calculation, while others are not. When making breeding decisions, EPDs are important, but many other factors are important too. Anything less than totally accurate and complete performance recording reduces the relative accuracy of each animal's EPDs. Breeders have told me a certain animal's EPDs do not match its performance. In a few cases this can be expected.
Many genes influence an animal's performance.
By chance, an animal can receive an unusually superior or inferior set of genes from his parents. In most cases though, the reason an animal's EPD does not match his performance is because performance information was not submitted to AHA or that record was inaccurately recorded. In order to assure your performance measurements are used in the genetic analysis, measurements should be taken within the acceptable age range. For example, a weight taken when a calf is 60 days old cannot be used to calculate an adjusted 205-day weaning weight. The most important factor and one many breeders do not understand is contemporary groups.