The lower score is neither the best nor the worst. It is the percentile score of where the animal is expected to be for that trait within the general population. It is up to you to decide where you want that score. Using height as an example, If you like them really tall, you might want an animal that scores in the lowest percentage, and if you like them short, you might want one in the highest. These numbers are used to bring more accuracy to the animals Epd's. They are considered equivalent to recording data from a certain number of offspring. That number varies depending on the trait. A new born calf will have epd's that are just an average of his parents. They can be far from accurate, since the animal may be more like one parent or another, or even some more distant relative. Over time, you can report that animals performance, and the performance of their offspring. This will gradually give you a more accurate look at what you can expect to be the performance of future offspring.
The Genetic profile, looks at that animals DNA and uses that to make a somewhat more accurate estimate of future performance. They have looked at the DNA of thousands of highly proven animals, and attempted to draw conclusions on what markers within their DNA are shared by bulls with common traits. When you run a genetic profile on an animal, they look at that DNA and try to find markers in common with the proven bulls. If for example, your animal shares many of the same markers as those of other animals who have exceptionally high weaning weights (WW), then your animal will get a low percentile for WW. If an animal is not related to the animals whose DNA was analyzed to develop these scores, then you will probably receive all high numbers, because they are less likely to share the same markers. This might make you think the animal is poor in that area when in fact he is quite good. As an example, It is possible to have an animal that weans exceptionally heavy calves but does not share the markers identified in the training population. As data is collected from their actual descendants, that data will be used to calculate EPD's and it becomes more important than the DNA analysis. The actual data collected can eventually be used by Zoetis or other labs to make adjustments to their DNA predictions. They will use the markers identified in this different pedigree to increase the accuracy of their genetic profile. This can mean that the numbers in the profile you have today will change over time.
